# [](https://github.com/AndyObtiva/glimmer) Glimmer DSL for SWT 4.17.10.8
## JRuby Desktop Development GUI Framework
[![Gem Version](https://badge.fury.io/rb/glimmer-dsl-swt.svg)](http://badge.fury.io/rb/glimmer-dsl-swt)
[![Travis CI](https://travis-ci.com/AndyObtiva/glimmer-dsl-swt.svg?branch=master)](https://travis-ci.com/github/AndyObtiva/glimmer-dsl-swt)
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[![Maintainability](https://api.codeclimate.com/v1/badges/aaf1cba142dd351f84bd/maintainability)](https://codeclimate.com/github/AndyObtiva/glimmer-dsl-swt/maintainability)
[![Join the chat at https://gitter.im/AndyObtiva/glimmer](https://badges.gitter.im/AndyObtiva/glimmer.svg)](https://gitter.im/AndyObtiva/glimmer?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
**[Contributors Wanted! (Submit a Glimmer App Sample to Get Started)](#contributing)**
(The Original Glimmer Library Since 2007. Beware of Imitators!)
[Glimmer DSL for SWT](https://github.com/AndyObtiva/glimmer) is a native-GUI cross-platform desktop development library written in [JRuby](https://www.jruby.org/), an OS-threaded faster version of [Ruby](https://www.ruby-lang.org/en/). [Glimmer](https://github.com/AndyObtiva/glimmer)'s main innovation is a declarative [Ruby DSL](#glimmer-dsl-syntax) that enables productive and efficient authoring of desktop application user-interfaces while relying on the robust [Eclipse SWT library](https://www.eclipse.org/swt/). [Glimmer](https://rubygems.org/gems/glimmer) additionally innovates by having built-in [data-binding](#data-binding) support, which greatly facilitates synchronizing the GUI with domain models, thus achieving true decoupling of object oriented components and enabling developers to solve business problems (test-first) without worrying about GUI concerns. To get started quickly, [Glimmer](https://rubygems.org/gems/glimmer) offers [scaffolding](#scaffolding) options for [Apps](#in-production), [Gems](#custom-shell-gem), and [Custom Widgets](#custom-widgets). [Glimmer](https://rubygems.org/gems/glimmer) also includes native-executable [packaging](#packaging--distribution) support, sorely lacking in other libraries, thus enabling the delivery of desktop apps written in [Ruby](https://www.ruby-lang.org/en/) as truly native DMG/PKG/APP files on the [Mac](https://www.apple.com/ca/macos) + [App Store](https://developer.apple.com/macos/distribution/), MSI/EXE files on [Windows](https://www.microsoft.com/en-ca/windows), and [Gem Packaged Shell Scripts](#custom-shell-gem) on [Linux](https://www.linux.org/).
[Glimmer receives two updates per month](https://rubygems.org/gems/glimmer-dsl-swt/versions). You can trust [Glimmer](https://rubygems.org/gems/glimmer) with your Ruby desktop GUI development needs. Please make [Glimmer](https://rubygems.org/gems/glimmer) even better by providing feedback and [contributing](#contributing) when possible.
Gem version numbers are in sync with the SWT library versions. The first two digits represent the SWT version number. The last two digits represent the minor and patch versions of Glimmer DSL for SWT.
[Glimmer DSL for SWT](https://rubygems.org/gems/glimmer-dsl-swt) versions 4.17.x.y come with [SWT 4.17](https://download.eclipse.org/eclipse/downloads/drops4/R-4.17-202009021800/), which was released on September 2, 2020.
[
Featured in
JRuby Cookbook](http://shop.oreilly.com/product/9780596519650.do)
Glimmer DSL gems:
- [glimmer-dsl-swt](https://github.com/AndyObtiva/glimmer-dsl-swt): Glimmer DSL for SWT (JRuby Desktop GUI)
- [glimmer-dsl-tk](https://github.com/AndyObtiva/glimmer-dsl-tk): Glimmer DSL for Tk (Ruby Desktop GUI)
- [glimmer-dsl-opal](https://github.com/AndyObtiva/glimmer-dsl-opal): Glimmer DSL for Opal (Web GUI Adapter for Desktop Apps)
- [glimmer-dsl-xml](https://github.com/AndyObtiva/glimmer-dsl-xml): Glimmer DSL for XML (& HTML)
- [glimmer-dsl-css](https://github.com/AndyObtiva/glimmer-dsl-css): Glimmer DSL for CSS
## Examples
### Hello, World!
Glimmer code (from [samples/hello/hello_world.rb](samples/hello/hello_world.rb)):
```ruby
include Glimmer
shell {
text "Glimmer"
label {
text "Hello, World!"
}
}.open
```
Run via `glimmer samples` or directly:
```
glimmer samples/hello/hello_world.rb
```
Glimmer app:
![Hello World](images/glimmer-hello-world.png)
### Tic Tac Toe
Glimmer code (from [samples/elaborate/tic_tac_toe.rb](samples/elaborate/tic_tac_toe.rb)):
```ruby
# ...
@shell = shell {
text "Tic-Tac-Toe"
minimum_size 150, 178
composite {
grid_layout 3, true
(1..3).each { |row|
(1..3).each { |column|
button {
layout_data :fill, :fill, true, true
text bind(@tic_tac_toe_board[row, column], :sign)
enabled bind(@tic_tac_toe_board[row, column], :empty)
font style: :bold, height: 20
on_widget_selected {
@tic_tac_toe_board.mark(row, column)
}
}
}
}
}
}
# ...
```
Run via `glimmer samples` or directly:
```
glimmer samples/elaborate/tic_tac_toe.rb
```
Glimmer app:
![Tic Tac Toe](images/glimmer-tic-tac-toe-in-progress.png)
### Contact Manager
Glimmer code (from [samples/elaborate/contact_manager.rb](samples/elaborate/contact_manager.rb)):
```ruby
# ...
shell {
text "Contact Manager"
composite {
group {
grid_layout(2, false) {
margin_width 0
margin_height 0
}
layout_data :fill, :center, true, false
text 'Lookup Contacts'
font height: 24
label {
layout_data :right, :center, false, false
text "First &Name: "
font height: 16
}
text {
layout_data :fill, :center, true, false
text bind(@contact_manager_presenter, :first_name)
on_key_pressed {|key_event|
@contact_manager_presenter.find if key_event.keyCode == swt(:cr)
}
}
label {
layout_data :right, :center, false, false
text "&Last Name: "
font height: 16
}
text {
layout_data :fill, :center, true, false
text bind(@contact_manager_presenter, :last_name)
on_key_pressed {|key_event|
@contact_manager_presenter.find if key_event.keyCode == swt(:cr)
}
}
label {
layout_data :right, :center, false, false
text "&Email: "
font height: 16
}
text {
layout_data :fill, :center, true, false
text bind(@contact_manager_presenter, :email)
on_key_pressed {|key_event|
@contact_manager_presenter.find if key_event.keyCode == swt(:cr)
}
}
composite {
row_layout {
margin_width 0
margin_height 0
}
layout_data(:right, :center, false, false) {
horizontal_span 2
}
button {
text "&Find"
on_widget_selected { @contact_manager_presenter.find }
on_key_pressed {|key_event|
@contact_manager_presenter.find if key_event.keyCode == swt(:cr)
}
}
button {
text "&List All"
on_widget_selected { @contact_manager_presenter.list }
on_key_pressed {|key_event|
@contact_manager_presenter.list if key_event.keyCode == swt(:cr)
}
}
}
}
table(:multi) { |table_proxy|
layout_data {
horizontal_alignment :fill
vertical_alignment :fill
grab_excess_horizontal_space true
grab_excess_vertical_space true
height_hint 200
}
table_column {
text "First Name"
width 80
}
table_column {
text "Last Name"
width 80
}
table_column {
text "Email"
width 200
}
items bind(@contact_manager_presenter, :results),
column_properties(:first_name, :last_name, :email)
on_mouse_up { |event|
table_proxy.edit_table_item(event.table_item, event.column_index)
