= Hello! =

Shoes is a tiny graphics toolkit. It's simple and straightforward. Shoes was
born to be easy!  Really, it was made for absolute beginners. There's really
nothing to it. Green Shoes is one of colorful Shoes. It is written in pure Ruby 
with Ruby/GTK2.

You see, the trivial Shoes program can be just one line:

{{{
 #!ruby
 Shoes.app{button("Click me!"){alert("Good job.")}}
}}}

Shoes programs are written in a language called Ruby.  When Shoes is handed
this simple line of Ruby code, a window appears with a button inside reading
"Click me!"  When the button is clicked, a message pops up.

On Windows 7, here's how this might look: !{margin_left: 100}man-shot1.png!

While lots of Shoes apps are graphical games and art programs, you can also
layout text and edit controls easily. !{margin_left: 80}shoes-manual-apps.png!

And, ideally, Shoes programs will run on any of the major platforms out there.
Microsoft Windows, Apple's Mac OS X, Linux and many others.

^So, welcome to Green Shoes' built-in manual. This manual is a Green Shoes program itself!^

== Introducing Green Shoes ==

How does Green Shoes look on OS X and Linux? Does it really look okay? Is it all
ugly and awkward? People must immediately convulse! It must be so watered down
trying to do everything.

Well, before getting into the stuff about installing and running Green Shoes, time to
just check out some screenshots, to give you an idea of what you can do.

==== Mac OS X ====

Green Shoes is confirmed on Apple Mac OSX10.5 PPC via X11. 
!{margin_left: 100}../snapshots/sample3-osx.png!

This is the `sample3.rb` on Mac OS X.  

All circles are drawn randomly. You can draw and animate shapes in Green Shoes.

==== Windows ====

Green Shoes is confirmed to run on '''Microsoft Windows XP''' and '''Windows 7'''.
!{margin_left: 0}../snapshots/sample33.png!

Above is pictured the `sample33.rb` running on Windows 7.  Green Shoes 
has three extended libraries for chipmunk physics, bloopsaphone and 3D texture 
mapping. First two are binary libraries, so far work on Windows only.

==== Linux ====

Here's a screenshot of the `sample44.rb` running on '''Ubuntu
on VirtualBox for Windows'''. !{margin_left: 130}../snapshots/sample44-linux.png!

This example is also draws ovals and lines to build the clock, which is animated to
show or hide itself several times each second.

Notice the text on the top of the app, showing the current time. Green Shoes has the
skills to layout words using any color, bold, italics, underlines, and supports
loading fonts.

== Installing Green Shoes ==

Okay, on to installing Green Shoes. I'm sure you're wondering: do I need to install
Ruby? Do I need to unzip anything? What commands do I need to type?

Yeah. You need to install Ruby and Gems. But, no need to worry about it.
We'll talk through all the steps.

==== Step 1: Installing Green Shoes ====

At first, install Ruby. On '''Windows''', 
visit the site of [[http://rubyinstaller.org/ RubyInstaller for Windows]] to 
download the latest '''RubyInstaller 1.9.2'''.

Then just do the following one line.

 * gem install green_shoes

That's all. Too easy?

'''Note:''' green_shoes gem is on [[http://rubygems.org/gems/green_shoes RubyGems.org]].
If you get some errors of rdoc, try to add `--no-ri --no-rdoc` option.

==== Step 2: Start a New Text File ====

Shoes programs are just plain text files ending with a '''.rb''' extension.

Here are a few ways to create a blank text file:

 * On '''Mac OS X''', visit your '''Applications''' folder and double-click on the '''TextEdit''' app.  A blank editor window should come up.  Now, go to the '''Format''' menu and select the '''Make Plain Text''' option.  Okay, you're all set! !man-editor-osx.png!
 * On '''Windows''', go to the Start menu.  Select '''All Programs''', then '''Accessories''', then '''Notepad'''. !man-editor-notepad.png!
 * On '''Linux''', most distros come with '''gedit'''.  You might try running that.  Or, if your distro is KDE-based, run '''kate'''.

Now, in your blank window, type in the following:

{{{
 require 'green_shoes'
 Shoes.app do
   para "Welcome to Shoes"
 end
}}}

Save to your desktop as `welcome.rb`.

==== Step 3: Run It! Go Shoes! ====

To run your program, just open console window and run the following.

 * ruby welcome.rb !man-editor-osx.png!

So, not much of a program yet.  But it's something!  You've got the knack of it, at least!

==== What Can You Make With Shoes? ====

Well, you can make windowing applications. But Shoes is inspired by the web, so
applications tend to use images and text layout rather than a lot of widgets.
For example, Shoes doesn't come with tabbed controls or toolbars. Shoes is a
''tiny'' toolkit, remember?

Still, Shoes does have a few widgets like buttons and edit boxes. And many
missing elements (like tabbed controls or toolbars) can be simulated with
images.

Shoes is written in part thanks to a very good art engine called Cairo, which
is used for drawing with shapes and colors. Also thanks to an awesome text 
lay out engine called Pango. In this way, Shoes is inspired by
NodeBox and Processing, two very good languages for drawing animated graphics.

== The Rules of Green Shoes ==

Time to stop guessing how Green Shoes works.  Some of the tricky things will come
back to haunt you.  I've boiled down the central rules to Green Shoes.  These are the
things you MUST know to really make it all work.

These are general rules found throughout Green Shoes.  While Green Shoes has an overall
philosophy of simplicity and clarity, there are a few points that need to be
studied and remembered.

==== Shoes Tricky Blocks ====

Okay, this is absolutely crucial.  Green Shoes does a trick with blocks.  This trick
makes everything easier to read.  But it also can make blocks harder to use
once you're in deep.

'''Let's take a normal Ruby block:'''

{{{
 Shoes.app do
   ary = ['potion', 'swords', 'shields']
   ary.each do |item|
     puts item
   end
 end
}}}

In Green Shoes, these sorts of blocks work the same.  This block above loops through
the array and stores each object in the `item` variable.  The `item` variable
disappears (goes out of scope) when the block ends.

One other thing to keep in mind is that `self` stays the same inside normal
Ruby blocks.  Whatever `self` was before the call to `each`, it is the same
inside the `each` block.

'''Both of these things are also true for most Green Shoes blocks.'''

{{{
 Shoes.app do
   stack do
     para "First"
     para "Second"
     para "Third"
   end
 end
}}}

Here we have two blocks.  The first block is sent to `Shoes.app`.  This `app`
block changes `self`.

The other block is the `stack` block.  That block does NOT change self.

'''For what reason does the `app` block change self?'''  Let's start by
spelling out that last example completely.

{{{
 Shoes.app do
   self.stack do
     self.para "First"
     self.para "Second"
     self.para "Third"
   end
 end
}}}

All of the `self`s in the above example are the App object.  Green Shoes uses Ruby's
`instance_eval` to change self inside the `app` block.  So the method calls to
`stack` and `para` get sent to the app.

'''This also is why you can use instance variables throughout a Shoes app:'''

{{{
 Shoes.app do
   @s = stack do
     @p1 = para "First"
     @p2 = para "Second"
     @p3 = para "Third"
   end
 end
}}}

These instance variables will all end up inside the App object.

'''Whenever you create a new Shoes.app window, `self` is also changed.'''

{{{
 Shoes.app title: "MAIN" do
   para self
   button "Spawn" do
     Shoes.app title: "CHILD" do
       para self
     end
   end
 end
}}}

''Note: para method displays self with [ and ] in Green Shoes.''

==== Block Redirection ====

The `stack` block is a different story, though.  It doesn't change `self` and
it's basically a regular block.

'''But there's a trick:''' when you attach a `stack` and give it a block, the
App object places that stack in its memory.  The stack gets popped off when the
block ends.  So all drawing inside the block gets '''redirected''' from the
App's top slot to the new stack.

So those three `para`s will get drawn on the `stack`, even though they actually
get sent to the App object first.

{{{
 Shoes.app do
   stack do
     para "First"
     para "Second"
     para "Third"
   end
 end
}}}

A bit tricky, you see?  This can bite you even if you know about it.

One way it'll get you is if you try to edit a stack somewhere else in your
program, outside the `app` block.

Like let's say you pass around a stack object.  And you have a class that edits
that object.

{{{
 class Messenger
   def initialize slot
     @slot = slot
   end
   def add msg
     para msg rescue puts $!
   end
 end
 
 Shoes.app do
   slot = stack
   m = Messenger.new slot
   m.add 'hello'
 end
}}}

So, let's assume you pass the stack object into your Messenger class when the
app starts.  And, later, when a message comes in, the `add` method gets used to
append a paragraph to that stack.  Should work, right?

Nope, it won't work.  The `para` method won't be found.  The App object isn't
around any more.  And it's the one with the `para` method.

Fortunately, each Shoes object has an `app` method that will let you reopen the
App object so you can do some further editing.

{{{
 class Messenger
   def initialize slot
     @slot = slot
   end
   def add msg
     @slot.app do
       para msg rescue puts $!
     end
   end
 end
 
 Shoes.app do
   slot = stack
   m = Messenger.new slot
   m.add 'hello'
 end
}}}

As you can imagine, the `app` object changes `self` to the App object.

So the rules here are:

1. '''Methods named "app" or which create new windows alter `self` to the App
object.'''[[BR]](This is true for both Shoes.app and Slot.app, as well as
[[Element.window]] and [[Element.dialog]].)[[BR]]
2. '''Blocks attached to stacks, flows or any manipulation method (such as
append) do not change self. Instead, they pop the slot on to the app's editing
stack.'''

==== Careful With Fixed Heights ====

Fixed widths on slots are great so you can split the window into columns.

{{{
 Shoes.app do
   flow do
     stack :width => 200 do
       background lavender
       caption "Column one"
       para "is 200 pixels wide"
     end
     stack :width => -200 do
       background bisque
       caption "Column two"
       para "is 100% minus 200 pixels wide"
     end
   end
 end
}}}

Fixed heights on slots should be less common.  Usually you want your text and
images to just flow down the window as far as they can.  Height usually happens
naturally.

The important thing here is that fixed heights actually force slots to behave
differently.  To be sure that the end of the slot is chopped off perfectly, the
slot becomes a '''nested window'''.  A new layer is created by the operating
system to keep the slot in a fixed square.

On difference between normal slots and nested window slots is that the latter
can have scrollbars.

{{{
 Shoes.app do
   stack width: 200, height: 200, scroll: true do
     background "#DFA"
     100.times do |i|
       para "Paragraph No. #{i}"
     end
   end
 end
}}}

These nested windows require more memory.  They tax the application a bit more.
So if you're experiencing some slowness with hundreds of fixed-height slots,
try a different approach.

'''Note''': Fixed height magic (the slot becomes a nested window) is not implemented 
in Green Shoes so far. Scrollbar will appear automatically but at main window only.

{{{
 Shoes.app do
   stack :width => 200 do
     background "#DFA"
     100.times do |i|
       para "Paragraph No. #{i}"
     end
   end
 end
}}}

==== Image and Shape Blocks ====

Most beginners start littering the window with shapes.  It's just easier to
throw all your rectangles and ovals in a slot.

'''However, bear in mind that Shoes will create objects for all those
shapes!'''

{{{
 Shoes.app do
   fill black.push(0.1)
   100.times do |i|
     oval i, i, i * 2 if i > 0
   end
 end
}}}

In this example, one-hundred Oval objects are created.  This isn't too bad.
But things would be slimmer if we made these into a single shape.

{{{
 # Not yet available
 Shoes.app do
   fill black(0.1)
   shape do
     100.times do |i|
       oval i, i, i * 2 if i > 0
     end
   end
 end
}}}

Oh, wait.  The ovals aren't filled in this time!  That's because the ovals have
been combined into a single huge shape.  And Shoes isn't sure where to fill in
this case.

So you usually only want to combine into a single shape when you're dealing
strictly with outlines.

Another option is to combine all those ovals into a single image.

{{{
 # Not yet available
 Shoes.app do
   fill black(0.1)
   image 300, 300 do
     100.times do |i|
       oval i, i, i * 2
     end
   end
 end
}}}

There we go!  The ovals are all combined into a single 300 x 300 pixel image.
In this case, storing that image in memory might be much bigger than having
one-hundred ovals around.  But when you're dealing with thousands of shapes,
the image block can be cheaper.

The point is: it's easy to group shapes together into image or shape blocks, so
give it a try if you're looking to gain some speed.  Shape blocks particularly
will save you some memory and speed.

'''NOTE''': Green Shoes doesn't support this magic (grouping shapes together 
into image or shape blocks) so far.

==== UTF-8 Everywhere ====

Ruby itself isn't Unicode aware.  And UTF-8 is a type of Unicode.  (See
[[http://en.wikipedia.org/wiki/UTF-8 Wikipedia]] for a full explanation of
UTF-8.)

However, UTF-8 is common on the web.  And lots of different platforms support
it.  So to cut down on the amount of conversion that Green Shoes has to do, 
Green Shoes expects all strings to be in UTF-8 format.

This is great because you can show a myriad of languages (Russian, Japanese,
Spanish, English) using UTF-8 in Green Shoes.  Just be sure that your text editor
uses UTF-8!

To illustrate:

{{{
 Shoes.app do
   stack :margin => 10 do
     @edit = edit_box do
       @para.text = @edit.text
     end
     @para = para ""
   end
 end
}}}

This app will copy anything you paste into the edit box and display it in a
Green Shoes paragraph.  You can try copying some foreign text (such as 
Greek or Japanese) into this box to see how it displays.