}
}
}
}.open
# ...
```
Run via `glimmer samples` or directly:
```
glimmer samples/elaborate/contact_manager.rb
```
Glimmer App:
![Contact Manager](images/glimmer-contact-manager.png)
### Desktop Apps Built with Glimmer DSL for SWT
[Are We There Yet?](https://github.com/AndyObtiva/are-we-there-yet) - Small Project Tracking App
[![Are We There Yet? App Screenshot](https://raw.githubusercontent.com/AndyObtiva/are-we-there-yet/master/are-we-there-yet-screenshot-windows.png)](https://github.com/AndyObtiva/are-we-there-yet)
[Math Bowling](https://github.com/AndyObtiva/MathBowling) - Elementary Level Math Game Featuring Bowling Rules
[![Math Bowling App Screenshot](https://raw.githubusercontent.com/AndyObtiva/MathBowling/master/Math-Bowling-Screenshot.png)](https://github.com/AndyObtiva/MathBowling)
## Table of contents
- [Glimmer (JRuby Desktop Development GUI Framework)](#jruby-desktop-development-gui-framework)
- [Examples](#examples)
- [Hello, World!](#hello-world)
- [Tic Tac Toe](#tic-tac-toe)
- [Contact Manager](#contact-manager)
- [Desktop Apps Built with Glimmer DSL for SWT](#desktop-apps-built-with-glimmer-dsl-for-swt)
- [Table of contents](#table-of-contents)
- [Background](#background)
- [Platform Support](#platform-support)
- [Pre-requisites](#pre-requisites)
- [Setup](#setup)
- [Option 1: Direct Install](#option-1-direct-install)
- [Option 2: Bundler](#option-2-bundler)
- [Glimmer Command](#glimmer-command)
- [Basic Usage](#basic-usage)
- [Advanced Usage](#advanced-usage)
- [Glimmer Samples](#glimmer-samples)
- [Scaffolding](#scaffolding)
- [App](#app)
- [Desktopify](#desktopify)
- [Custom Shell](#custom-shell)
- [Custom Widget](#custom-widget)
- [Custom Shell Gem](#custom-shell-gem)
- [Custom Widget Gem](#custom-widget-gem)
- [Gem Listing](#gem-listing)
- [Listing Custom Shell Gems](#listing-custom-shell-gems)
- [Listing Custom Widget Gems](#listing-custom-widget-gems)
- [Listing DSL Gems](#listing-dsl-gems)
- [Packaging](#packaging)
- [Raw JRuby Command](#raw-jruby-command)
- [Mac Support](#mac-support)
- [Girb (Glimmer irb) Command](#girb-glimmer-irb-command)
- [Glimmer GUI DSL Syntax](#glimmer-gui-dsl-syntax)
- [DSL Auto-Expansion](#dsl-auto-expansion)
- [Widgets](#widgets)
- [SWT Proxies](#swt-proxies)
- [Dialog](#dialog)
- [Display](#display)
- [Multi-Threading](#multi-threading)
- [Menus](#menus)
- [ScrolledComposite](#scrolledcomposite)
- [Widget Styles](#widget-styles)
- [Explicit SWT Style Bit](#explicit-swt-style-bit)
- [Negative SWT Style Bits](#negative-swt-style-bits)
- [Extra SWT Styles](#extra-swt-styles)
- [Widget Properties](#widget-properties)
- [Color](#color)
- [Font](#font)
- [Image](#image)
- [Image Options](#image-options)
- [Cursor](#cursor)
- [Layouts](#layouts)
- [Layout Data](#layout-data)
- [Data-Binding](#data-binding)
- [General Examples](#general-examples)
- [Combo](#combo)
- [List](#list)
- [Table](#table)
- [Tree](#tree)
- [DateTime](#datetime)
- [Observer](#observer)
- [Observing Widgets](#observing-widgets)
- [Observing Models](#observing-models)
- [Custom Widgets](#custom-widgets)
- [Simple Example](#simple-example)
- [Custom Widget Lifecycle Hooks](#custom-widget-lifecycle-hooks)
- [Lifecycle Hooks Example](#lifecycle-hooks-example)
- [Custom Widget API](#custom-widget-api)
- [Content/Options Example](#contentoptions-example)
- [Gotcha](#gotcha)
- [Final Notes](#final-notes)
- [Custom Shells](#custom-shells)
- [Drag and Drop](#drag-and-drop)
- [Miscellaneous](#miscellaneous)
- [Multi-DSL Support](#multi-dsl-support)
- [Application Menu Items (About/Preferences)](#application-menu-items-aboutpreferences)
- [App Name and Version](#app-name-and-version)
- [Checkbox Group Widget](#checkbox-group-widget)
- [Radio Group Widget](#radio-group-widget)
- [Code Text Widget](#code-text-widget)
- [Video Widget](#video-widget)
- [Sash Form Widget](#sash-form-widget)
- [Browser Widget](#browser-widget)
- [Glimmer Configuration](#glimmer-configuration)
- [logger](#logger)
- [logging_devices](#loggingdevices)
- [logging_device_file_options](#loggingdevicefileoptions)
- [logging_appender_options](#loggingappenderoptions)
- [logging_layout](#logginglayout)
- [import_swt_packages](#importswtpackages)
- [loop_max_count](#loopmaxcount)
- [excluded_keyword_checkers](#excludedkeywordcheckers)
- [log_excluded_keywords](#logexcludedkeywords)
- [Glimmer Style Guide](#glimmer-style-guide)
- [SWT Reference](#swt-reference)
- [Samples](#samples)
- [Hello Samples](#hello-samples)
- [Hello, World! Sample](#hello-world-sample)
- [Hello, Tab!](#hello-tab)
- [Hello, Combo!](#hello-combo)
- [Hello, List Single Selection!](#hello-list-single-selection)
- [Hello, List Multi Selection!](#hello-list-multi-selection)
- [Hello, Computed!](#hello-computed)
- [Hello, Message Box!](#hello-message-box)
- [Hello, Browser!](#hello-browser)
- [Hello, Drag and Drop!](#hello-drag-and-drop)
- [Hello, Menu Bar!](#hello-menu-bar)
- [Hello, Pop Up Context Menu!](#hello-pop-up-context-menu)
- [Hello, Custom Widget!](#hello-custom-widget)
- [Hello, Custom Shell!](#hello-custom-shell)
- [Hello, Sash Form!](#hello-sash-form)
- [Hello, Styled Text!](#hello-styled-text)
- [Hello, Expand Bar!](#hello-expand-bar)
- [Hello, Radio!](#hello-radio)
- [Hello, Radio Group!](#hello-radio-group)
- [Hello, Group!](#hello-group)
- [Hello, Checkbox!](#hello-checkbox)
- [Hello, Checkbox Group!](#hello-checkbox-group)
- [Hello, Directory Dialog!](#hello-directory-dialog)
- [Hello, File Dialog!](#hello-file-dialog)
- [Hello, Date Time!](#hello-date-time)
- [Hello, Spinner!](#hello-spinner)
- [Hello, Table!](#hello-table)
- [Hello, Button!](#hello-button)
- [Hello, Link!](#hello-link)
- [Elaborate Samples](#elaborate-samples)
- [User Profile](#user-profile)
- [Login](#login)
- [Tic Tac Toe Sample](#tic-tac-toe-sample)
- [Contact Manager Sample](#contact-manager-sample)
- [External Samples](#external-samples)
- [Glimmer Calculator](#glimmer-calculator)
- [Gladiator](#gladiator)
- [Timer](#timer)
- [In Production](#in-production)
- [Math Bowling](#math-bowling)
- [Are We There Yet?](#are-we-there-yet)
- [Garderie Rainbow Daily Agenda](#garderie-rainbow-daily-agenda)
- [Packaging & Distribution](#packaging--distribution)
- [Packaging Defaults](#packaging-defaults)
- [Packaging Configuration](#packaging-configuration)
- [javapackager Extra Arguments](#javapackager-extra-arguments)
- [Verbose Mode](#verbose-mode)
- [Windows Application Packaging](#windows-application-packaging)
- [Mac Application Distribution](#mac-application-distribution)
- [Self Signed Certificate](#self-signed-certificate)
- [Gotchas](#gotchas)
- [App Updates](#app-updates)
- [Glimmer Supporting Libraries](#glimmer-supporting-libraries)
- [Glimmer Process](#glimmer-process)
- [Resources](#resources)
- [Help](#help)
- [Issues](#issues)
- [Chat](#chat)
- [Feature Suggestions](#feature-suggestions)
- [Change Log](#change-log)
- [Contributing](#contributing)
- [Contributors](#contributors)
- [Hire Me](#hire-me)
- [License](#license)
## Background
Ruby is a dynamically-typed object-oriented language, which provides great productivity gains due to its powerful expressive syntax and dynamic nature. While it is proven by the Ruby on Rails framework for web development, it currently lacks a robust platform-independent framework for building desktop applications. Given that Java libraries can now be utilized in Ruby code through JRuby, Eclipse technologies, such as SWT, JFace, and RCP can help fill the gap of desktop application development with Ruby.