This is a good test because it proves that the edit box gives back UTF-8
characters.  And the paragraph can be set to any UTF-8 characters.

'''Important note:''' if some UTF-8 characters don't display for you, you will
need to change the paragraph's font.  This is especially common on OS X.

So, a good Japanese font on OS X is '''AppleGothic''' and on Windows is '''MS
UI Gothic'''.

{{{
 Shoes.app do
   para "てすと (te-su-to)",
    font: case RUBY_PLATFORM
    when /mingw/; "MS UI Gothic"
    when /darwin/; "AppleGothic, Arial"
    else "Arial"
    end
 end
}}}

Again, anything which takes a string in Green Shoes will need a UTF-8 string.
Edit boxes, edit lines, list boxes, window titles and text blocks all take UTF-8.
If you give a string with bad characters in it, an error will show up in the
console.

==== The Main App and Its Requires ====

'''NOTE:''' This rule is for Raisins. Policeman and Green Shoes use TOPLEVEL_BINDING. 
So, you can get `main`, Ruby top-level object, with the first snippet. Although you
need to use `Shoes::Para` instead of `Para` outside `Shoes.app` block.

Each Shoes app is given a little room where it can create itself.  You can
create classes and set variables and they won't be seen by other Shoes
programs.  Each program runs inside its own anonymous class.

{{{
 main = self
 Shoes.app do
   para main.to_s
 end
}}}

This anonymous class is called `(shoes)` and it's just an empty, unnamed class.
The `Shoes` module is mixed into this class (using `include Shoes`) so that you
can use either `Para` or `Shoes::Para` when referring to the paragraph class.

The advantages of this approach are:

 * Shoes apps cannot share local variables.
 * Classes created in the main app code are temporary.
 * The Shoes module can be mixed in to the anonymous class, but not the top-level environment of Ruby itself.
 * Garbage collection can clean up apps entirely once they complete.

The second part is especially important to remember.

{{{
 class Storage; end
 
 Shoes.app do
   para Storage.new
 end
}}}

The `Storage` class will disappear once the app completes.  Other apps aren't
able to use the Storage class.  And it can't be gotten to from files that are
loaded using `require`.

When you `require` code, though, that code will stick around.  It will be kept
in the Ruby top-level environment.

So, the rule is: '''keep your temporary classes in the code with the app and
keep your permanent classes in requires.'''

= Shoes =

Green Shoes is all about drawing windows and the stuff inside those windows.  Let's
focus on the window itself, for now.  The other sections [[Slots]] and
[[Elements]] cover everything that goes inside the window.

For here on, the manual reads more like a dictionary. Each page is mostly a
list of methods you can use for each topic covered. The idea is to be very
thorough and clear about everything.

So, if you've hit this far in the manual and you're still hazy about getting
started, you should probably either go back to the [[Hello! beginning]] of the
manual. Or you could try [[https://cloud.github.com/downloads/shoes/shoes/nks.pdf Nobody Knows
Shoes]], the beginner's leaflet PDF.

==== Finding Your Way ====

This section covers:

 * [[Built-in Built-in methods]] - general methods available anywhere in a Green Shoes program.
 * [[App The App window]] - methods found attached to every main Green Shoes window.
 * [[Styles The Styles Master List]] - a complete list of every style in Green Shoes.
 * [[Classes The Classes list]] - a chart showing what Green Shoes classes subclass what.
 * [[Colors The Colors list]] - a chart of all built-in colors and the [[Built-in.rgb]] numbers for each.

If you find yourself paging around a lot and not finding something, give the
[[Search]] page a try. It's the quickest way to get around.

'''Note:''' Green Shoes doesn't support Search page so far.

After this general reference, there are two other more specific sections:

 * [[Slots]] - covering [[Element.stack]] and [[Element.flow]], the two types of slots.
 * [[Elements]] - documentation for all the buttons, shapes, images, and so on.

Two really important pages in there are the [[Element Element Creation]] page
(which lists all the elements you can add) and the [[Common Common Methods]]
page (which lists methods you'll find on any slot or element.)

== Built-in Methods ==

These methods can be used anywhere throughout Green Shoes programs.

All of these commands are unusual because you don't attach them with a dot.
'''Every other method in this manual must be attached to an object with a dot.'''
But these are built-in methods (also called: Kernel methods.) Which means no dot!

A common one is `alert`:

{{{
  alert "No dots in sight"
}}}

Compare that to the method `reverse`, which isn't a Kernel method and is only
available for Arrays and Strings:

{{{
 #!ruby
 Shoes.app do
   para "Plaster of Paris".reverse
   #=> "siraP fo retsalP"
   para [:dogs, :cows, :snakes].reverse
   #=> [:snakes, :cows, :dogs]
 end
}}}

Most Green Shoes methods for drawing and making buttons and so on are attached to
slots.  See the section on [[Slots]] for more.

==== Built-in Constants ====

Green Shoes also has a handful of built-in constants which may prove useful if you
are trying to sniff out what release of Green Shoes is running.

'''DIR''' is a full path of `green_shoes/lib`. 

'''COLORS''' is a complete list of colors available to the app. 

'''FONTS''' is a complete list of fonts available to the app. 

'''VERSION''' is a Green Shoes version. 

{{{
 Shoes.app do
   para VERSION
   para fg(DIR, red)
   image File.join(DIR, '../static/gshoes-icon.png')
   para fg(FONTS.join(', '), green)
   para COLORS.map{|k, v| [k, v]}
 end
}}}

=== alert(message: a string) » nil ===

Pops up a window containing a short message.

{{{
 #!ruby
 alert "I'm afraid I must interject!"
}}}

Please use alerts sparingly, as they are incredibly annoying!  If you are using
alerts to show messages to help you debug your program, try checking out the
standard Ruby method `puts` or `p` methods.

=== ask(message: a string) » a string ===

Pops up a window and asks a question. For example, you may want to ask someone
their name.

{{{
 #!ruby
 if name = ask("Please, enter your name:")
   Shoes.app{para "Welcome, #{name}!"}
 end
}}}

When the above script is run, the person at the computer will see a window with
a blank box for entering their name. The name will then be saved in the `name`
variable.

=== ask_color(title: a string) » Shoes::Color ===

Pops up a color picker window. The program will wait for a color to be picked,
then gives you back a Color object. See the `Color` help for some ways you can
use this color.

{{{
 #!ruby
 backcolor = ask_color "Pick a background"
 Shoes.app do
   background backcolor
 end
}}}

=== ask_open_file() » a string ===

Pops up an "Open file..." window. It's the standard window which shows all of
your folders and lets you select a file to open. Hands you back the name of the
file.

{{{
 #!ruby
 filename = ask_open_file
 Shoes.app do
   para File.read(filename)
 end
}}}

=== ask_save_file() » a string ===

Pops up a "Save file..." window, similiar to `ask_open_file`, described
previously.

{{{
 #!ruby
 save_as = ask_save_file
 Shoes.app do
   para save_as
 end
}}}

=== ask_open_folder() » a string ===

Pops up an "Open folder..." window. It's the standard window which shows all of
your folders and lets you select a folder to open. Hands you back the name of
the folder.

{{{
 #!ruby
 folder = ask_open_folder
 Shoes.app do
   para Dir.entries(folder)
 end
}}}

=== ask_save_folder() » a string ===

Pops up a "Save folder..." window, similiar to `ask_open_folder`, described
previously. 

{{{
 #!ruby
 save_to = ask_save_folder
 Shoes.app do
   para save_to
 end
}}}


=== confirm(question: a string) » true or false ===

Pops up a yes-or-no question. If the person at the computer, clicks '''yes''',
you'll get back a `true`. If not, you'll get back `false`.

{{{
 #!ruby
 if confirm("Draw a circle?")
  Shoes.app{ oval top: 0, left: 0, radius: 50 }
 end
}}}

=== exit() ===

Stops your program. Call this anytime you want to suddenly call it quits.

'''PLEASE NOTE:''' If you need to use Ruby's own `exit` method (like in a
forked Ruby process,) call `Kernel.exit`.

=== font(message: a string) » an array of font family names ===

Loads a TrueType (or other type of font) from a file.  While TrueType is
supported by all platforms, your platform may support other types of fonts.
Shoes uses each operating system's built-in font system to make this work.

'''Note:''' Green Shoes doesn't support font method so far.

Here's a rough idea of what fonts work on which platforms:

 * Bitmap fonts (.bdf, .pcf, .snf) - Linux
 * Font resource (.fon) - Windows
 * Windows bitmap font file (.fnt) - Linux, Windows
 * PostScript OpenType font (.otf) - Mac OS X, Linux, Windows
 * Type1 multiple master (.mmm) - Windows
 * Type1 font bits (.pfb) - Linux, Windows
 * Type1 font metrics (.pfm) - Linux, Windows
 * TrueType font (.ttf) - Mac OS X, Linux, Windows
 * TrueType collection (.ttc) - Mac OS X, Linux, Windows

If the font is properly loaded, you'll get back an array of font names found in
the file.  Otherwise, `nil` is returned if no fonts were found in the file.

Also of interest: the `Shoes::FONTS` constant is a complete list of fonts
available to you on this platform.  You can check for a certain font by using
`include?`.

{{{
  if Shoes::FONTS.include? "Coolvetica"
    alert "Coolvetica is available on this system."
  else
    alert "You do not have the Coolvetica font."
  end
}}}

If you have trouble with fonts showing up, make sure your app loads the font
before it is used.  Especially on OS X, if fonts are used before they are
loaded, the font cache will tend to ignore loaded fonts.

=== gradient(color1, color2) » a range of RGB array ===

Builds a linear gradient from two colors. For each color, you may pass in 
a color/rgb method or a string describing the color. The `gradient(green, red)` is 
the same as `green..red` for example. Also possible to use different kind of args 
like this: `gradient(green, '#FA3')`

{{{
 Shoes.app do
   oval 100, 100, 100,
     fill: gradient(green, '#FA3'), angle: 45
 end
}}}

=== gray(the numbers: darkness, alpha) » a RGB array ===

Create a grayscale color from a level of darkness and, optionally, an alpha
level.

{{{
 Shoes.app do
  nostroke
  11.times do |i|
    y = x = 50 + 10 * i
    r = 200 - 10 * i
    oval x, y, r, fill: gray(1-i*0.1)
  end
 end
}}}

=== rgb(red, green, blue, alpha) » an array of decimal numbers ===

Create a color from red, green and blue components.  An alpha level (indicating
transparency) can also be added, optionally.

When passing in a whole number, use values from 0 to 255.

{{{
 Shoes.app do
   blueviolet = rgb(138, 43, 226, 0.5)
   darkgreen = rgb(0, 100, 0, 0.5)
   oval 100, 100, 100,
     fill: [blueviolet, darkgreen].sample(1)
 end
}}}

Or, use a decimal number from 0.0 to 1.0.

{{{
 Shoes.app do
   blueviolet = rgb(0.54, 0.17, 0.89)
   darkgreen = rgb(0, 0.4, 0)
   oval 100, 100, 100,
     fill: [blueviolet, darkgreen].sample(1)
 end
}}}

== The App Object ==

An App is a single window running code at a URL. When you switch URLs, a new
App object is created and filled up with stacks, flows and other Green Shoes
elements.

The App is the window itself. Which may be closed or cleared and filled with
new elements. !{:margin_left => 100}../snapshots/sample46.png!

The App itself, in slot/box terminology, is a flow.  See the ''Slots'' section
for more, but this just means that any elements placed directly at the
top-level will flow.

=== Shoes.app(styles) { ... } » Shoes::App ===

Starts up a Green Shoes app window.  This is the starting place for making a Green 
Shoes program.  Inside the block, you fill the window with various Green Shoes 
elements (buttons, artwork, etc.) and, outside the block, you use the `styles` to
describe how big the window is.  Perhaps also the name of the app.

{{{
 #!ruby
 Shoes.app title: "White Circle",
   width: 200, height: 200 do
   background black
   fill white
   oval top: 20, left: 20, radius: 160
 end
}}}

In the case above, a small window is built.  200 pixels by 200 pixels.
And, inside the window, two elements: a black background and a
white circle.

Once an app is created, it is added to the [[App.Shoes.APPS]] list.  If you
want an app to spawn more windows, see the [[Element.window]] method and the
[[Element.dialog]] method.

=== Shoes.APPS() » An array of Shoes::App objects ===

Builds a complete list of all the Green Shoes apps that are open right now.  Once an
app is closed, it is removed from the list.  Yes, you can run many apps at once
in Green Shoes.  It's completely encouraged.

{{{
 Shoes.app do
   button('Open a new app'){Shoes.app{}}
   button('Print Shoes.APPS'){p Shoes.APPS}
 end
}}}

=== clipboard() » a string ===

Returns a string containing all of the text that's on the system clipboard.
This is the global clipboard that every program on the computer cuts and pastes
into.

=== clipboard = a string ===

Stores `a string` of text in the system clipboard.

=== close() ===

Closes the app window.  If multiple windows are open and you want to close the
entire application, use the built-in method `exit`.

{{{
 Shoes.app do
  para 'hello'
  button 'spawn' do
   Shoes.app do
    para 'hello'
    button('close: close this window only'){close}
    button('exit: quit Green Shoes'){exit}
   end
  end
  button('close: close this window only'){close}
  button('exit: quit Green Shoes'){exit}
 end
}}}

=== download(url: a string, styles) ===

Starts a download thread (much like XMLHttpRequest, if you're familiar with
JavaScript.)  This method returns immediately and runs the download in the
background.  Each download thread also fires `start`, `progress` and `finish`
events.  You can send the download to a file or just get back a string (in the
`finish` event.)

If you attach a block to a download, it'll get called as the `finish` event.

{{{
 Shoes.app do
   stack do
     title "Searching Google", size: 16
     @status = para "One moment..."
 
     download "http://is.gd/bXTVY7" do |goog|
       @status.text = "Headers: #{goog.meta}"
     end
   end
 end
}}}

This example is truly the simplest form of `download`:
pulling some web data down into memory and handling it once it's done.

Another simple use of `download` is to save some web data to a file, using the
`:save` style.

{{{
 Shoes.app do
   stack do
     title "Downloading Google image", size: 16
     @status = para "One moment..."
 
     download "http://is.gd/GVAGF7",
       :save => "nasa50th.gif" do
	@status.text = "Okay, is downloaded."
	image "nasa50th.gif", top: 100
     end
   end
 end
}}}

If you need to send certain headers or actions to the web server, you can use
the `:method`, `:headers` and `:body` styles to customize the HTTP request.
(And, if you need to go beyond these, you can always break out Ruby's OpenURI
class.)

{{{
 #!ruby
 # Not yet available
 Shoes.app do
   stack do
     title "GET Google", size: 16
     @status = para "One moment..."
 
     download "http://is.gd/bXTVY7", 
         :method => "GET" do |dump|
       @status.text = dump.response.body
     end
   end
 end
}}}

As you can see from the above example, Shoes makes use of the "GET" method to
query google's search engine.

'''Note:''' Green Shoes doesn't support the `:method`, `:headers` and `:body` styles.

{{{
 include Hpricot
 Shoes.app do
   status = para "One moment..."
   download 'http://is.gd/BatiRt' do |dl|
     samples = []
     Hpricot(dl).inner_text.each_line do |line|
       samples.push($1) if line =~ /(sample.*\.rb)/
     end
     status.text = samples.join(', ')
     flush
   end
 end
}}}

As you can see from the above example, Green Shoes includes the Hpricot
library for parsing HTML.

'''Note''': Windows platform only so far.

=== location() » a string ===

Gets a string containing the URL of the current app.

'''Note:''' Green Shoes doesn't support location method so far.

=== mouse() » an array of numbers: button, left, top ===

Identifies the mouse cursor's location, along with which button is being
pressed.

{{{
 #!ruby
 Shoes.app do
   @p = para
   animate do
     button, left, top = self.mouse
     @p.replace "mouse: #{button}, #{left}, #{top}"
   end
 end
}}}

=== owner() » Shoes::App ===

Gets the app which launched this app.  In most cases, this will be `nil`.  But
if this app was launched using the [[Element.window]] method, the owner will be
the app which called `window`.

'''Note:''' Green Shoes doesn't support owner method so far.

=== started?() » true or false ===

Has the window been fully constructed and displayed?  This is useful for
threaded code which may try to use the window before it is completely built.
(Also see the `start` event which fires once the window is open.)

'''Note:''' Green Shoes doesn't support started? method so far.

=== visit(url: a string) ===

Changes the location, in order to view a different Shoes URL.

Absolute URLs (such as http://google.com) are okay, but Green Shoes will be expecting
a Green Shoes application to be at that address.  (So, google.com won't work, as it's
an HTML app.)

== The Styles Master List ==

You want to mess with the look of things?  Well, throughout Green Shoes, styles are
used to change the way elements appear.  In some cases, you can even style an
entire class of elements.  (Like giving all links without an underline.)

Styles are easy to spot.  They usually show up when the element is created.

{{{
 Shoes.app title: "A Styling Sample" do
   para 'Green Shoes', align: 'center', size: 50
 end
}}}

Here we've got a `:title` style on the app.  And on the paragraph inside the
app, a center `:align` style and 50 font `:size` style.

The style hash can also be changed by using the [[Common.style]] method,
available on every element and slot.

'''Note:''' Green Shoes can change style hash on Shape element only so far.

{{{
 Shoes.app title: "A Styling Sample" do
   choose = 
     lambda{[red, blue, green, yellow].sample}
   s = star 100, 50, 30, 200, 180, strokewidth: 5
   button 'change colors' do
     s.style stroke: choose.call, fill: choose.call
   end
 end
}}}

Most styles can also be set by calling them as methods.  (I'd use the manual
search to find the method.)

'''Note:''' Green Shoes doesn't support them as methods.

{{{
 # Not yet available
 Shoes.app title: "A Styling Sample" do
   choose = 
     lambda{[red, blue, green, yellow].sample}
   s = star 100, 50, 30, 200, 180, strokewidth: 5
   button 'change colors' do
     s.stroke = choose.call; s.fill = choose.call
   end
 end
}}}

Rather than making you plow through the whole manual to figure out what styles
go where, this helpful page speeds through every style in Green Shoes and suggests
where that style is used.

=== :align » a string ===

For: ''banner, caption, inscription, para, subtitle, tagline, title''

The alignment of the text. It is either:

 * "left" - Align the text to the left.
 * "center" - Align the text in the center.
 * "right" - Align the text to the right.

=== :angle » a number ===

For: ''background, border, line, oval, rect, shape, star''.

The angle at which to apply a gradient.  Normally, gradient colors range from
top to bottom.  If the `:angle` is set to 90, the gradient will rotate 90
degrees counter-clockwise and the gradient will go from left to right.

=== :attach » a slot or element ===

For: ''flow, stack''.

Pins a slot relative to another slot or element.  Also, one may write `:attach
=> Window` to position the slot at the window's top, left corner.  Taking this
a bit further, the style `:top => 10, :left => 10, :attach => Window` would
place the slot at (10, 10) in the window's coordinates.

If a slot is attached to an element that moves, the slot will move with it.  If
the attachment is reset to `nil`, the slot will flow in with the other objects
that surround, as normal.

'''Note:''' Green Shoes doesn't support `:attach` style.

=== :autoplay » true or false ===

For: ''video''.

Should this video begin playing after it appears?  If set to `true`, the video
will start without asking the user.

'''Note:''' Green Shoes doesn't support ''video''.

=== :bottom » a number ===

For: ''all slots and elements''.

Sets the pixel coordinate of an element's lower edge.  The edge is placed
relative to its container's lower edge.  So, `:bottom => 0` will align the
element so that its bottom edge and the bottom edge of its slot touch.

'''Note:''' Green Shoes doesn't support `:bottom` style.

=== :cap » :curve or :rect or :project ===

For: ''arc, arrow, border, flow, image, mask, rect, star, shape, stack''.

Sets the shape of the line endpoint, whether curved or square.  See the
[[Art.cap]] method for more explanation.

'''Note:''' Green Shoes doesn't support `:cap` style.

=== :center » true or false ===

For: ''arc, image, oval, rect, shape''.

Indicates whether the `:top` and `:left` coordinates refer to the center of the
shape or not.  If set to `true`, this is similar to setting the
[[Art.transform]] method to `:center`.

'''Note:''' Green Shoes doesn't support `:center` style.

=== :change » a proc ===

For: ''edit_box, edit_line, list_box''.

The `change` event handler is stored in this style.  See the [[EditBox.change]]
method for the edit_box, as an example.

'''Note:''' Green Shoes doesn't support `:change` style.

=== :checked » true or false ===

For: ''check, radio''.

Is this checkbox or radio button checked?  If set to `true`, the box is
checked.  Also see the [[Check.checked=]] method.

=== :choose » a string ===

For: ''list_box''.

Sets the currently chosen item in the list.  More information at
[[ListBox.choose]].

=== :click » a proc ===

For: ''arc, arrow, banner, button, caption, check, flow, image, inscription,
line, link, mask, oval, para, radio, rect, shape, stack, star, subtitle,
tagline, title''.

The `click` event handler is stored in this style.  See the [[Events.click]]
method for a description.

'''Note:''' Green Shoes doesn't support `:click` style.

=== :curve » a number ===

For: ''background, border, rect''.

The radius of curved corners on each of these rectangular elements.  As an
example, if this is set to 6, the corners of the rectangle are given a curve
with a 6-pixel radius.

=== :displace_left » a number ===

For: ''all slots and elements''.

Moves a shape, text block or any other kind of object to the left or right.  A
positive number displaces to the right by the given number of pixels; a
negative number displaces to the left.  Displacing an object doesn't effect the
actual layout of the page.  Before using this style, be sure to read the
[[Position.displace]] docs, since its behavior can be a bit surprising.

'''Note:''' Green Shoes doesn't support `:displace_left` style.

=== :displace_top » a number ===

For: ''all slots and elements''.

Moves a shape, text block or any other kind of object up or down.  A positive
number moves the object down by this number of pixels; a negative number moves
it up.  Displacing doesn't effect the actual layout of the page or the object's
true coordinates.  Read the [[Position.displace]] docs, since its behavior can
be a bit surprising.

'''Note:''' Green Shoes doesn't support `:displace_top` style.

=== :emphasis » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Styles the text with an emphasis (commonly italicized.)

This style recognizes three possible settings:

 * "normal" - the font is upright.
 * "oblique" - the font is slanted, but in a roman style.
 * "italic" - the font is slanted in an italic style. 

'''Note:''' Green Shoes doesn't support `:emphasis` style.

=== :family » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Styles the text with a given font family.  The string should contain the family
name or a comma-separated list of families.

'''Note:''' Green Shoes doesn't support `:family` style.

=== :fill » a hex code, a rgb array or a range of either ===

For: ''background, border, line, oval, rect, shape, star''.

The color of the background pen.  For shapes, this is the fill color, the paint
inside the shape.  

=== :font » a string ===

For: ''banner, caption, inscription, para, subtitle, tagline, title''.

Styles the text with a font description.  The string is pretty flexible, but
can take the form "[FAMILY-LIST] [STYLE-OPTIONS] [SIZE]", where FAMILY-LIST is
a comma separated list of families optionally terminated by a comma,
STYLE_OPTIONS is a whitespace separated list of words where each WORD describes
one of style, variant, weight, stretch, or gravity, and SIZE is a decimal
number (size in points) or optionally followed by the unit modifier "px" for
absolute size. Any one of the options may be absent. If FAMILY-LIST is absent,
then the default font family (Arial) will be used.

=== :group » a string ===

For: ''radio''.

Indicates what group a radio button belongs to.  Without this setting, radio
buttons are grouped together with other radio buttons in their immediate slot.
"Grouping" radio buttons doesn't mean they'll be grouped next to each other on
the screen.  It means that only one radio button from the group can be selected
at a time.

By giving this style a string, the radio button will be grouped with other
radio buttons that have the same group name.

'''Note:''' Green Shoes doesn't support ''radio''.

=== :height » a number ===

For: ''all slots and elements''.

Sets the pixel height of this object.  If the number is a decimal number, the
height becomes a percentage of its parent's height (with 0.0 being 0% and 1.0
being 100%.)

=== :hidden » true or false ===

For: ''all slots and elements''.

Hides or shows this object.  Any object with `hidden: true` are not
displayed on the screen.  Neither are its children.

{{{
 Shoes.app do
   slot = stack hidden: true do
     title 'hello'
     flow do
       image File.join DIR, '../samples/loogink.png'
     end
     para link('Go go!'){alert 'hi'}
   end
   timer(2){slot.show}
   timer(5){slot.hide}
 end
}}}

'''Note:''' Green Shoes supports `:hidden` style for only slots, shapes, textblocks 
and images so far.

=== :inner » a number ===

For: ''star''.

The size of the inner radius (in pixels.)  The inner radius describes the solid
circle within the star where the points begin to separate.

=== :items » an array ===

For: ''list_box''.

The list of selections in the list box.  See the [[Element.list_box]] method
for an example.

=== :justify » true or false ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''

Evenly spaces the text horizontally.

'''Note:''' Green Shoes doesn't support `:justify` style.

=== :kerning » a number ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Adds to the natural spacing between letters, in pixels.

'''Note:''' Green Shoes doesn't support `:kerning` style.

=== :leading » a number ===

For: ''banner, caption, inscription, para, subtitle, tagline, title''.

Sets the spacing between lines in a text block.  Defaults to 4 pixels.

'''Note:''' Green Shoes doesn't support `:leading` style.

=== :left » a number ===

For: ''all slots and elements''.

Sets the left coordinate of this object to a specific pixel.  Setting `left: 10` 
places the object's left edge ten pixels away from the left edge of the
slot containing it.  If this style is left unset (or set to `nil`,) the object
will flow in with the other objects surrounding it.

=== :margin » a number or an array of four numbers ===

For: ''all slots and elements''.

Margins space an element out from its surroundings.  Each element has a left,
top, right, and bottom margin.  If the `:margin` style is set to a single
number, the spacing around the element uniformly matches that number.  In other
words, if `margin: 8` is set, all the margins around the element are set to
eight pixels in length.

This style can also be given an array of four numbers in the form `[left, top,
right, bottom]`.

=== :margin_bottom » a number ===

For: ''all slots and elements''.

Sets the bottom margin of the element to a specific pixel size.

=== :margin_left » a number ===

For: ''all slots and elements''.

Sets the left margin of the element to a specific pixel size.

=== :margin_right » a number ===

For: ''all slots and elements''.

Sets the right margin of the element to a specific pixel size.