## Platform Support
Glimmer runs on the following platforms:
- Mac
- Windows
- Linux
Glimmer's GUI has the native look and feel of each operating system it runs on since it uses SWT behind the scenes, which leverages the following native libraries:
- Win32 on Windows
- Cocoa on Mac
- GTK on Linux
More info about the SWT GUI on various platforms can be found on the Eclipse WIKI and SWT FAQ:
https://wiki.eclipse.org/SWT/Devel/Gtk/Dev_guide#Win32.2FCocoa.2FGTK
https://www.eclipse.org/swt/faq.php
## Pre-requisites
- JDK 8u241 (1.8.0_241) (find at https://www.oracle.com/java/technologies/javase/javase8u211-later-archive-downloads.html)
- JRuby 9.2.13.0 (supporting Ruby 2.5.x syntax) (get via [RVM](http://rvm.io) on Mac and Linux or find at [https://www.jruby.org/download](https://www.jruby.org/download) for Windows)
- SWT 4.17 (already included in the [glimmer-dsl-swt](https://rubygems.org/gems/glimmer-dsl-swt) gem)
To obtain JRuby through [RVM](http://rvm.io), you may run:
```bash
rvm install jruby-9.2.13.0
```
Glimmer might still work on other versions of Java, JRuby and SWT, but there are no guarantees, so it is best to stick to the pre-requisites outlined above.
## Setup
Please follow these instructions to make the `glimmer` command available on your system via the [`glimmer-dsl-swt`](https://github.com/AndyObtiva/glimmer-dsl-swt) gem.
If you intend to learn the basics of Glimmer but are not ready to build a Glimmer app yet, pick Option 1 ([Direct Install](#option-1-direct-install)).
If you intend to build a Glimmer app from scratch with [scaffolding](#scaffolding), pick Option 1 ([Direct Install](#option-1-direct-install)) as well.
Otherwise, Option 2 ([Bundler](#option-2-bundler)) can be followed in rare cases where you want to build an app without [scaffolding](#scaffolding).
Note: if you encounter any [issues](https://github.com/AndyObtiva/glimmer-dsl-swt/issues), please [report](https://github.com/AndyObtiva/glimmer-dsl-swt/issues) and then install a previous version instead from the list of [Glimmer Releases](https://rubygems.org/gems/glimmer-dsl-swt/versions).
### Option 1: Direct Install
(Use for [Scaffolding](#scaffolding))
Run this command to install directly:
```
jgem install glimmer-dsl-swt
```
Or this command if you want a specific version:
```
jgem install glimmer-dsl-swt -v 4.17.10.8
```
`jgem` is JRuby's version of `gem` command.
RVM allows running `gem install` directly as an alias.
Otherwise, you may also run `jruby -S gem install ...`
If you are new to Glimmer and would like to continue learning the basics, you may continue to the [Glimmer Command](https://github.com/AndyObtiva/glimmer#glimmer-command) section.
Otherwise, if you are ready to build a Glimmer app, you can jump to the [Glimmer Scaffolding](https://github.com/AndyObtiva/glimmer#scaffolding) section next.
Note: if you're using activerecord or activesupport, keep in mind that Glimmer unhooks ActiveSupport::Dependencies as it does not rely on it.
### Option 2: Bundler
(Use for Manual App Creation)
Add the following to `Gemfile`:
```
gem 'glimmer-dsl-swt', '~> 4.17'
```
And, then run:
```
jruby -S bundle install
```
Note: if you're using activerecord or activesupport, keep in mind that Glimmer unhooks ActiveSupport::Dependencies as it does not rely on it.
You may learn more about other Glimmer related gems ([`glimmer-dsl-opal`](https://github.com/AndyObtiva/glimmer-dsl-opal), [`glimmer-dsl-xml`](https://github.com/AndyObtiva/glimmer-dsl-xml), and [`glimmer-dsl-css`](https://github.com/AndyObtiva/glimmer-dsl-css)) at [Multi-DSL Support](#multi-dsl-support)
## Glimmer Command
The `glimmer` command allows you to run, scaffold, package, and list Glimmer applications/gems.
You can bring up usage instructions by running the `glimmer` command without arguments:
```
glimmer
```
On Mac and Linux, it additionally brings up a TUI (Text-based User Interface) for interactive navigation and execution of Glimmer tasks (courtesy of [rake-tui](https://github.com/AndyObtiva/rake-tui)).
On Windows, it simply lists the available Glimmer tasks at the end (courtsey of [rake](https://github.com/ruby/rake)).
If you are new to Glimmer, you may read the Basic Usage section and skip the rest until you have gone through [Girb (Glimmer irb) Command](#girb-glimmer-irb-command), [Glimmer GUI DSL Syntax](#glimmer-gui-dsl-syntax), and [Samples](#samples).
Note: If you encounter an issue running the `glimmer` command, run `bundle exec glimmer` instead.
### Basic Usage
```
glimmer application.rb
```
Runs a Glimmer application using JRuby, automatically preloading
the glimmer ruby gem and SWT jar dependency.
Run Glimmer samples with:
```
glimmer samples
```
This brings up the [Glimmer Meta-Sample (The Sample of Samples)](#samples)
If you cloned this project locally instead of installing the gem, run `bin/glimmer` instead.
Example:
```
bin/glimmer samples
```
### Advanced Usage
Below are the full usage instructions that come up when running `glimmer` without args.
```
Glimmer (JRuby Desktop Development GUI Framework) - JRuby Gem: glimmer-dsl-swt v4.17.10.8
Usage: glimmer [--bundler] [--pd] [--quiet] [--debug] [--log-level=VALUE] [[ENV_VAR=VALUE]...] [[-jruby-option]...] (application.rb or task[task_args]) [[application2.rb]...]
Runs Glimmer applications and tasks.
When applications are specified, they are run using JRuby,
automatically preloading the glimmer Ruby gem and SWT jar dependency.
Optionally, extra Glimmer options, JRuby options, and/or environment variables may be passed in.
Glimmer options:
- "--bundler=GROUP" : Activates gems in Bundler default group in Gemfile
- "--pd=BOOLEAN" : Requires puts_debuggerer to enable pd method
- "--quiet=BOOLEAN" : Does not announce file path of Glimmer application being launched
- "--debug" : Displays extra debugging information, passes "--debug" to JRuby, and enables debug logging
- "--log-level=VALUE" : Sets Glimmer's Ruby logger level ("ERROR" / "WARN" / "INFO" / "DEBUG"; default is none)
Tasks are run via rake. Some tasks take arguments in square brackets.
Available tasks are below (if you do not see any, please add `require 'glimmer/rake_task'` to Rakefile and rerun or run rake -T):
Select a Glimmer task to run: (Press ↑/↓ arrow to move, Enter to select and letters to filter)
‣ glimmer list:gems:customshell[query] # List Glimmer custom shell gems available at rubygems.org (query is optional) [alt: list:gems:cs]
glimmer list:gems:customwidget[query] # List Glimmer custom widget gems available at rubygems.org (query is optional) [alt: list:gems:cw]
glimmer list:gems:dsl[query] # List Glimmer DSL gems available at rubygems.org (query is optional)
glimmer package[type] # Package app for distribution (generating config, jar, and native files) (type is optional)
glimmer package:clean # Clean by removing "dist" and "packages" directories
glimmer package:config # Generate JAR config file
glimmer package:gemspec # Generate gemspec
glimmer package:jar # Generate JAR file
glimmer package:lock_jars # Lock JARs
glimmer package:native[type] # Generate Native files
glimmer run[app_path] # Runs Glimmer app or custom shell gem in the current directory, unless app_path is specified, then runs it instead (app_path is optional)
glimmer samples # Brings up the Glimmer Meta-Sample app to allow browsing, running, and viewing code of Glimmer samples
glimmer scaffold[app_name] # Scaffold Glimmer application directory structure to build a new app
glimmer scaffold:customshell[name,namespace] # Scaffold Glimmer::UI::CustomShell subclass (full window view) under app/views (namespace is optional) [alt: scaffold:cs]
glimmer scaffold:customwidget[name,namespace] # Scaffold Glimmer::UI::CustomWidget subclass (part of a view) under app/views (namespace is optional) [alt: scaffold:cw]
glimmer scaffold:gem:customshell[name,namespace] # Scaffold Glimmer::UI::CustomShell subclass (full window view) under its own Ruby gem + app project (namespace is required) [alt: scaffold:ge...
glimmer scaffold:gem:customwidget[name,namespace] # Scaffold Glimmer::UI::CustomWidget subclass (part of a view) under its own Ruby gem project (namespace is required) [alt: scaffold:gem:cw]
```
Example (Glimmer/JRuby option specified):
```
glimmer --debug samples/hello/hello_world.rb
```
Runs Glimmer application with JRuby debug option to enable JRuby debugging.
Example (Multiple apps):
```
glimmer samples/hello/hello_world.rb samples/hello/hello_tab.rb
```
Launches samples/hello/hello_world.rb and samples/hello_tab.rb at the same time, each in a separate JRuby thread.
### Glimmer Samples
You can list available Glimmer samples by running:
```
glimmer samples
```
This brings up the [Glimmer Meta-Sample (The Sample of Samples)](#samples):
![Glimmer Meta-Sample](images/glimmer-meta-sample.png)
### Scaffolding
Glimmer borrows from Rails the idea of Scaffolding, that is generating a structure for your app files that
helps you get started just like true building scaffolding helps construction workers, civil engineers, and architects.
Glimmer scaffolding goes beyond just scaffolding the app files that Rails does. It also packages it and launches it,
getting you to a running and delivered state of an advanced "Hello, World!" Glimmer application right off the bat.
This should greatly facilitate building a new Glimmer app by helping you be productive and focus on app details while
letting Glimmer scaffolding take care of initial app file structure concerns, such as adding:
- Main application class that includes Glimmer (`app/{app_name}.rb`)
- Main application view that houses main window content, menu, about dialog, and preferences dialog
- View and Model directories (`app/views` and `app/models`)
- Rakefile including Glimmer tasks (`Rakefile`)
- Version (`VERSION`)
- License (`LICENSE.txt`)
- Icon (under `package/{platform}/{App Name}.{icon_extension}` for `macosx` .icns, `windows` .ico, and `linux` .png)
- Bin file for starting application (`bin/{app_name}.rb`)
You need to have your Git `user.name` and `github.user` configured before scaffolding since Glimmer uses Juwelier, which relies on them in creating a Git repo for your Glimmer app.
#### App
Before you start, make sure you are in a JRuby environment with Glimmer gem installed as per "Direct Install" pre-requisites.
To scaffold a Glimmer app from scratch, run the following command:
```
glimmer scaffold[AppName]
```
This will generate an advanced "Hello, World!" app, package it as a Mac DMG/PKG/APP, Windows APP, or Linux GEM, and launch it all in one fell swoop.
Suppose you run:
```
glimmer scaffold[greeter]
```
You should see output like the following:
```
$ glimmer scaffold[greeter]
create .gitignore
create Rakefile
create Gemfile
create LICENSE.txt
create README.rdoc
create .document
create lib
create lib/greeter.rb
create spec
create spec/spec_helper.rb
create spec/greeter_spec.rb
create .rspec
Juwelier has prepared your gem in ./greeter
Created greeter/.gitignore
Created greeter/.ruby-version
Created greeter/.ruby-gemset
Created greeter/VERSION
Created greeter/LICENSE.txt
Created greeter/Gemfile
Created greeter/Rakefile
Created greeter/app/greeter.rb
Created greeter/app/views/greeter/app_view.rb
Created greeter/package/windows/Greeter.ico
Created greeter/package/macosx/Greeter.icns
Created greeter/package/linux/Greeter.png
Created greeter/bin/greeter
Created greeter/spec/spec_helper.rb
...
```
Eventually, it will launch an advanced "Hello, World!" app window having the title of your application ("Greeter").
![Glimmer Scaffold App](images/glimmer-scaffolding-app.png)
It also comes with a boilerplate Preferences dialog.
![Glimmer Scaffold App Preferences](images/glimmer-scaffolding-app-preferences.png)
Here is the Windows version of the scaffolded "Greeter" app:
![Glimmer Scaffold App Windows](images/glimmer-scaffolding-app-windows.png)
And, here is the Windows version of the boilerplate Preferences dialog.
![Glimmer Scaffold App Windows Preferences](images/glimmer-scaffolding-app-windows-preferences.png)
In order to run the app after making changes, you must run the `glimmer run`. It automatically detects the generated run script under the `bin` directory and uses it as an argument.
```
glimmer run
```
Alternatively, to mantually run the app, you may type:
```
glimmer run[bin/greeter]
```
or:
```
glimmer bin/greeter
```
#### Desktopify
Desktopify basically turns a website into a desktop application by wrapping the website within a [Browser Widget](#browser-widget).
The desktopify app is similar to the standard scaffolded app. It can be extended and the [browser may even be instrumented](https://help.eclipse.org/2020-09/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/browser/Browser.html).
The app even remembers your cookies if you log into the website, close the app, and reopen again.
Note that on Linux, the default SWT browser, which runs on webkit, does not support HTML5 Video out of the box. If you need video support, open `Gemfile` after scaffolding and enable the line that has the `glimmer-cw-browser-chromium` gem then replace the `browser` in "app/views/snowboard_utah/app_view.rb" with `browser(:chromium)`
Before you start, make sure you are in a JRuby environment with Glimmer gem installed as per "Direct Install" pre-requisites.
To scaffold a Glimmer desktopify app from scratch, run the following command:
```
glimmer scaffold:desktopify[app_name,website]
```
This will generate a Glimmer app, package it as a Mac DMG/PKG/APP, Windows APP, or Linux GEM, and launch it all in one fell swoop.
Suppose you run:
```
glimmer scaffold:desktopify[snowboard_utah,https://www.brightonresort.com]
```
You should see output like the following:
```
$ glimmer scaffold:desktopify[snowboard_utah,https://www.brightonresort.com]
Fetching kamelcase-0.0.2.gem
Fetching github_api-0.19.0.gem
Fetching highline-2.0.3.gem
Fetching juwelier-2.4.9.gem
Fetching hashie-3.6.0.gem
Fetching nokogiri-1.10.10-java.gem
Fetching semver2-3.4.2.gem
Successfully installed semver2-3.4.2
Successfully installed kamelcase-0.0.2
Successfully installed highline-2.0.3
Successfully installed hashie-3.6.0
Successfully installed github_api-0.19.0
Successfully installed nokogiri-1.10.10-java
Successfully installed juwelier-2.4.9
7 gems installed
create .gitignore
create Rakefile
create Gemfile
create LICENSE.txt
create README.markdown
create .document
create lib
create lib/snowboard_utah.rb
create .rspec
Juwelier has prepared your gem in ./snowboard_utah
Created snowboard_utah/.gitignore
Created snowboard_utah/.ruby-version
Created snowboard_utah/.ruby-gemset
Created snowboard_utah/VERSION
Created snowboard_utah/LICENSE.txt
Created snowboard_utah/Gemfile
Created snowboard_utah/Rakefile
Created snowboard_utah/app/snowboard_utah.rb
Created snowboard_utah/app/views/snowboard_utah/app_view.rb
Created snowboard_utah/package/windows/Snowboard Utah.ico
Created snowboard_utah/package/macosx/Snowboard Utah.icns
Created snowboard_utah/package/linux/Snowboard Utah.png
Created snowboard_utah/bin/snowboard_utah
...