=== :margin_top » a number ===

For: ''all slots and elements''.

Sets the top margin of the element to a specific pixel size.

=== :outer » a number ===

For: ''star''.

Sets the outer radius (half of the ''total'' width) of the star, in pixels.

=== :points » a number ===

For: ''star''.

How many points does this star have?  A style of `points: 5` creates a
five-pointed star.

=== :radius » a number ===

For: ''oval''.

Sets the radius (half of the diameter or total width) for each of these
elements.  Setting this is equivalent to setting both `:width` and `:height` to
double this number.

=== :right » a number ===

For: ''all slots and elements''.

Sets the pixel coordinate of an element's right edge.  The edge is placed
relative to its container's rightmost edge.  So, `:right => 0` will align the
element so that its own right edge and the right edge of its slot touch.
Whereas `:right => 20` will position the right edge of the element off to the
left of its slot's right edge by twenty pixels.

'''Note:''' Green Shoes doesn't support `:right` style.

=== :rise » a number ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Lifts or plunges the font baseline for some text.  For example, a
[[Element.sup]] has a `:rise` of 10 pixels.  Conversely, the [[Element.sub]]
element has a `:rise` of -10 pixels.

'''Note:''' Green Shoes doesn't support `:rise` style.

=== :scroll » true or false ===

For: ''flow, stack''.

Establishes this slot as a scrolling slot.  If `:scroll => true` is set, the
slot will show a scrollbar if any of its contents go past its height.  The
scrollbar will appear and disappear as needed.  It will also appear inside the
width of the slot, meaning the slot's width will never change, regardless of
whether there is a scrollbar or not.

'''Note:''' Green Shoes doesn't support `:scroll` style.

=== :secret » true or false ===

For: ''ask, edit_line''.

Used for password fields, this setting keeps any characters typed in from
becoming visible on the screen.  Instead, a replacement character (such as an
asterisk) is show for each letter typed.

'''Note:''' Green Shoes doesn't support `:secret` style.

=== :size » a number ===

For: ''banner, caption, inscription, para, subtitle, tagline, title''.

Sets the pixel size for the font used inside this text block.

Font size may also be augmented, through use of the following strings:

 * "xx-small" - 57% of present size.
 * "x-small" - 64% of present size.
 * "small" - 83% of present size.
 * "medium" - no change in size.
 * "large" - 120% of present size.
 * "x-large" - 143% of present size.
 * "xx-large" - 173% of present size.

'''Note:''' Green Shoes doesn't support as the above string style settings.

=== :state » a string ===

For: ''button, check, edit_box, edit_line, list_box, radio''.

The `:state` style is for disabling or locking certain controls, if you don't
want them to be edited.

Here are the possible style settings:

 * nil - the control is active and editable.
 * "readonly" - the control is active but cannot be edited.
 * "disabled" - the control is not active (grayed out) and cannot be edited.

'''Note:''' Green Shoes doesn't support `:state` style.

=== :stretch » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Sets the font stretching used for a text object.

Possible settings are:

 * "condensed" - a smaller width of letters.
 * "normal" - the standard width of letters.
 * "expanded" - a larger width of letters.

'''Note:''' Green Shoes doesn't support `:stretch` style.

=== :strikecolor » a Shoes::Color ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

The color used to paint any lines stricken through this text.

'''Note:''' Green Shoes doesn't support `:strikecolor` style.

=== :strikethrough » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Is this text stricken through?  Two options here:

 * "none" - no strikethrough
 * "single" - a single-line strikethrough.

'''Note:''' Green Shoes doesn't support `:strikethrough` style.

=== :stroke » a hex code, a rgb array or a range of either ===

For: ''background, border, line, oval, rect, shape, star''.

The color of the foreground pen.  In the case of shapes, this is the color the
lines are drawn with. 

=== :strokewidth » a number ===

For: ''background, border, line, oval, rect, shape, star''.

The thickness of the stroke, in pixels, of the line defining each of these
shapes.  For example, the number two would set the strokewidth to 2 pixels.

=== :text » a string ===

For: ''edit_box, edit_line''.

Sets the message displayed on the contents of edit_box or edit_line.

=== :top » a number ===

For: ''all slots and elements''.

Sets the top coordinate for an object, relative to the top slot (window).  If an
object is set with `top: 40`, this means the object's top edge will be
placed 40 pixels beneath the top edge of the top slot (window).  If no
`:top` style is given, the object is automatically placed in the natural flow
of the slot it contains.

=== :undercolor » a Shoes::Color ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

The color used to underline text.

'''Note:''' Green Shoes doesn't support `:undercolor` style.

=== :underline » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Dictates the style of underline used in the text.

The choices for this setting are:

 * "none" - no underline at all.
 * "single" - a continuous underline.
 * "double" - two continuous parallel underlines.
 * "low" - a lower underline, beneath the font baseline.  (This is generally recommended only for single characters, particularly when showing keyboard accelerators.)
 * "error" - a wavy underline, usually found indicating a misspelling.

'''Note:''' Green Shoes doesn't support `:underline` style.

=== :variant » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Vary the font for a group of text.  Two choices:

 * "normal" - standard font.
 * "smallcaps" - font with the lower case characters replaced by smaller variants of the capital characters. 

'''Note:''' Green Shoes doesn't support `:variant` style.

=== :weight » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''.

Set the boldness of the text.  Commonly, this style is set to one of the
following strings:

 * "ultralight" - the ultralight weight (= 200)
 * "light" - the light weight (= 300)
 * "normal" - the default weight (= 400)
 * "semibold" - a weight intermediate between normal and bold (= 600)
 * "bold" - the bold weight (= 700)
 * "ultrabold" - the ultrabold weight (= 800)
 * "heavy" - the heavy weight (= 900)

However, you may also pass in the numerical weight directly.

'''Note:''' Green Shoes doesn't support `:weight` style.

=== :width » a number ===

For: ''all slots and elements''.

Sets the pixel width for the element.  If the number is a decimal, the width is
converted to a percentage (with 0.0 being 0% and 1.0 being 100%.)  A width of
100% means the object fills its parent slot.

=== :wrap » a string ===

For: ''banner, caption, code, del, em, ins, inscription, link, para, span,
strong, sub, sup, subtitle, tagline, title''

How should the text wrap when it fills its width? Possible options are:

 * "word" - Break lines at word breaks.
 * "char" - Break lines between characters, thus breaking some words.
 * "trim" - Cut the line off with an ellipsis if it goes too long.

'''Note:''' Green Shoes doesn't support `:wrap` style.

== Classes List ==

There is a complete list of all the classes introduced by Green Shoes.  

Look at [[http://rdoc.info/github/ashbb/green_shoes/master/frames/file/README.md Green Shoes RDoc]].

== Colors List ==

The following list of colors can be used throughout Green Shoes.  As background
colors or border colors.  As stroke and fill colors.  Most of these colors come
from the X11 and HTML palettes.

All of these colors can be used by name.  (So calling the `tomato` method from
inside any slot will get you a nice reddish color.)  Below each color, also
find the exact numbers which can be used with the [[Built-in.rgb]] method.

{COLORS}

= Slots =

Slots are boxes used to lay out images, text and so on. The two most common
slots are `stacks` and `flows`. Slots can also be referred to as "boxes" or
"canvases" in Green Shoes terminology.

Since the mouse wheel and PageUp and PageDown are so pervasive on every
platform, vertical scrolling has really become the only overflow that matters.
So, in Green Shoes, just as on the web, width is generally fixed. While height goes
on and on.

Now, you can also just use specific widths and heights for everything, if you
want. That'll take some math, but everything could be perfect.

Generally, I'd suggest using stacks and flows. The idea here is that you want
to fill up a certain width with things, then advance down the page, filling up
further widths. You can think of these as being analogous to HTML's "block" and
"inline" styles.

==== Stacks ====

A stack is simply a vertical stack of elements. Each element in a stack is
placed directly under the element preceding it.

A stack is also shaped like a box. So if a stack is given a width of 250, that
stack is itself an element which is 250 pixels wide.

To create a new stack, use the [[Element.stack]] method, which is available
inside any slot.  So stacks can contain other stacks and flows.

==== Flows ====

A flow will pack elements in as tightly as it can. A width will be filled, then
will wrap beneath those elements. Text elements placed next to each other will
appear as a single paragraph. Images and widgets will run together as a series.

Like the stack, a flow is a box. So stacks and flows can safely be embedded
and, without respect to their contents, are identical. They just treat their
contents differently.

Making a flow means calling the [[Element.flow]] method.  Flows may contain
other flows and stacks.

Last thing: The Green Shoes window itself is a flow.

== Art for Slots ==

Each slot is like a canvas, a blank surface which can be covered with an
assortment of colored shapes or gradients.

Many common shapes can be drawn with methods like `oval` and `rect`.  You'll
need to set up the paintbrush colors first, though.

The `stroke` command sets the line color.  And the `fill` command sets the
color used to paint inside the lines.

{{{
 #!ruby
 Shoes.app do
   stroke red
   fill blue
   oval top: 10, left: 10, radius: 100
 end
}}}

That code gives you a blue pie with a red line around it.  One-hundred pixels
wide, placed just a few pixels southeast of the window's upper left corner.

The `blue` and `red` methods above are RGB array.  See the section on
Colors for more on how to mix colors.

==== Inspiration from Processing and NodeBox ====

The artful methods generally come verbatim from NodeBox, a drawing kit for
Python.  In turn, NodeBox gets much of its ideas from Processing, a Java-like
language for graphics and animation.  I owe a great debt to the creators of
these wonderful programs!

Green Shoes does a few things differently from NodeBox and Processing.  For example,
Green Shoes has different color methods, including having its own RGB array,
though these are very similar to Processing's color methods.  And Green Shoes also
allows images and gradients to be used for drawing lines and filling in shapes.

Shoes also borrows some animation ideas from Processing and will continue to
closely consult Processing's methods as it expands.

=== arc(left, top, width, height, angle1, angle2) » Shoes::Oval ===

Draws an arc shape (a section of an oval) at coordinates (left, top).  This
method just give you a bit more control than [[oval]], by offering the
`:angle1` and `:angle2` styles.  (In fact, you can mimick the `oval` method by
setting `:angle1` to 0 and `:angle2` to `2*Math::PI`.)

{{{
 Shoes.app do
   fill yellow..green
   stroke red..blue
   strokewidth 10
   cap :curve
 
   a = animate 12 do |i|
     @e.remove if @e
     r = i * (Math::PI * 0.01)
     @e = arc 100, 50, 180, 360, 0, r
     a.stop if r >= 2*Math::PI
   end
 end
}}}

=== arrow(left, top, width) » Shoes::Shape ===

Draws an arrow at coordinates (left, top) with a pixel `width`.

{{{
 Shoes.app do
   para 'An arrow shape:', left: 20, top: 10
   arrow 30, 40, 70
 end
}}}

=== cap(:curve or :rect or :project) » self ===

Sets the line cap, which is the shape at the end of every line you draw.  If
set to `:curve`, the end is rounded.  The default is `:rect`, a line which ends
abruptly flat.  The `:project` cap is also fat, but sticks out a bit longer.

{{{
 Shoes.app do
   nofill
   strokewidth 20
   stroke green
   cap :curve
   line 100, 100, 300, 100
   line 100, 250, 300, 300
   cap :rect
   line 100, 150, 300, 150
   stroke blue
   cap :project
   line 100, 200, 300, 200
   line 200, 100, 200, 300
   strokewidth 1
   stroke red
   rect 100, 100, 200, 200
 end
}}}

=== fill(pattern) » pattern ===

Sets the fill bucket to a specific color (or pattern.)  Patterns can be colors,
gradients or images.  So, once the fill bucket is set, you can draw shapes and
they will be colored in with the pattern you've chosen.

To draw a star with an image pattern:

{{{
 #!ruby
 Shoes.app do
   fill File.join(DIR, "../static/gshoes-icon.png")
   star 200, 200, 5, 100, 50
 end
}}}

To clear the fill bucket, use `nofill`.  And to set the line color (the border
of the star,) use the `stroke` method.

=== nofill() » self ===

Blanks the fill color, so that any shapes drawn will not be filled in.
Instead, shapes will have only a lining, leaving the middle transparent.

=== nostroke() » self ===

Empties the line color.  Shapes drawn will have no outer line.  If `nofill` is
also set, shapes drawn will not be visible.

=== line(left, top, x2, y2) » Shoes::Line ===

Draws a line using the current line color (aka "stroke") starting at
coordinates (left, top) and ending at coordinates (x2, y2).

=== oval(left, top, radius) » Shoes::Oval ===

Draws a circular form at pixel coordinates (left, top) with a width and height
of `radius` pixels.  The line and fill colors are used to draw the shape.  By
default, the coordinates are for the oval's leftmost, top corner, but this can
be changed by calling the [[Art.transform]] method or by using the `:center`
style on the next method below.

{{{
 #!ruby
 Shoes.app do
   stroke blue
   strokewidth 4
   fill black
   oval 10, 10, 50
 end
}}}

To draw an oval of varied proportions, you may also use the syntax: `oval(left, top, width, height)`.

=== oval(styles) » Shoes::Oval ===

Draw circular form using a style hash.  The following styles are supported:

 * `top`: the y-coordinate for the oval pen.
 * `left`: the x-coordinate for the oval pen.
 * `radius`: the width and height of the circle.
 * `width`: a specific pixel width for the oval.
 * `height`: a specific pixel height for the oval.
 * `center`: do the coordinates specific the oval's center? (true or false)

These styles may also be altered using the `style` method on the Shape object.