```
Eventually, it will launch a desktopified version of "https://www.brightonresort.com" having the title of ("Snowboard Utah").
Desktopified App on Mac
![Glimmer Scaffold App](images/glimmer-scaffolding-desktopify.png)
It also comes with a boilerplate About dialog.
![Glimmer Scaffold App About](images/glimmer-scaffolding-desktopify-about.png)
Desktopified App on Windows
![Glimmer Scaffold App](images/glimmer-scaffolding-desktopify-windows.png)
Desktopified App on Linux
![Glimmer Scaffold App](images/glimmer-scaffolding-desktopify-linux.png)
In order to run the app after making changes, you must run the `glimmer run`. It automatically detects the generated run script under the `bin` directory and uses it as an argument.
```
glimmer run
```
#### Custom Shell
To scaffold a Glimmer custom shell (full window view) for an existing Glimmer app, run the following command:
```
glimmer scaffold:customshell[name]
```
Or the following alternative abbreviation:
```
glimmer scaffold:cs[name]
```
#### Custom Widget
To scaffold a Glimmer custom widget (part of a view) for an existing Glimmer app, run the following command:
```
glimmer scaffold:customwidget[name]
```
Or the following alternative abbreviation:
```
glimmer scaffold:cw[name]
```
#### Custom Shell Gem
Custom shell gems are self-contained Glimmer apps as well as reusable custom shells.
They have everything scaffolded Glimmer apps come with in addition to gem content like a [Juwelier](https://rubygems.org/gems/juwelier) Rakefile that can build gemspec and release gems.
Unlike scaffolded Glimmer apps, custom shell gem content lives under the `lib` directory (not `app`).
They can be packaged as both a native executable (e.g. Mac DMG/PKG/APP) and a Ruby gem.
Of course, you can just build a Ruby gem and disregard native executable packaging if you do not need it.
To scaffold a Glimmer custom shell gem (full window view distributed as a Ruby gem), run the following command:
```
glimmer scaffold:gem:customshell[name,namespace]
```
Or the following alternative abbreviation:
```
glimmer scaffold:gem:cs[name,namespace]
```
It is important to specify a namespace to avoid having your gem clash with existing gems.
The Ruby gem name will follow the convention "glimmer-cs-customwidgetname-namespace" (the 'cs' is for Custom Shell).
Only official Glimmer gems created by the Glimmer project committers will have no namespace (e.g. [glimmer-cs-gladiator](https://rubygems.org/gems/glimmer-cs-gladiator) Ruby gem)
Since custom shell gems are both an app and a gem, they provide two ways to run:
- Run the `glimmer` command and pass it the generated script under the `bin` directory that matches the gem name (e.g. run `glimmer bin/glimmer-cs-calculator`)
- Run the executable shell script that ships with the gem directly (does not need the `glimmer` command). It intentionally has a shorter name for convenience since it is meant to be used on the command line (not in a package), so you can leave out the `glimmer-cs-` prefix (e.g. run `bin/calculator` directly). This is also used as the main way of running custom shell gems on Linux.
Examples:
- [glimmer-cs-gladiator](https://github.com/AndyObtiva/glimmer-cs-gladiator): Gladiator (Glimmer Editor)
- [glimmer-cs-calculator](https://github.com/AndyObtiva/glimmer-cs-calculator): Glimmer Calculator
#### Custom Widget Gem
To scaffold a Glimmer custom widget gem (part of a view distributed as a Ruby gem), run the following command:
```
glimmer scaffold:gem:customwidget[name,namespace]
```
Or the following alternative abbreviation:
```
glimmer scaffold:gem:cw[name,namespace]
```
It is important to specify a namespace to avoid having your gem clash with existing gems.
The Ruby gem name will follow the convention "glimmer-cw-customwidgetname-namespace" (the 'cw' is for Custom Widget)
Only official Glimmer gems created by the Glimmer project committers will have no namespace (e.g. [glimmer-cw-video](https://rubygems.org/gems/glimmer-cw-video) Ruby gem)
Examples:
- [glimmer-cw-video](https://github.com/AndyObtiva/glimmer-cw-video): Video Widget
- [glimmer-cw-cdatetime-nebula](https://github.com/AndyObtiva/glimmer-cw-cdatetime-nebula): Nebula CDateTime Widget
### Gem Listing
The `glimmer` command comes with tasks for listing Glimmer related gems to make it easy to find Glimmer Custom Shells, Custom Widgets, and DSLs published by others in the Glimmer community on [rubygems.org](http://www.rubygems.org).
#### Listing Custom Shell Gems
The following command lists available Glimmer [Custom Shell Gems](#custom-shell-gem) (prefixed with "glimmer-cs-" by scaffolding convention) created by the the Glimmer community and published on [rubygems.org](http://www.rubygems.org):
```
glimmer list:gems:customshell[query]
```
Or the following alternative abbreviation:
```
glimmer list:gems:cs[query]
```
Example:
```
glimmer list:gems:cs
```
Output:
```
Glimmer Custom Shell Gems at rubygems.org:
Name Gem Version Author Description
Calculator glimmer-cs-calculator 1.0.2 Andy Maleh Calculator - Glimmer Custom Shell
Gladiator glimmer-cs-gladiator 0.2.4 Andy Maleh Gladiator (Glimmer Editor) - Glimmer Custom Shell
Timer glimmer-cs-timer 1.0.0 Andy Maleh Timer - Glimmer Custom Shell
```
#### Listing Custom Widget Gems
The following command lists available Glimmer [Custom Widget Gems](#custom-widget-gem) (prefixed with "glimmer-cw-" by scaffolding convention) created by the the Glimmer community and published on [rubygems.org](http://www.rubygems.org):
```
glimmer list:gems:customwidget[query]
```
Or the following alternative abbreviation:
```
glimmer list:gems:cw[query]
```
Example:
Check if there is a custom video widget for Glimmer.
```
glimmer list:gems:cw[video]
```
Output:
```
Glimmer Custom Widget Gems matching [video] at rubygems.org:
Name Gem Version Author Description
Video glimmer-cw-video 1.0.0 Andy Maleh Glimmer Custom Widget - Video
```
Example:
Check all custom widgets for Glimmer.
```
glimmer list:gems:cw
```
Output:
```
Glimmer Custom Widget Gems at rubygems.org:
Name Gem Version Author Description
Browser (Chromium) glimmer-cw-browser-chromium 1.0.0 Andy Maleh Chromium Browser - Glimmer Custom Widget
Cdatetime (Nebula) glimmer-cw-cdatetime-nebula 1.5.0.0.1 Andy Maleh Nebula CDateTime Widget - Glimmer Custom Widget
Video glimmer-cw-video 1.0.0 Andy Maleh Glimmer Custom Widget - Video
```
#### Listing DSL Gems
The following command lists available Glimmer [DSL Gems](#multi-dsl-support) (prefixed with "glimmer-dsl-" by convention) created by the the Glimmer community and published on [rubygems.org](http://www.rubygems.org):
```
glimmer list:gems:dsl[query]
```
Example:
```
glimmer list:gems:dsl
```
Output:
```
Glimmer DSL Gems at rubygems.org:
Name Gem Version Author Description
Css glimmer-dsl-css 1.1.0 AndyMaleh Glimmer DSL for CSS
Opal glimmer-dsl-opal 0.8.0 AndyMaleh Glimmer DSL for Opal
Swt glimmer-dsl-swt 4.17.10.8
AndyMaleh Glimmer DSL for SWT
Tk glimmer-dsl-tk 0.0.6 AndyMaleh Glimmer DSL for Tk
Xml glimmer-dsl-xml 1.1.0 AndyMaleh Glimmer DSL for XML
```
### Packaging
Glimmer supports packaging applications as native files on Mac and Windows.
Glimmer packaging tasks are detailed under [Packaging & Distribution](#packaging--distribution).
On Linux, the Glimmer [Custom Shell Gem](#custom-shell-gem) approach provides a [Gem Packaged Shell Script](#custom-shell-gem) (e.g. `calculator` command becomes available after installing the [glimmer-cs-calculator](https://github.com/AndyObtiva/glimmer-cs-calculator) gem)
### Raw JRuby Command
If there is a need to run Glimmer directly via the `jruby` command, you
may run the following on Windows/Linux:
```
jruby -r glimmer-dsl-swt -S application.rb
```
Or, the following on Mac:
```
jruby -J-XstartOnFirstThread -r glimmer-dsl-swt -S application.rb
```
If you want to use a specific custom version of SWT, run the following on Windows/Linux:
```
jruby -J-classpath "path_to/swt.jar" -r glimmer-dsl-swt -S application.rb
```
Or, the following on Mac:
```
jruby -J-XstartOnFirstThread -J-classpath "path_to/swt.jar" -r glimmer-dsl-swt -S application.rb
```
The `-J-classpath` option specifies the `swt.jar` file path, which can be a
manually downloaded version of SWT, or otherwise the one included in the gem. You can lookup the one included in the gem by running `jgem which glimmer` to find the gem path and then look through the `vendor` directory.
The `-r` option preloads (requires) the `glimmer` library in Ruby.
The `-S` option specifies a script to run.
#### Mac Support
The Mac is well supported with the `glimmer` command. The advice below is not needed if you are using it.
However, if there is a reason to use the raw `jruby` command directly instead of the `glimmer` command, you need to pass an extra option (`-J-XstartOnFirstThread`) to JRuby on the Mac (Glimmer automatically passes it for you when using the `glimmer` command).
Example:
```
jruby -J-XstartOnFirstThread -J-classpath "path_to/swt.jar" -r glimmer-dsl-swt -S application.rb
```
## Girb (Glimmer irb) Command
With `glimmer-dsl-swt` installed, you may want to run `girb` instead of standard `irb` to have SWT preloaded and the Glimmer library required and included for quick Glimmer coding/testing.
```
girb
```
If you cloned [glimmer-dsl-swt](https://github.com/AndyObtiva/glimmer-dsl-swt) project locally, you may run `bin/girb` instead.
```
bin/girb
```
Watch out for hands-on examples in this README indicated by "you may copy/paste in [`girb`](#girb-glimmer-irb-command)"
Keep in mind that all samples live under [https://github.com/AndyObtiva/glimmer-dsl-swt](https://github.com/AndyObtiva/glimmer-dsl-swt)
## Glimmer GUI DSL Syntax
Glimmer's core is a GUI DSL with a lightweight visual syntax that makes it easy to visualize the nesting of widgets in the GUI hierarchy tree.
It is available through mixing in the `Glimmer` module, which makes Glimmer GUI DSL keywords available to both the instance scope and class scope:
```ruby
include Glimmer
```
For example, here is the basic "Hello, World!" sample code (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
include Glimmer
shell {
text "Glimmer"
label {
text "Hello, World!"
}
}.open
```
The `include Glimmer` declaration on top mixed the `Glimmer` module into the Ruby global main object making the Glimmer GUI DSL available at the top-level global scope.
While this works well enough for mini-samples, it is better to isolate Glimmer in a class or module during production application development to create a clean separation between view code (GUI) and model code (business domain). Here is the "Hello, World!" sample re-written in a class to illustrate how mixing in the `Glimmer` module (via `include Glimmer`) makes the Glimmer GUI DSL available in both the instance scope and class scope. That is clearly demonstrated by pre-initializing a color constant in the class scope and building the GUI in the `#open` instance method (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
class HelloWorld
include Glimmer # makes the GUI DSL available in both the class scope and instance scope
COLOR_FOREGROUND_DEFAULT = rgb(255, 0, 0) # rgb is a GUI DSL keyword used in the class scope
def open
# the following are GUI DSL keywords (shell, text, and label) used in the instance scope
shell {
text "Glimmer"
label {
text "Hello, World!"
foreground COLOR_FOREGROUND_DEFAULT
}
}.open
end
end
HelloWorld.new.open
```
This renders "Hello, World!" with a red foreground color:
![Hello World Red Foreground Color](images/glimmer-hello-world-red-foreground-color.png)
The GUI DSL intentionally avoids overly verbose syntax, requiring as little declarative code as possible to describe what GUI to render, how to style it, and what properties to data-bind to the Models.
As such, it breaks off from Ruby's convention of using `do end` for multi-line blocks, opting instead for the lightweight and visual `{ }` curly brace blocks everywhere inside the GUI DSL. More details about Glimmer's syntax conventions may be found in the [Glimmer Style Guide](#glimmer-style-guide)
Glimmer DSL syntax consists mainly of:
- keywords (e.g. `table` for a table widget)
- style/args (e.g. :multi as in `table(:multi)` for a multi-line selection table widget)
- content (e.g. `{ table_column { text 'Name'} }` as in `table(:multi) { table_column { text 'name'} }` for a multi-line selection table widget with a table column having header text property `'Name'` as content)
### DSL Auto-Expansion
Glimmer supports a new and radical Ruby DSL concept called DSL Auto-Expansion. To explain, let's first mention the two types of Glimmer GUI DSL keywords: static and dynamic.
Static keywords are pre-identified keywords in the Glimmer DSL, such as `shell`, `display`, `message_box`, `async_exec`, `sync_exec`, and `bind`.
Dynamic keywords are dynamically figured out from currently imported (aka required/loaded) SWT widgets and custom widgets. Examples are: `label`, `combo`, and `list` for SWT widgets and `c_date_time`, `video`, and `gantt_chart` for custom widgets.
The only reason to distinguish between the two is to realize that importing new Glimmer [custom widgets](#custom-widgets) and Java SWT custom widget libraries automatically expands Glimmer's DSL vocabulary with new dynamic keywords.
For example, if a project adds this custom Java SWT library from the [Nebula Project](https://www.eclipse.org/nebula/):
https://www.eclipse.org/nebula/widgets/gallery/gallery.php
Glimmer will automatically support using the keyword `gallery`
This is what DSL Auto-Expansion is.
You will learn more about widgets next.
### Widgets
Glimmer GUIs (user interfaces) are modeled with widgets, which are wrappers around the SWT library widgets found here:
https://www.eclipse.org/swt/widgets/
This screenshot taken from the link above should give a glimpse of how SWT widgets look and feel:
[![SWT Widgets](images/glimmer-swt-widgets.png)](https://www.eclipse.org/swt/widgets/)
In Glimmer DSL, widgets are declared with lowercase underscored names mirroring their SWT names minus the package name. For example, here are some Glimmer widgets and their SWT counterparts:
- `shell` instantiates `org.eclipse.swt.widgets.Shell`
- `text` instantiates `org.eclipse.swt.widgets.Text`
- `button` instantiates `org.eclipse.swt.widgets.Button`
- `label` instantiates `org.eclipse.swt.widgets.Label`
- `composite` instantiates `org.eclipse.swt.widgets.Composite`
- `tab_folder` instantiates `org.eclipse.swt.widgets.TabFolder`
- `tab_item` instantiates `org.eclipse.swt.widgets.TabItem`
- `table` instantiates `org.eclipse.swt.widgets.Table`
- `table_column` instantiates `org.eclipse.swt.widgets.TableColumn`
- `tree` instantiates `org.eclipse.swt.widgets.Tree`
- `combo` instantiates `org.eclipse.swt.widgets.Combo`
- `list` instantiates `org.eclipse.swt.widgets.List`
Every **widget** is sufficiently declared by name, but may optionally be accompanied with:
- SWT **style**/***arguments*** wrapped by parenthesis according to [Glimmer Style Guide](#glimmer-style-guide) (see [next section](#widget-styles) for details).
- Ruby block containing **content**, which may be **properties** (e.g. `enabled false`) or nested **widgets** (e.g. `table_column` nested inside `table`)
For example, if we were to revisit `samples/hello/hello_world.rb` above (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
shell {
text "Glimmer"
label {
text "Hello, World!"
}
}.open
```
Note that `shell` instantiates the outer shell **widget**, in other words, the window that houses all of the desktop graphical user interface.