'''Note:''' Green Shoes doesn't support `center` style.

=== rect(top, left, width, height) » Shoes::Rect ===

Draws a rectangle starting from coordinates (top, left) with dimensions of
width x height. 

As with all other shapes, the rectangle is drawn using the stroke and fill colors.

{{{
 #!ruby
 Shoes.app do
   stroke rgb(0.5, 0.5, 0.7)
   fill rgb(1.0, 1.0, 0.9)
   rect 10, 10, self.width - 20, self.height - 20
 end
}}}

The above sample draws a rectangle which fills the area of its parent box,
leaving a margin of 10 pixels around the edge.  Also see the `background`
method for a rectangle which defaults to filling its parent box.

=== rect(styles) » Shoes::Rect ===

Draw a rectangle using a style hash.  The following styles are supported:

 * `top`: the y-coordinate for the rectangle.
 * `left`: the x-coordinate for the rectangle.
 * `curve`: the pixel radius of the rectangle's corners.
 * `width`: a specific pixel width for the rectangle.
 * `height`: a specific pixel height for the rectangle.
 * `center`: do the coordinates specific the rectangle's center? (true or false)

These styles may also be altered using the `style` method on the Shape object.

'''Note:''' Green Shoes doesn't support `center` style.

=== rotate(degrees: a number) » self ===

Rotates the pen used for drawing by a certain number of `degrees`, so that any
shapes will be drawn at that angle.

In this example below, the rectangle drawn at (30, 30) will be rotated 45 degrees.

{{{
 #!ruby
 Shoes.app do
   fill "#333"
   rotate 45
   rect 30, 30, 40, 40
 end
}}}

=== shape(left, top) { ... } » Shoes::Shape ===

Describes an arbitrary shape to draw, beginning at coordinates (left, top) and
continued by calls to `line_to`, `move_to`, `curve_to` and `arc_to` inside the
block.  You can look at it as sketching a shape with a long line that curves
and arcs and bends.

{{{
 Shoes.app do
   fill yellow
   shape do
     move_to 50, 30
     curve_to 100, 100, 10, 20, 100, 50
     line_to 20, 100
     line_to 30, 30
   end
 end
}}}

A shape can also contain other shapes.  So, you can place an [[Art.oval]], a
[[Art.rect]], a [[Art.line]], a [[Art.star]] or an [[Art.arrow]] (and all of
the other methods in this [[Art]] section) inside a shape, but they will not be
part of the line.  They will be more like a group of shapes are all drawn as
one.

'''Note:''' The above `line_to`, `move_to` and `curve_to` are Cairo::Context methods. 
Green Shoes uses them directly inside the block. So, Green Shoes doesn't support `arc_to`.
Also Green Shoes shape can not contain other shapes.

=== star(left, top, points = 10, outer = 100.0, inner = 50.0) » Shoes::Star ===

Draws a star using the stroke and fill colors.  The star is positioned with its
center point at coordinates (left, top) with a certain number of `points`.  The
`outer` width defines the full radius of the star; the `inner` width specifies
the radius of the star's middle, where points stem from.

=== stroke(pattern) » pattern ===

Set the active line color for this slot.  The `pattern` may be a color, a
gradient or an image, all of which are categorized as "patterns."  The line
color is then used to draw the borders of any subsequent shape.

So, to draw a star with a red line around it:

{{{
 #!ruby
 Shoes.app do
   stroke red
   nofill
   star 100, 100
 end
}}}

To clear the line color, use the `nostroke` method.

=== strokewidth(a number) » self ===

Sets the line size for all drawing within this slot.  Whereas the `stroke`
method alters the line color, the `strokewidth` method alters the line size in
pixels.  Calling `strokewidth(4)` will cause lines to be drawn 4 pixels wide.

=== transform(:center or :corner) » self ===

Should transformations (such as `skew` and `rotate`) be performed around the
center of the shape?  Or the corner of the shape?  Shoes defaults to `:corner`.

'''Note:''' Green Shoes doesn't support `transform` method.

=== translate(left, top) » self ===

Moves the starting point of the drawing pen for this slot.  Normally, the pen
starts at (0, 0) in the top-left corner, so that all shapes are drawn from that
point.  With `translate`, if the starting point is moved to (10, 20) and a
shape is drawn at (50, 60), then the shape is actually drawn at (60, 80) on the
slot.

'''Note:''' Green Shoes doesn't support `translate` method.

== Element Creation ==

Green Shoes has a wide variety of elements, many cherry-picked from HTML.  This page
describes how to create these elements in a slot.  See the Elements section of
the manual for more on how to modify and use these elements after they have
been placed.

=== animate(fps) { |frame| ... } » Shoes::Anim ===

Starts an animation timer, which runs parallel to the rest of the app.  The
`fps` is a number, the frames per seconds.  This number dictates how many times
per second the attached block will be called.

The block is given a `frame` number.  Starting with zero, the `frame` number
tells the block how many frames of the animation have been shown.

{{{
 #!ruby
 Shoes.app do
   counter = para "STARTING"
   animate 24 do |frame|
     counter.replace "FRAME #{frame}"
   end
 end
}}}

The above animation is shown 24 times per second.  If no number is given, the
`fps` defaults to 10.

=== background(pattern) » Shoes::Background ===

Draws a Background element with a specific color (or pattern.)  Patterns can be
colors, gradients or images.  Colors and images will tile across the
background.  Gradients stretch to fill the background.

'''PLEASE NOTE:''' Backgrounds are actual elements, not styles.  HTML treats
backgrounds like styles.  Which means every box can only have one background.
Green Shoes layers background elements.

{{{
 #!ruby
 Shoes.app do
   background black
   background white, width: 50
 end
}}}

The above example paints two backgrounds.  First, a black background is painted
over the entire app's surface area.  Then a 50 pixel white stripe is painted
along the left side.

=== banner(text) » Shoes::Banner ===

Creates a Banner text block.  Green Shoes automatically styles this text to 48 pixels high.

=== border(text, :strokewidth => a number) » Shoes::Border ===

Draws a Border element using a specific color (or pattern.)  Patterns can be
colors, gradients or images.  Colors and images will tile across the border.
Gradients stretch to fill the border.

'''PLEASE NOTE:''' Like Backgrounds, Borders are actual elements, not styles.
HTML treats backgrounds and borders like styles.  Which means every box can
only have one borders.  Green Shoes layers border and background elements, along with
text blocks, images, and everything else.

=== button(text) { ... } » Shoes::Button ===

Adds a push button with the message `text` written across its surface.  An
optional block can be attached, which is called if the button is pressed.

=== caption(text) » Shoes::Caption ===

Creates a Caption text block.  Green Shoes styles this text to 14 pixels high.

=== check() » Shoes::Check ===

Adds a check box.

=== code(text) » String ===

Create a Code text fragment.  This text defaults to a monospaced font.

=== del(text) » String ===

Creates a Del text fragment (short for "deleted") which defaults to text with a
single strikethrough in its middle.

=== dialog(styles) { ... } » Shoes::App ===

Opens a new app window (just like the [[Element.window]] method does,) but the
window is given a dialog box look.

'''Note:''' Green Shoes doesn't support `dialog` method.

=== edit_box(text) » Shoes::EditBox ===

Adds a large, multi-line textarea to this slot.  The `text` is optional and
should be a string that will start out the box.  An optional block can be
attached here which is called any type the user changes the text in the box.

{{{
 #!ruby
 Shoes.app do
   edit_box
   edit_box text: "HORRAY EDIT ME"
   edit_box text: "small one",
     width: 100, height: 160
 end
}}}

=== edit_line(text) » Shoes::EditLine ===

Adds a single-line text box to this slot.  The `text` is optional and should be
a string that will start out the box.  An optional block can be attached here
which is called any type the user changes the text in the box.

=== em(text) » String ===

Creates an Em text fragment (short for "emphasized") which, by default, is
styled with italics.

=== every(seconds) { |count| ... } » Shoes::Anim ===

A timer similar to the `animate` method, but much slower.  This timer fires a
given number of seconds, running the block attached.  So, for example, if you
need to check a web site every five minutes, you'd call `every(300)` with a
block containing the code to actually ping the web site.

=== flow(styles) { ... } » Shoes::Flow ===

A flow is an invisible box (or "slot") in which you place Green Shoes elements.  Both
flows and stacks are explained in great detail on the main [[Slots]] page.

Flows organize elements horizontally.  Where one would use a [[Element.stack]]
to keep things stacked vertically, a flow places its contents end-to-end across
the page.  Once the end of the page is reached, the flow starts a new line of
elements.

=== image(path) » Shoes::Image ===

Creates an [[Image]] element for displaying a picture.  PNG, JPEG and GIF
formats are allowed.

The `path` can be a file path or a URL.  All images loaded are temporarily
cached in memory, but remote images are also cached locally in the user's
personal Shoes directory.  Remote images are loaded in the background; as with
browsers, the images will not appear right away, but will be shown when they
are loaded.

'''Note:''' Green Shoes doesn't support the above personal Shoes directory.

=== imagesize(path) » [width, height] ===

Quickly grab the width and height of an image.  The image won't be loaded into
the cache or displayed.

URGENT NOTE: This method cannot be used with remote images (loaded from HTTP,
rather than the hard drive.)

=== ins(text) » String ===

Creates an Ins text fragment (short for "inserted") which Green Shoes styles with a
single underline.

=== inscription(text) » Shoes::Inscription ===

Creates an Inscription text block.  Green Shoes styles this text at 10 pixels high.

=== link(text, :click => proc or string) » Shoes::Link ===

Creates a Link text block, which Green Shoes styles with a single underline and
colors with a #06E (blue) colored stroke.

The default LinkHover style is also single-underlined with a #039 (dark blue) stroke.

=== list_box(:items => [strings, ...]) » Shoes::ListBox ===

Adds a drop-down list box containing entries for everything in the `items`
array.  An optional block may be attached, which is called if anything in the
box becomes selected by the user.

{{{
 #!ruby
 Shoes.app do
  stack  margin: 10 do
   para "Pick a card:"
   list_box items: ["Jac", "Ace", "Jok"] do |item|
    @p.text = "#{item} was picked!"
   end
   @p = para
  end
 end
}}}

Call `ListBox#text` to get the selected string.  See the `ListBox` section
under `Native` controls for more help.

=== progress() » Shoes::Progress ===

Adds a progress bar.

=== para(text) » Shoes::Para ===

Create a Para text block (short for "paragraph") which Green Shoes styles at 12
pixels high.

=== radio(group name: a string or symbol) » Shoes::Radio ===

Adds a radio button.  If a `group name` is given, the radio button is
considered part of a group.  Among radio buttons in the same group, only one
may be checked.  (If no group name is given, the radio button is grouped with
any other radio buttons in the same slot.)

=== span(text) » Shoes::Span ===

Creates a Span text fragment, unstyled by default.

'''Note:''' Green Shoes doesn't support `span` method.

=== stack(styles) { ... } » Shoes::Stack ===

Creates a new stack.  A stack is a type of slot.  (See the main [[Slots]] page
for a full explanation of both stacks and flows.)

In short, stacks are an invisible box (a "slot") for placing stuff.  As you add
things to the stack, such as buttons or images, those things pile up
vertically.  Yes, they stack up!

=== strong(text) » String ===

Creates a Strong text fragment, styled in bold by default.

=== sub(text) » String ===

Creates a Sub text fragment (short for "subscript") which defaults to lowering
the text by 10 pixels and styling it in an x-small font.

=== subtitle(text) » String ===

Creates a Subtitle text block.  Green Shoes styles this text to 26 pixels high.

=== sup(text) » String ===

Creates a Sup text fragment (short for "superscript") which defaults to raising
the text by 10 pixels and styling it in an x-small font.

=== tagline(text) » Shoes::Tagline ===

Creates a Tagline text block.  Green Shoes styles this text to 18 pixels high.

=== timer(seconds) { ... } » Fixnum ===

A one-shot timer.  If you want to schedule to run some code in a few seconds
(or minutes, hours) you can attach the code as a block here.

To display an alert box five seconds from now:

{{{
 #!ruby
 Shoes.app do
   timer 5 do
     alert "Your five seconds are up."
   end
 end
}}}

=== title(text) » Shoes::Title ===

Creates a Title text block.  Green Shoes styles these elements to 34 pixels high.

=== video(path or url) » Shoes::Video ===

Embeds a movie in this slot.

'''Note:''' Green Shoes doesn't support `video` method.

=== window(styles) { ... } » Shoes::App ===

Opens a new app window.  This method is almost identical to the
[[App.Shoes.app]] method used to start an app in the first place.  The
difference is that the `window` method sets the new window's [[App.owner]]
property.  (A normal Shoes.app has its `owner` set to `nil`.)

So, the new window's `owner` will be set to the Shoes::App which launched the
window.  This way the child window can call the parent.

{{{
 #!ruby
 Shoes.app title: "The Owner" do
   button "Pop up?" do
     window do
       para "Okay, popped up from [#{owner}]."
     end
   end
 end
}}}

== Events ==

Wondering how to catch stray mouse clicks or keyboard typing?  Events are sent
to a slot whenever a mouse moves inside the slot.  Or whenever a key is
pressed.  Even when the slot is created or destroyed.  You can attach a block
to each of these events.

Mouse events include `motion`, `click`, `release`, `hover` and `leave`.  Keyboard typing
is represented by the `keypress` event.  And the `start` and `finish` events
indicate when a canvas comes into play or is discarded.

So, let's say you want to change the background of a slot whenever the mouse
floats over it.  We can use the `hover` event to change the background when the
mouse comes inside the slot.  And `leave` to change back when the mouse floats
away.

{{{
 #!ruby
 Shoes.app do
   s = stack width: 200, height: 200 do
     background red
   end
   s.hover do
     s.clear { background blue }
   end
   s.leave do
     s.clear { background red }
   end
 end
}}}

=== click { |button, left, top| ... } » self ===

The click block is called when a mouse button is clicked.  The `button` is the
number of the mouse button which has been pressed.  The `left` and `top` are
the mouse coordinates at which the click happened.

To catch the moment when the mouse is unclicked, see the [[Events.release]] event.

=== finish { |self| ... } » self ===

When a slot is removed, it's finish event occurs.  The finish block is
immediately handed `self`, the slot object which has been removed.

'''Note:''' Green Shoes doesn't support `finish` method.

=== hover { |self| ... } » self ===

The hover event happens when the mouse enters the slot.  The block gets `self`,
meaning the object which was hovered over.

To catch the mouse exiting the slot, check out the [[Events.leave]] event.

=== keypress { |key| ... } » self ===

Whenever a key (or combination of keys) is pressed, the block gets called.  The
block is sent a `key` which is a string representing the character (such as the
letter or number) on the key. 

So, for example, if `Shift-a` is pressed, the block will get the string `"Shift_L"` and `"A"`.

And if the `F1` key is pressed, the `"F1"` string is received. 

The left side modifier keys are `"Control_L"`, `"Shift_L"` and `"Alt_L"`.  They appear in that order.
If `Shift-Control-Alt-PgUp` is pressed, the strings will be
`"Shift_L"`, `"Control_L"`, `"Alt_L"` and `"Page_Up"`.

One thing about the shift key.  On
US keyboards, `Shift-7` is an ampersand.  So you'll get the string `"Shift_L"` and `"ampersand"` rather
than `"Shift_L"` and `"7"`.  And, if you press `Shift-Alt-7` on such a keyboard, you'll
get the strings: `"Shift_L"`, `"Alt_L"` and `"ampersand"`.  

{{{
 #!ruby
 Shoes.app do
   info = para "NO KEY is PRESSED."
   keypress do |k|
     info.replace "#{k.inspect} was PRESSED."
   end
 end
}}}


=== leave { |self| ... } » self ===

The leave event takes place when the mouse cursor exits a slot.  The moment it
no longer is inside the slot's edges.  When that takes place, the block is
called with `self`, the slot object which is being left.

Also see [[Events.hover]] if you'd like to detect the mouse entering a slot.

=== motion { |left, top| ... } » self ===

The motion block gets called every time the mouse moves around inside the slot.
The block is handed the cursor's `left` and `top` coordinates.

{{{
 #!ruby
 Shoes.app width: 200, height: 200 do
   background black
   fill white
   circ = oval 0, 0, 100, 100
 
   motion do |top, left|
     circ.move top - 50, left - 50
   end
 end
}}}

=== release { |button, left, top| ... } » self ===

The release block runs whenever the mouse is unclicked (on mouse up).  When the
finger is lifted.  The `button` is the number of the button that was depressed.
The `left` and `top` are the coordinates of the mouse at the time the button
was released.

To catch the actual mouse click, use the [[Events.click]] event.

=== start { |self| ... } » self ===

The first time the slot is drawn, the start event fires.  The block is handed
`self`, the slot object which has just been drawn.

'''Note:''' Green Shoes doesn't support `start` method.

== Manipulation Blocks ==

The manipulation methods below make quick work of shifting around slots and
inserting new elements.

=== append() { ... } » self ===

Adds elements to the end of a slot.

{{{
 #!ruby
 Shoes.app do
   @slot = stack { para 'Good Morning' }
   timer 3 do
     @slot.append do
       title "Breaking News"
       tagline "Astronauts ",
         "arrested for space shuttle DUI."
     end
   end
 end
}}}

The `title` and `tagline` elements will be added to the end of the `@slot`.

=== after(element) { ... } » self ===

Adds elements to a specific place in a slot, just after the `element` which is
a child of the slot.

=== before(element) { ... } » self ===

Adds elements to a specific place in a slot, just before the `element` which is
a child of the slot.

=== clear() » self ===

Empties the slot of any elements, timers and nested slots.  This is effectively
identical to looping through the contents of the slot and calling each
element's `remove` method.

=== clear() { ... } » self ===

The clear method also takes an optional block.  The block will be used to
replace the contents of the slot.

{{{
 #!ruby
 Shoes.app do
   @slot = stack { para "Old text" }
   timer 3 do
     @slot.clear { para "Brand new text" }
   end
 end
}}}

In this example, the "Old text" paragraph will be cleared out, replaced by the
"Brand new text" paragraph.

=== prepend() { ... } » self ===

Adds elements to the beginning of a slot.

{{{
 #!ruby
 Shoes.app do
   @slot = stack { para 'Good Morning' }
   timer 3 do
     @slot.prepend { para "Your car is ready." }
   end
 end
}}}

The `para` element is added to the beginning of the `@slot`.

== Position of a Slot ==

Like any other element, slots can be styled and customized when they are created.

To set the width of a stack to 150 pixels:

{{{
 #!ruby
 Shoes.app do
   stack width: 150 do
     background yellow
     para "Now that's precision." 
   end
 end
}}}

Each style setting also has a method, which can be used to grab that particular
setting.  (So, like, the `width` method returns the width of the slot in
pixels.)

=== displace(left: a number, top: a number) » self ===

A shortcut method for setting the :displace_left and :displace_top styles.
Displacing is a handy way of moving a slot without altering the layout.  In
fact, the `top` and `left` methods will not report displacement at all.  So,
generally, displacement is only for temporary animations.  For example,
jiggling a button in place.

The `left` and `top` numbers sent to `displace` are added to the slot's own
top-left coordinates.  To subtract from the top-left coordinate, use negative
numbers.

'''Note:''' Green Shoes doesn't support `displace` method.

=== gutter() » a number ===

The size of the scrollbar area.  When Shoes needs to show a scrollbar, the
scrollbar may end up covering up some elements that touch the edge of the
window.  The `gutter` tells you how many pixels to expect the scrollbar to
cover.

This is commonly used to pad elements on the right, like so:

{{{
 #!ruby
 # Not yet available
 Shoes.app do
   stack :margin_right => 20 + gutter do
     para "Insert fat and ratified ",
       "declaration of independence here..."
   end
 end
}}}

'''Note:''' Green Shoes doesn't support `gutter` method.

=== height() » a number ===

The vertical size of the viewable slot in pixels.  So, if this is a scrolling
slot, you'll need to use `scroll_height()` to get the full size of the slot.

=== hide() » self ===

Hides the slot, so that it can't be seen.  See also [[Position.show]] and [[Position.toggle]].

'''Note:''' Green Shoes doesn't support `hide` method.

=== left() » a number ===

The left pixel location of the slot.  Also known as the x-axis coordinate.

=== move(left, top) » self ===

Moves the slot to specific coordinates, the (left, top) being the upper left
hand corner of the slot.

'''Note:''' Green Shoes doesn't support `gutter` method.

=== remove() » self ===

Removes the slot. It will no longer be displayed and will not be listed in its
parent's contents. It's gone.

'''Note:''' Green Shoes doesn't support `remove` method. Use `clear` method.

=== scroll() » true or false ===

Is this slot allowed to show a scrollbar? True or false. The scrollbar will
only appear if the height of the slot is also fixed.

'''Note:''' Green Shoes doesn't support `scroll` method.

=== scroll_height() » a number ===

The vertical size of the full slot, including any of it which is hidden by scrolling.

'''Note:''' Green Shoes doesn't support `scroll_height` method.

=== scroll_max() » a number ===

The top coordinate which this slot can be scrolled down to.  The top coordinate
of a scroll bar is always zero.  The bottom coordinate is the full height of
the slot minus one page of scrolling.  This bottom coordinate is what
`scroll_max` returns.

This is basically a shortcut for writing `slot.scroll_height - slot.height`.

To scroll to the bottom of a slot, use `slot.scroll_top = slot.scroll_max`.

'''Note:''' Green Shoes doesn't support `scroll_max` method.

=== scroll_top() » a number ===

The top coordinate which this slot is scrolled down to.  So, if the slot is
scrolled down twenty pixels, this method will return `20`.

'''Note:''' Green Shoes doesn't support `scroll_top` method.

=== scroll_top = a number ===

Scrolls the slot to a certain coordinate.  This must be between zero and
`scroll_max`.

'''Note:''' Green Shoes doesn't support `scroll_top=` method.

=== show() » self ===

Reveals the slot, if it is hidden.  See also [[Position.hide]] and
[[Position.toggle]].

'''Note:''' Green Shoes doesn't support `show` method.

=== style() » styles ===

Calling the `style` method with no arguments returns a hash of the styles
presently applied to this slot.

While methods such as `height` and `width` return the true pixel dimensions of
the slot, you can use `style[:height]` or `style[:width]` to get the dimensions
originally requested.

{{{
 #!ruby
 Shoes.app do
   s = stack width: 1.0
   para s.style[:width]
   button('Then..'){s.append{para s.style[:width]}}
 end
}}}

In this example, the paragraph under the stack will display "1.0". 
After click the button, will show you "600" pixels.

=== style(styles) » styles ===

Alter the slot using a hash of style settings.  Any of the methods on this page
(aside from this method, of course) can be used as a style setting.  So, for
example, there is a `width` method, thus there is also a `width` style.

{{{
 #!ruby
 Shoes.app do
   s = stack { background green }
   s.style width: 400, height: 200
 end
}}}

=== toggle() » self ===

Hides the slot, if it is shown.  Or shows the slot, if it is hidden.

'''Note:''' Green Shoes doesn't support `toggle` method.

=== top() » a number ===

The top pixel location of the slot.  Also known as the y-axis coordinate.

=== width() » a number ===

The horizontal size of the slot in pixels.

== Traversing the Page ==

You may find yourself needing to loop through the elements inside a slot. Or
maybe you need to climb the page, looking for a stack that is the parent of an
element.

On any element, you may call the `parent` method to get the slot directly above
it. And on slots, you can call the `contents` method to get all of the
children. (Some elements, such as shapes, are not included in any slots.)

=== contents() » an array of elements ===

Lists all elements in a slot.

=== parent() » a Shoes::Stack or Shoes::Flow ===

Gets the object for this element's container.

{{{
 Shoes.app do
   s = stack do
     para 'Green'
     @p = para 'Shoes'
   end
   para s
   para s.contents
   para @p.parent
 end
}}}

= Elements =

Ah, here's the stuff of Green Shoes. An element can be as simple as an oval shape. Or
as complex as a para text string. You've encountered all of these elements before
in the Slots section of the manual.

Green Shoes has seven native controls: the Button, the EditLine, the EditBox, the
ListBox, the Progress meter, the Check box and the Radio.  By "native"
controls, we mean that each of these seven elements is drawn by Ruby/GTK2 apis 
directly.  So, a Progress bar will never convert to the PNG image data.

Greem Shoes also has seven basic other types of elements: Background, Border, Image,
Shape, TextBlock, Animate and Video.  These all should look and act the same on
every operating system.

Once an element is created, you will often still want to change it. To move it
or hide it or get rid of it. You'll use the commands in this section to do that
sort of stuff. (Especially check out the [[Common Common Methods]] section for
commands you can use on any element.)

So, for example, use the `image` method to place a PNG on the screen.
The `image` method gives you back an Image object. Use the methods of the Image
object to change things up.

== Common Methods ==

A few methods are shared by every little element in Green Shoes.  Moving, showing,
hiding.  Removing an element.  Basic and very general things.  This list
encompasses those common commands.

One of the most general methods of all is the `style` method (which is also
covered as the [[Position.style]] method for slots.)

{{{
 #!ruby
 Shoes.app do
   stack do
     # Background, text and a button: 
     # both are elements!
     @back  = background green
     @text  = banner "A Message for You, Rudy"
     @press = button "Stop your messin about!"
 
     # And so, both can be styled.
     @text.style size: 12, 
       markup: fg(@text.text, red), margin: 10
     @press.style width: 400
     @back.style height: 10
   end
 end
}}}

For specific commands, see the other links to the left in the Elements section.
Like if you want to pause or play a video file, check the [[Video]] section,
since pausing and playing is peculiar to videos.  No sense pausing a button.

'''Note:''' Green Shoes doesn't support `video` method.

=== displace(left: a number, top: a number) » self ===

Displacing an element moves it.  But without changing the layout around it.
This is great for subtle animations, especially if you want to reserve a place
for an element while it is still animating.  Like maybe a quick button shake or
a slot sliding into view.

When you displace an element, it moves relative to the upper-left corner where
it was placed.  So, if an element is at the coordinates (20, 40) and you
displace it 2 pixels left and 6 pixels on top, you end up with the coordinates
(22, 46).