`shell` is then followed by a ***block*** that contains
```ruby
# ...
text "Glimmer" # text property of shell
label { # label widget declaration as content of shell
text "Hello, World!" # text property of label
}
# ...
```
The first line declares a **property** called `text`, which sets the title of the shell (window) to `"Glimmer"`. **Properties** always have ***arguments*** (not wrapped by parenthesis according to [Glimmer Style Guide](#glimmer-style-guide)), such as the text `"Glimmer"` in this case, and do **NOT** have a ***block*** (this distinguishes them from **widget** declarations).
The second line declares the `label` **widget**, which is followed by a Ruby **content** ***block*** that contains its `text` **property** with value `"Hello, World!"`
The **widget** ***block*** may optionally receive an argument representing the widget proxy object that the block content is for. This is useful in rare cases when the content code needs to refer to parent widget during declaration. You may leave that argument out most of the time and only add when absolutely needed.
Example:
```ruby
shell {|shell_proxy|
#...
}
```
Remember that The `shell` widget is always the outermost widget containing all others in a Glimmer desktop windowed application.
After it is declared, a `shell` must be opened with the `#open` method, which can be called on the block directly as in the example above, or by capturing `shell` in a `@shell` variable (shown in example below), and calling `#open` on it independently (recommended in actual apps)
```ruby
@shell = shell {
# properties and content
# ...
}
@shell.open
```
It is centered upon initial display and has a minimum width of 130 (can be re-centered when needed with `@shell.center` method after capturing `shell` in a `@shell` variable as per samples)
Check out the [samples](samples) directory for more examples.
Example from [hello_tab.rb](samples/hello/hello_tab.rb) sample (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
![Hello Tab English](images/glimmer-hello-tab-english.png)
![Hello Tab French](images/glimmer-hello-tab-french.png)
```ruby
shell {
text "Hello, Tab!"
tab_folder {
tab_item {
text "English"
label {
text "Hello, World!"
}
}
tab_item {
text "French"
label {
text "Bonjour Univers!"
}
}
}
}.open
```
If you are new to Glimmer, you have learned enough to start running some [samples](#samples). Go ahead and run all Glimmer [samples](#samples), and come back to read the rest in any order you like since this material is more organized like a reference.
If you are advanced and need more widgets, check out the [Nebula Project](https://www.eclipse.org/nebula/) for an extensive list of high quality custom widgets:
https://www.eclipse.org/nebula/
#### SWT Proxies
Glimmer follows Proxy Design Pattern by having Ruby proxy wrappers for all SWT objects:
- `Glimmer::SWT:WidgetProxy` wraps all descendants of `org.eclipse.swt.widgets.Widget` except the ones that have their own wrappers.
- `Glimmer::SWT::ShellProxy` wraps `org.eclipse.swt.widgets.Shell`
- `Glimmer::SWT:TabItemProxy` wraps `org.eclipse.swt.widget.TabItem` (also adds a composite to enable adding content under tab items directly in Glimmer)
- `Glimmer::SWT:LayoutProxy` wraps all descendants of `org.eclipse.swt.widget.Layout`
- `Glimmer::SWT:LayoutDataProxy` wraps all layout data objects
- `Glimmer::SWT:DisplayProxy` wraps `org.eclipse.swt.widget.Display` (manages displaying GUI)
- `Glimmer::SWT:ColorProxy` wraps `org.eclipse.swt.graphics.Color`
- `Glimmer::SWT:FontProxy` wraps `org.eclipse.swt.graphics.Font`
- `Glimmer::SWT::WidgetListenerProxy` wraps all widget listeners
These proxy objects have an API and provide some convenience methods, some of which are mentioned below.
##### swt_widget
Glimmer SWT proxies come with the instance method `#swt_widget`, which returns the actual SWT `Widget` object wrapped by the Glimmer widget proxy. It is useful in cases you'd like to do some custom SWT programming outside of Glimmer.
##### Shell widget proxy methods
Shell widget proxy has extra methods specific to SWT Shell:
- `#open`: Opens the shell, making it visible and active, and starting the SWT Event Loop (you may learn more about it here: https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/widgets/Display.html). If shell was already open, but hidden, it makes the shell visible.
- `#show`: Alias for `#open`
- `#hide`: Hides a shell setting "visible" property to false
- `#close`: Closes the shell
- `#center`: Centers the shell within monitor it is in
- `#start_event_loop`: (happens as part of `#open`) Starts SWT Event Loop (you may learn more about it here: https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/widgets/Display.html). This method is not needed except in rare circumstances where there is a need to start the SWT Event Loop before opening the shell.
- `#visible?`: Returns whether a shell is visible
- `#opened_before?`: Returns whether a shell has been opened at least once before (additionally implying the SWT Event Loop has been started already)
- `#visible=`: Setting to true opens/shows shell. Setting to false hides the shell.
- `#pack`: Packs contained widgets using SWT's `Shell#pack` method
- `#pack_same_size`: Packs contained widgets without changing shell's size when widget sizes change
##### Widget Content Block
Glimmer allows re-opening any widget and adding properties or extra content after it has been constructed already by using the `#content` method.
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
@shell = shell {
text "Application"
row_layout
@label1 = label {
text "Hello,"
}
}
@shell.content {
minimum_size 130, 130
label {
text "World!"
}
}
@label1.content {
foreground :red
}
@shell.open
```
##### Shell Icon
To set the shell icon, simply set the `image` property under the `shell` widget. This shows up in the operating system toolbar and app-switcher (e.g. CMD+TAB) (and application window top-left corner in Windows)
Example:
```ruby
shell {
# ...
image 'path/to/image.png'
# ...
}
```
###### Shell Icon Tip for Packaging on Windows
When setting shell icon for a [packaged](#packaging--distribution) app, which has a JAR file at its core, you can reference the `ico` file that ships with the app by going one level up (e.g. `'../AppName.ico'`)
#### Dialog
Dialog is a variation on Shell. It is basically a shell that is modal (blocks what's behind it) and belongs to another shell. It only has a close button.
Glimmer facilitates building dialogs by using the `dialog` keyword, which automatically adds the SWT.DIALOG_TRIM and SWT.APPLICATION_MODAL [widget styles](#widget-styles) needed for a dialog.
##### message_box
The Glimmer DSL `message_box` keyword is similar to `shell`, but renders a modal dialog with a title `text` property and main body `message` property. It may also be opened via the `#open` method.
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
include Glimmer
@shell = shell {
text 'Hello, Message Box!'
button {
text 'Please Click To Win a Surprise'
on_widget_selected {
message_box(@shell) {
text 'Surprise'
message "Congratulations!\n\nYou have won $1,000,000!"
}.open
}
}
}
@shell.open
```
![Hello Message Box Dialog](images/glimmer-hello-message-box-dialog.png)
It is also possible to use `message_box` even before instantiating the first `shell` ([Glimmer](https://rubygems.org/gems/glimmer) builds a throwaway `shell` parent automatically for it):
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
include Glimmer
message_box {
text 'Greeting'
message "Hello, World!"
}.open
```
#### Display
The SWT `Display` class is a singleton in Glimmer. It is used in SWT to represent your display device, allowing you to manage GUI globally
and access available monitors. Additionally, it is responsible for the SWT event loop, which runs on the first thread the Glimmer application starts on. In multi-threaded programming, `Display` provides the methods `async_exec` and `sync_exec` to enable enqueuing GUI changes asynchronously or synchronously from threads other than the main (first) thread since direct GUI changes are forbidden from other threads by design.
`Display` is automatically instantiated upon first instantiation of a `shell` widget.
Alternatively, for advanced use cases, a `Display` can be created explicitly with the Glimmer `display` keyword. When a `shell` is later declared, it
automatically uses the `display` created earlier without having to explicitly hook it.
```ruby
@display = display {
cursor_location 300, 300
on_swt_keydown {
# ...
}
# ...
}
@shell = shell { # uses display created above
}
```
The benefit of instantiating an SWT Display explicitly is to set [Properties](#widget-properties) or [Observers](#observer).
Although SWT Display is not technically a widget, it has similar APIs and DSL support.