{{{
 #!ruby
 # Not yet available
 Shoes.app do
   flow :margin => 12 do
     # Set up three buttons
     button "One"
     @two = button "Two"
     button "Three"
 
     # Bounce the second button
     animate do |i|
       @two.displace(0, (Math.sin(i) * 6).to_i)
     end
   end
 end
}}}

Notice that while the second button bounces, the other two buttons stay put.
If we used a normal `move` in this situation, the second button would be moved
out of the layout and the buttons would act as if the second button wasn't
there at all.  (See the [[Common.move]] example.)

'''Of particular note:''' if you use the `left` and `top` methods to get the
coordinates of a displaced element, you'll just get back the normal
coordinates.  As if there was no displacement.  Displacing is just intended for
quick animations!

'''Note:''' Green Shoes doesn't support `displace` method.

=== height() » a number ===

The vertical screen size of the element in pixels. In the case of images, this
is not the full size of the image. This is the height of the element as it is
shown right now.

If you have a 150x150 pixel image and you set the width to 50 pixels, this
method will return 50.

Also see the [[Common.width]] method for an example and some other comments.

=== hide() » self ===

Hides the element, so that it can't be seen.  See also [[Common.show]] and
[[Common.toggle]].

=== left() » a number ===

Gets you the pixel position of the left edge of the element.

=== move(left: a number, top: a number) » self  ===

Moves the element to a specific pixel position.  The element is no longer
inside the slot.  So, it will not be stacked or flowed in with the
other stuff in the slot.  The element will float freely, now absolutely
positioned instead.

{{{
 #!ruby
 Shoes.app do
   # Set up three buttons
   b = button "One"
   @two = button "Two"
   button "Three"
 
   # Bounce the second button
   animate do |i|
     @two.move(33, 33 + (Math.sin(i) * 6).to_i)
   end
 end
}}}

The second button is moved to a specific place, allowing the third button to
slide over into its place.  But it will not happen until you resize the window.
If you want to slide the third button without resizing the window, add `flush` method.

=== parent() » a Shoes::Stack or Shoes::Flow ===

Gets the object for this element's container.  Also see the slot's
[[Traversing.contents]] to do the opposite: get a container's elements.

=== remove() » self ===

Removes the element from its slot.  (In other words: throws it in the garbage.)
The element will no longer be displayed.

=== show() » self ===

Reveals the element, if it is hidden.  See also [[Common.hide]] and
[[Common.toggle]].

=== style() » styles ===

Gives you the full set of styles applied to this element, in the form of a
Hash.  While methods like `width` and `height` and `top` give you back specific
pixel dimensions, using `style[:width]` or `style[:top]`, you can get the
original setting (things like "100%" for width or "10px" for top.)

{{{
 #!ruby
 Shoes.app do
   # A button which take up the whole page
   @b = button "All of it", 
     width: width, height: height
 
   # When clicked, show the styles
   @b.click { alert(@b.style.inspect) }
 end
}}}

=== style(styles) » styles ===

Changes the style of an element.  This could include the `:width` and `:height`
of an element, the font `:size` of some text, the `:stroke` and `:fill` of a
shape.  Or any other number of style settings.

=== toggle() » self ===

Hides an element if it is shown.  Or shows the element, if it is hidden.

=== top() » a number ===

Gets the pixel position of the top edge of the element.

=== width() » a number ===

Gets the pixel width for the full size of the element.  This method always
returns an exact pixel size.  In the case of images, this is not the full width
of the image, just the size it is shown at.  See the [[Common.height]] method
for more.

Also, if you create an element with a width of 1.0 and that element is inside
a stack which is 120 pixels wide, you'll get back `120`.  And, if you call
`style[:width]`, you'll get `120`.

{{{
 #!ruby
 Shoes.app do
   stack width: 120 do
     @b = button "Click me", width: 1.0 do
       alert "button.width = #{@b.width}\n" +
         "button.style[:width] = " +
         "#{@b.style[:width]}"
     end
   end
 end
}}}

In order to set the width, you'll have to go through the [[Common.style]]
method again.  So, to set the button to 150 pixels wide: `@b.style(width: 150)`.

== Background ==

A background is a color, a gradient or an image that is painted across an
entire slot.  Both backgrounds and borders are a type of Shoes::Pattern.
!{:margin_left => 100}man-ele-background.png!

Even though it's called a ''background'', you may still place this element in
front of other elements.  If a background comes after something else painted on
the slot (like a `rect` or an `oval`,) the background will be painted over that
element.

The simplest background is just a plain color background, created with the
[[Element.background]] method, such as this black background:

{{{
 #!ruby
 Shoes.app do
   background black
 end
}}}

A simple background like that paints the entire slot that contains it.  (In
this case, the whole window is painted black.)

You can use styles to cut down the size or move around the background to your liking.

To paint a black background across the top fifty pixels of the window:

{{{
 #!ruby
 Shoes.app do
   background black, height: 50
 end
}}}

Or, to paint a fifty pixel column on the left-side of the window:

{{{
 #!ruby
 Shoes.app do
   background black, width: 50
 end
}}}

Since Backgrounds are normal elements as well, see also the start of the
[[Elements]] section for all of its other methods.

=== to_pattern() » a Shoes::Pattern ===

Yanks out the color, gradient or image used to paint this background and places
it in a normal Shoes::Pattern object.  You can then pass that object to other
backgrounds and borders.  Reuse it as you like.

'''Note:''' Green Shoes doesn't support `to_pattern` method.

== Border ==

A border is a color, gradient or image painted in a line around the edge of any
slot.  Like the Background element in the last section, a Border is a kind of
Shoes::Pattern. !{:margin_left => 100}man-ele-border.png!

The first, crucial thing to know about border is that all borders paint a line
around the '''inside''' of a slot, not the outside.  So, if you have a slot
which is fifty pixels wide and you paint a five pixel border on it, that means
there is a fourty pixel wide area inside the slot which is surrounded by the
border.

This also means that if you paint a Border on top of a [[Background]], the
edges of the background will be painted over by the border.

Here is just such a slot:

{{{
 #!ruby
 Shoes.app do
   stack width: 50 do
     border black, strokewidth: 5
     para fg "=^.^=", green
   end
 end
}}}

If you want to paint a border around the outside of a slot, you'll need to wrap
that slot in another slot.  Then, place the border in the outside slot.

{{{
 #!ruby
 Shoes.app do
   stack width: 60 do
     border black, strokewidth: 5
     stack width: 50 do
       para fg "=^.^=", green
     end
   end
 end
}}}

In HTML and many other languages, the border is painted on the outside of the
box, thus increasing the overall width of the box.  Green Shoes was designed with
consistency in mind, so that if you say that a box is fifty pixels wide, it
stays fifty pixels wide regardless of its borders or margins or anything else.

Please also check out the [[Elements]] section for other methods used on borders.

=== to_pattern() » a Shoes::Pattern ===

Creates a basic pattern object based on the color, gradient or image used to
paint this border.  The pattern may then be re-used in new borders and
backgrounds.

'''Note:''' Green Shoes doesn't support `to_pattern` method.

== Button ==

Buttons are, you know, push buttons.  You click them and they do something.
Buttons are known to say "OK" or "Are you sure?"  And, then, if you're sure,
you click the button. !{:margin_left => 100}man-ele-button.png!

{{{
 #!ruby
 Shoes.app do
   button "OK!"
   button "Are you sure?"
 end
}}}

The buttons in the example above don't do anything when you click them. In
order to get them to work, you've got to hook up a block to each button.

{{{
 #!ruby
 Shoes.app do
   button "OK!" do
     append { para "Well okay then." }
   end
   button "Are you sure?" do
     append { para "Your confidence is inspiring." }
   end
 end
}}}

So now we've got blocks for the buttons. Each block appends a new paragraph to
the page. The more you click, the more paragraphs get added.

It doesn't go much deeper than that. A button is just a clickable phrase.

Just to be pedantic, though, here's another way to write that last example.

{{{
 #!ruby
 Shoes.app do
   @b1 = button "OK!"
   @b1.click{para "Well okay then."}
   @b2 = button "Are you sure?"
   @b2.click{para "Your confidence is inspiring."}
 end
}}}

This looks dramatically different, but it does the same thing.  The first
difference: rather than attaching the block directly to the button, the block
is attached later, through the `click` method.

The second change isn't related to buttons at all.  The `append` block was
dropped since Green Shoes allows you to add new elements directly to the slot.  So we
can just call `para` directly.  (This isn't the case with the `prepend`,
`before` or `after` methods.)

Beside the methods below, buttons also inherit all of the methods that are
[[Common]].

=== click() { |self| ... } » self ===

When a button is clicked, its `click` block is called.  The block is handed
`self`.  Meaning: the button which was clicked.

=== focus() » self ===

Moves focus to the button.  The button will be highlighted and, if the user
hits Enter, the button will be clicked.

'''Note:''' Green Shoes doesn't support `focus` method.

== Check ==

Check boxes are clickable square boxes than can be either checked or unchecked.
A single checkbox usually asks a "yes" or "no" question.  Sets of checkboxes
are also seen in to-do lists. !{:margin_left => 100}man-ele-check.png!

Here's a sample checklist.

{{{
 #!ruby
 Shoes.app do
   stack do
     flow do
       check; para "Frances Johnson", width: 200
     end
     flow do
       check; para "Ignatius J. Reilly", width: 200
     end
     flow do
       check
       para "Winston Niles Rumfoord", width: 200
     end
   end
 end
}}}

You basically have two ways to use a check.  You can attach a block to the
check and it'll get called when the check gets clicked.  And/or you can just
use the `checked?` method to go back and see if a box has been checked or not.

Okay, let's add to the above example.

{{{
 #!ruby
 Shoes.app do
   @list = ['Frances Johnson', 'Ignatius J. Reilly',
     'Winston Niles Rumfoord']
 
   stack do
     @list.map! do |name|
       flow { @c = check; para name, width: 200 }
       [@c, name]
     end
 
     button "What's been checked?" do
       selected = 
         @list.map{|c, n| n if c.checked?}.compact
       alert("You selected: " + selected.join(', '))
     end
   end
 end
}}}

So, when the button gets pressed, each of the checks gets asked for its status,
using the `checked?` method.

Button methods are listed below, but also see the list of [[Common]] methods,
which all elements respond to.

=== checked?() » true or false ===

Returns whether the box is checked or not.  So, `true` means "yes, the box is checked!"

=== checked = true or false ===

Marks or unmarks the check box.  Using `checked = false`, for instance,
unchecks the box.

=== click() { |self| ... } » self ===

When the check is clicked, its `click` block is called.  The block is handed
`self`, which is the check object which was clicked.

Clicks are sent for both checking and unchecking the box.

=== focus() » self ===

Moves focus to the check.  The check will be highlighted and, if the user hits
Enter, the check will be toggled between its checked and unchecked states.

'''Note:''' Green Shoes doesn't support `focus` method.

== EditBox ==

Edit boxes are wide, rectangular boxes for entering text.  On the web, they
call these textareas.  These are multi-line edit boxes for entering longer
descriptions.  Essays, even! !{:margin_left => 100}man-ele-editbox.png!

Without any other styling, edit boxes are sized 200 pixels by 108 pixels.  You
can also use `:width` and `:height` styles to set specific sizes.

{{{
 #!ruby
 Shoes.app do
   edit_box
   edit_box width: 100, height: 100
 end
}}}

Other controls (like [[Button]] and [[Check]]) have only click events, but both
[[EditLine]] and EditBox have a `change` event.  The `change` block is called
every time someone types into or deletes from the box.

{{{
 #!ruby
 Shoes.app do
   edit_box do |e|
     @counter.text = 
       strong("#{e.text.size}") + " characters"
   end
   @counter = para strong("0"), " characters"
 end
}}}

Notice that the example also uses the [[EditBox.text]] method inside the block.
That method gives you a string of all the characters typed into the box.

More edit box methods are listed below, but also see the list of [[Common]]
methods, which all elements respond to.

=== change() { |self| ... } » self ===

Each time a character is added to or removed from the edit box, its `change`
block is called. The block is given `self`, which is the edit box object which
has changed.

=== focus() » self ===

Moves focus to the edit box. The edit box will be highlighted and the user will
be able to type into the edit box.

'''Note:''' Green Shoes doesn't support `focus` method.

=== text() » self ===

Return a string of characters which have been typed into the box.

=== text = a string ===

Fills the edit box with the characters of `a string`.

== EditLine ==

Edit lines are a slender, little box for entering text. While the EditBox is
multi-line, an edit line is just one. Line, that is. Horizontal, in fact.
!{:margin_left => 100}man-ele-editline.png!

The unstyled edit line is 200 pixels wide and 28 pixels wide. Roughly. The
height may vary on some platforms.

{{{
 #!ruby
 Shoes.app do
   stack do
     edit_line
     edit_line width: 400
   end
 end
}}}

You can change the size by styling both the `:width` and the `:height`.
However, you generally only want to style the `:width`, as the height will be
sized to fit the font. (And, in current versions of Green Shoes, the font for edit
lines and edit boxes cannot be altered anyway.)

If a block is given to an edit line, it receives `change` events. Check out the
[[EditBox]] page for an example of using a change block. In fact, the edit box
has all the same methods as an edit line. Also see the list of [[Common]]
methods, which all elements respond to.

=== change() { |self| ... } » self ===

Each time a character is added to or removed from the edit line, its `change`
block is called. The block is given `self`, which is the edit line object which
has changed.

=== focus() » self ===

Moves focus to the edit line. The edit line will be highlighted and the user
will be able to type into the edit line.

'''Note:''' Green Shoes doesn't support `focus` method.

=== text() » self ===

Return a string of characters which have been typed into the box.

=== text = a string ===

Fills the edit line with the characters of `a string`.

== Image ==

An image is a picture in PNG, JPEG or GIF format. Green Shoes can resize images or
flow them in with text. Images can be loaded from a file or directly off the
web. !{:margin_left => 100}man-ele-image.png!

To create an image, use the `image` method in a slot:

{{{
 #!ruby
 Shoes.app do
   para "Nice, nice, very nice.  Busy, busy, busy."
   image File.join DIR,
     "../static/shoes-manual-apps.png"
  end
}}}

When you load any image into Green Shoes, it is cached in memory. This means that if
you load up many image elements from the same file, it'll only really load the
file once.

You can use web URLs directly as well.

{{{
 #!ruby
 Shoes.app do
   image "http://is.gd/c0mBtb"
 end
}}}

When an image is loaded from the web, it's cached on the hard drive as well as
in memory. This prevents a repeat download unless the image has changed. (In
case you're wondering: Shoes keeps track of modification times and etags just
like a browser would.)

'''Note:''' Green Shoes doesn't support the hard drive cache management feature like Red Shoes.

Green Shoes also loads remote images in the background using system threads. So,
using remote images will not block Ruby or any intense graphical displays you
may have going on.

=== full_height() » a number ===

The full pixel height of the image. Normally, you can just use the
[[Common.height]] method to figure out how many pixels high the image is. But
if you've resized the image or styled it to be larger or something, then
`height` will return the scaled size.

The `full_height` method gives you the height of image (in pixels) as it was
stored in the original file.

=== full_width() » a number ===

The full pixel width of the image. See the [[Image.full_height]] method for an
explanation of why you might use this method rather than [[Common.width]].

=== path() » a string ===

The URL or file name of the image.

'''Note:''' Green Shoes doesn't support `path` method.

=== path = a string ===

Swaps the image with a different one, loaded from a file or URL.

'''Note:''' Green Shoes doesn't support `path=` method.

== ListBox ==

List boxes (also called "combo boxes" or "drop-down boxes" or "select boxes" in
some places) are a list of options that drop down when you click on the box.
!{:margin_left => 100}man-ele-listbox.png!

A list box gets its options from an array.  An array (a list) of strings,
passed into the `:items` style.

{{{
 #!ruby
 Shoes.app do
   para "Choose a fruit:"
   list_box items: ["Grapes", "Pears", "Apricots"]
 end
}}}

So, the basic size of a list box is about 200 pixels wide and 28 pixels high.
You can adjust this length using the `:width` style.

{{{
 #!ruby
 Shoes.app do
   para "Choose a fruit:"
   list_box items: ["Grapes", "Pears", "Apricots"],
     width: 120, choose: "Apricots" do |list|
       @fruit.text = list.text
   end
 
   @fruit = para "No fruit selected"
 end
}}}

Next to the `:width` style, the example uses another useful option. The
`:choose` option tells the list box which of the items should be highlighted
from the beginning. (There's also a [[ListBox.choose]] method for highlighting
an item after the box is created.)

List boxes also have a [[ListBox.change]] event. In the last example, we've got
a block hooked up to the list box. Well, okay, see, that's a `change` block.
The block is called each time someone changes the selected item.

Those are the basics. Might you also be persuaded to look at the [[Common]]
methods page, a complete list of the methods that all elements have?

=== change() { |self| ... } » self ===

Whenever someone highlights a new option in the list box (by clicking on an
item, for instance,) its `change` block is called. The block is given `self`,
which is the list box object which has changed.

=== choose(item: a string) » self ===

Selects the option in the list box that matches the string given by `item`.

=== focus() » self ===

Moves focus to the list box. The list box will be highlighted and, if the user
hits the up and down arrow keys, other options in the list will be selected.

'''Note:''' Green Shoes doesn't support `focus` method.

=== items() » an array of strings ===

Returns the complete list of strings that the list box presently shows as its options.

=== items = an array of strings ===

Replaces the list box's options with a new list of strings.

=== text() » a string ===

A string containing whatever text is shown highlighted in the list box right
now. If nothing is selected, `nil` will be the reply.

== Progress ==

Progress bars show you how far along you are in an activity. Usually, a
progress bar represents a percentage (from 0% to 100%.) Green Shoes thinks of
progress in terms of the decimal numbers 0.0 to 1.0. !{:margin_left =>
100}man-ele-progress.png!

A simple progress bar is 150 pixels wide, but you can use the `:width` style
(as with all Green Shoes elements) to lengthen it.

'''Note:''' The minimum size is 150 pixels wide in Green Shoes.

{{{
 Shoes.app do
   title "Progress example"
   @p = progress left: 10, top: 100, width: width-20
 
   animate do |i|
     @p.fraction = (i % 100) / 100.0
   end
 end
}}}

Take a look at the [[Common]] methods page for a list of methods found an all
elements, including progress bars.

=== fraction() » a decimal number ===

Returns a decimal number from 0.0 to 1.0, indicating how far along the progress bar is.

=== fraction = a decimal number ===

Sets the progress to a decimal number between 0.0 and 1.0.

== Radio ==

Radio buttons are a group of clickable circles. Click a circle and it'll be
marked. Only one radio button can be marked at a time. (This is similar to the
ListBox, where only one option can be selected at a time.) !{:margin_left =>
100}man-ele-radio.png!

So, how do you decide when to use radio buttons and when to use list boxes?
Well, list boxes only show one highlighted item unless you click on the box and
the drop-down appears. But radio buttons are all shown, regardless of which is
marked.

{{{
 #!ruby
 Shoes.app do
   para "Among these films, which do you prefer?\n"
   radio
   para strong("The Taste of Tea"), 
     " by Katsuhito Ishii\n", width: 570
   radio
   para strong("Kin-Dza-Dza"), 
     " by Georgi Danelia\n", width: 570
   radio
   para strong("Children of Heaven"), 
     " by Majid Majidi\n", width: 570
 end
}}}

Only one of these three radios can be checked at a time, since they are grouped
together in the same slot (along with a bunch of `para`.)

If we move them each into their own slot, the example breaks.

{{{
 #!ruby
 Shoes.app do
   stack do
     para "Among these films, which do you prefer?"
     flow do
       radio
       para "The Taste of Tea by Katsuhito Ishii", 
         width: 300
     end
     flow do
       radio
       para "Kin-Dza-Dza by Georgi Danelia",
         width: 300
     end
     flow do
       radio
       para "Children of Heaven by Majid Majidi",
         width: 300
     end
   end
 end
}}}

This can be fixed, though. You can group together radios from different slots,
you just have to give them all the same group name.

Here, let's group all these radios in the `:films` group.

{{{
 #!ruby
 Shoes.app do
   stack do
     para "Among these films, which do you prefer?"
     flow do
       radio :films
       para "The Taste of Tea by Katsuhito Ishii",
         width: 300
     end
     flow do
       radio :films
       para "Kin-Dza-Dza by Georgi Danelia",
         width: 300
     end
     flow do
       radio :films
       para "Children of Heaven by Majid Majidi",
         width: 300
     end
   end
 end
}}}

For more methods beyond those listed below, also look into the [[Common]]
methods page. Because you get those methods on every radio as well.

=== checked?() » true or false ===

Returns whether the radio button is checked or not. So, `true` means "yes, it
is checked!"

=== checked = true or false ===

Marks or unmarks the radio button. Using `checked = false`, for instance,
clears the radio.

=== click() { |self| ... } » self ===

When the radio button is clicked, its `click` block is called. The block is
handed `self`, which is an object representing the radio which was clicked.

Clicks are sent for both marking and unmarking the radio.

=== focus() » self ===

Moves focus to the radio. The radio will be highlighted and, if the user hits
Enter, the radio will be toggled between its marked and unmarked states.

'''Note:''' Green Shoes doesn't support `focus` method.

== Shape ==

A shape is a path outline usually created by drawing methods like `oval` and
`rect`. !{:margin_left => 100}man-ele-shape.png!

See the [[Common]] methods page.  Shapes respond to all of those methods.

== TextBlock ==

The TextBlock object represents a group of text organized as a single element.
A paragraph containing bolded text, for example. A caption containing links and
bolded text. (So, a `caption` is a TextBlock type.  However, `link` and
`strong` are Text types.) !{:margin_left => 100}man-ele-textblock.png!

All of the various types of TextBlock are found on the [[Element Element
Creation]] page.

 * [[Element.banner]], a 48 pixel font.
 * [[Element.title]], a 34 pixel font.
 * [[Element.subtitle]], a 26 pixel font.
 * [[Element.tagline]], an 18 pixel font.
 * [[Element.caption]], a 14 pixel font.
 * [[Element.para]], a 12 pixel font.
 * [[Element.inscription]], a 10 pixel font.

=== contents() » an array of elements  ===

Lists all of the strings and styled text objects inside this block.

'''Note:''' Green Shoes doesn't support `contents` method.

=== replace(a string) ===

Replaces the text of the entire block with the characters of `a string`.

=== text() » a string ===

Return a string of all of the characters in this text box. This will strip off
any style or text classes and just return the actual characters, as if seen on
the screen.

=== text = a string ===

Replaces the text of the entire block with the characters of `a string`.

=== to_s() » a string ===

An alias for [[TextBlock.text]]. Returns a flattened string of all of this
TextBlock's contents.

'''Note:''' Green Shoes doesn't support `to_s` method.

=== cursor() » an index ===

Return a text cursor position. That is an index of the text which is a string
of all of the characters in this text box.

=== cursor = an index or nil ===

Shows or hides the text cursor.
Using `cursor = 3`, for instance, shows the text cursor at index 3 from the front.
Using `cursor = -1` shows the text cursor at the end of the text.
Using `cursor = nil` hides the text cursor.

{{{
 Shoes.app do
  msg = para 'hello ' * 20
  msg.cursor = -1
  keypress do |k|
    n = case k
      when 'Left'; -1
      when 'Right'; 1
      else
        next
    end
    n += msg.cursor
    len = msg.text.length
    n = len unless n > -1
    msg.cursor = n % (len+1)
    flush
  end
 end
}}}

== Timers ==

Green Shoes contains three timers: the animate, every and
timer. Both animate and every loop over and over after they
start.  The timer happens once. A one-shot timer.

The animate and every are basically the same thing. The difference is that
the animate usually happen many, many times per second. And the every happens only
once every few seconds or rarely.

The animate and every automatically start themselves.

=== start() » self ===

Both types of timers automatically start themselves, so there's no need to use
this normally. But if you [[Timers.stop]] a timer and would like to start it up
again, then by all means: use this!

'''Note:''' Green Shoes doesn't support `start` method.

=== stop() » self ===

Stops the animate or every loop.

=== pause() » self ===

Pauses the animate or every loop. If the animate or every loop is stopped, it is started. Otherwise, if it is
already running, it is stopped.

== Video ==

Shoes supports embedding of QuickTime, Flash video (FLV), DivX, Xvid and
various other popular video formats. This is all thanks to VideoLAN and ffmpeg,
two sensational open source libraries. Use the `video` method on a slot to
setup a Shoes::Video object. 

'''Note:''' Green Shoes doesn't support any video formats. !{:margin_left => 100}man-ele-video.png!

In addition to video formats, some audio formats are also supported, such as
MP3, WAV and Ogg Vorbis.

Video support is optional in Shoes and some builds do not support video. For
example, video support is unavailable for PowerPC. When you download Shoes, the
build for your platform will be marked `novideo` in the filename if no video
support is available.

=== hide() » self ===

Hides the video. If already playing, the video will continue to play. This just
turns off display of the video. One possible use of this method is to collapse
the video area when it is playing an audio file, such as an MP3.

=== length() » a number ===

The full length of the video in milliseconds. Returns nil if the video is not
yet loaded.

=== move(left, top) » self ===

Moves the video to specific coordinates, the (left, top) being the upper left
hand corner of the video.

=== pause() » self ===

Pauses the video, if it is playing.

=== playing?() » true of false ===

Returns true if the video is currently playing. Or, false if the video is
paused or stopped.

=== play() » self ===

Starts playing the video, if it isn't already playing. If already playing, the
video is restarted from the beginning.

=== position() » a decimal ===

The position of the video as a decimanl number (a Float) between the beginning
(0.0) and the end (1.0). For instance, a Float value of 0.5 indicates the
halfway point of the video.

=== position = a decimal ===

Sets the position of the video using a Float value. To move the video to its
25% position: `@video.position = 0.25`.

=== remove() » self ===

Removes the video from its slot. This will stop the video as well.

=== show() » self ===

Reveals the video, if it has been hidden by the `hide()` method.

=== stop() » self ===

Stops the video, if it is playing.

=== time() » a number ===

The time position of the video in milliseconds. So, if the video is 10 seconds
into play, this method would return the number 10000.

=== time = a number ===

Set the position of the video to a time in milliseconds.

=== toggle() » self ===

Toggles the visibility of the video. If the video can be seen, then `hide` is
called. Otherwise, `show` is called.

= AndSoForth =

A place for some other information. 

== Sample Apps ==

Have fun!

{SAMPLES}

== FAQ ==

Hope this helps:

 * You can join [[http://librelist.com/browser/shoes/ Shoes ML]] and feel free ask your questions. 
 * [[https://github.com/ashbb/green_shoes/ Current Source Code]] is on GitHub.
 * Green Shoes Gem is on [[http://rubygems.org/gems/green_shoes RubyGems.org]].