#### Multi-Threading
[JRuby](https://www.jruby.org/) supports [truly parallel multi-threading](https://github.com/jruby/jruby/wiki/Concurrency-in-jruby) since it relies on the JVM (Java Virtual Machine). As such, it enables development of highly-interactive desktop applications that can do background work while the user is interacting with the GUI.
##### async_exec
`async_exec` is a Glimmer DSL keyword in addition to being a method on `display`. It accepts a block and when invoked, adds the block to the end of a queue of GUI events scheduled to run on the SWT event loop, executing asynchronously.
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```
@shell = shell {
text 'Glimmer'
@label = label {
text 'Hello, World!'
}
}
Thread.new {
[:red, :dark_green, :blue].cycle { |color|
async_exec {
@label.content {
foreground color if @shell.visible?
}
}
sleep(1)
}
}
@shell.open
```
##### sync_exec
`sync_exec` works just like `async_exec` except it executes the block synchronously at the earliest opportunity possible, waiting for the block to be finished.
#### Menus
Glimmer DSL provides support for SWT Menu and MenuItem widgets.
There are 2 main types of menus in SWT:
- Menu Bar (shows up on top)
- Pop Up Context Menu (shows up when right-clicking a widget)
Underneath both types, there can be a 3rd menu type called Drop Down.
Glimmer provides special support for Drop Down menus as it automatically instantiates associated Cascade menu items and wires together with proper parenting, swt styles, and calling setMenu.
The ampersand symbol indicates the keyboard shortcut key for the menu item (e.g. '&Help' can be triggered on Windows by hitting ALT+H)
Example of a Menu Bar (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
shell { |shell_proxy|
text 'Hello, Menu Bar!'
grid_layout
label(:center) {
font height: 16
text 'Check Out The File Menu and History Menu in The Menu Bar Above!'
}
menu_bar {
menu {
text '&File'
menu_item {
text 'E&xit'
}
menu_item(0) {
text '&New'
on_widget_selected {
message_box(shell_proxy) {
text 'New File'
message 'New File Contents'
}.open
}
}
menu(1) {
text '&Options'
menu_item(:radio) {
text 'Option 1'
}
menu_item(:separator)
menu_item(:check) {
text 'Option 3'
}
}
}
menu {
text '&History'
menu {
text '&Recent'
menu_item {
text 'File 1'
on_widget_selected {
message_box(shell_proxy) {
text 'File 1'
message 'File 1 Contents'
}.open
}
}
menu_item {
text 'File 2'
on_widget_selected {
message_box(shell_proxy) {
text 'File 2'
message 'File 2 Contents'
}.open
}
}
}
}
}
}.open
```
Example of a Pop Up Context Menu (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
shell { |shell_proxy|
text 'Hello, Pop Up Context Menu!'
grid_layout
label {
font height: 16
text 'Right-Click To Pop Up a Context Menu'
menu {
menu {
text '&History'
menu {
text '&Recent'
menu_item {
text 'File 1'
on_widget_selected {
message_box(shell_proxy) {
text 'File 1'
message 'File 1 Contents'
}.open
}
}
menu_item {
text 'File 2'
on_widget_selected {
message_box(shell_proxy) {
text 'File 2'
message 'File 2 Contents'
}.open
}
}
}
}
}
}
}.open
```
#### ScrolledComposite
Glimmer provides smart defaults for the `scrolled_composite` widget by:
- Automatically setting the nested widget as its content (meaning use can just like a plain old `composite` to add scrolling)
- Automatically setting the :h_scroll and :v_scroll SWT styles (can be set manually if only one of either :h_scroll or :v_scroll is desired )
- Automatically setting the expand horizontal and expand vertical SWT properties to `true`
### Widget Styles
SWT widgets receive `SWT` styles in their constructor as per this guide:
https://wiki.eclipse.org/SWT_Widget_Style_Bits
Glimmer DSL facilitates that by passing symbols representing `SWT` constants as widget method arguments (i.e. inside widget `()` parentheses according to [Glimmer Style Guide](#glimmer-style-guide). See example below) in lower case version (e.g. `SWT::MULTI` becomes `:multi`).
These styles customize widget look, feel, and behavior.
Example:
```ruby
# ...
list(:multi) { # SWT styles go inside ()
# ...
}
# ...
```
Passing `:multi` to `list` widget enables list element multi-selection.
```ruby
# ...
composite(:border) { # SWT styles go inside ()
# ...
}
# ...
```
Passing `:border` to `composite` widget ensures it has a border.
When you need to pass in **multiple SWT styles**, simply separate by commas.
Example:
```ruby
# ...
text(:center, :border) { # Multiple SWT styles separated by comma
# ...
}
# ...
```
Glimmer ships with SWT style **smart defaults** so you wouldn't have to set them yourself most of the time (albeit you can always override them):
- `text(:border)`
- `table(:border, :virtual, :full_selection)`
- `tree(:border, :virtual, :v_scroll, :h_scroll)`
- `spinner(:border)`
- `list(:border, :v_scroll)`
- `button(:push)`
You may check out all available `SWT` styles here:
https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html
#### Explicit SWT Style Bit
When building a widget-related SWT object manually (e.g. `GridData.new(...)`), you are expected to use `SWT::CONSTANT` directly or BIT-OR a few SWT constants together like `SWT::BORDER | SWT::V_SCROLL`.
Glimmer facilitates that with `swt` keyword by allowing you to pass multiple styles as an argument array of symbols instead of dealing with BIT-OR.
Example:
```ruby
style = swt(:border, :v_scroll)
```
#### Negative SWT Style Bits
In rare occasions, you might need to apply & with a negative (not) style bit to negate it from another style bit that includes it.
Glimmer facilitates that by declaring the negative style bit via postfixing a symbol with `!`.
Example:
```ruby
style = swt(:shell_trim, :max!) # creates a shell trim style without the maximize button (negated)
```
#### Extra SWT Styles
##### Non-resizable Window
SWT Shell widget by default is resizable. To make it non-resizable, one must pass a complicated style bit concoction like `swt(:shell_trim, :resize!, :max!)`.
Glimmer makes this easier by alternatively offering a `:no_resize` extra SWT style, added for convenience.
This makes declaring a non-resizable window as easy as:
```ruby
shell(:no_resize) {
# ...
}
```
### Widget Properties
Widget properties such as text value, enablement, visibility, and layout details are set within the widget block using methods matching SWT widget property names in lower snakecase. You may refer to SWT widget guide for details on available widget properties:
https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0
Code examples:
```ruby
# ...
label {
text "Hello, World!" # SWT properties go inside {} block
}
# ...
```
In the above example, the `label` widget `text` property was set to "Hello, World!".
```ruby
# ...
button {
enabled bind(@tic_tac_toe_board.box(row, column), :empty)
}
# ...
```
In the above example, the `text` widget `enabled` property was data-bound to `#empty` method on `@tic_tac_toe_board.box(row, column)` (learn more about data-binding below)
#### Color
Colors make up a subset of widget properties. SWT accepts color objects created with RGB (Red Green Blue) or RGBA (Red Green Blue Alpha). Glimmer supports constructing color objects using the `rgb` and `rgba` DSL keywords.
Example:
```ruby
# ...
label {
background rgb(144, 240, 244)
foreground rgba(38, 92, 232, 255)
}
# ...
```
SWT also supports standard colors available as constants under the `SWT` namespace with the `COLOR_` prefix (e.g. `SWT::COLOR_BLUE`)
Glimmer supports constructing colors for these constants as lowercase Ruby symbols (with or without `color_` prefix) passed to `color` DSL keyword
Example:
```ruby
# ...
label {
background color(:black)
foreground color(:yellow)
}
label {
background color(:color_white)
foreground color(:color_red)
}
# ...
```
You may check out all available standard colors in `SWT` over here (having `COLOR_` prefix):
https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html
##### `#swt_color`
Glimmer color objects come with an instance method `#swt_color` that returns the actual SWT `Color` object wrapped by the Glimmer color object. It is useful in cases you'd like to do some custom SWT programming outside of Glimmer.
Example:
```ruby
color(:black).swt_color # returns SWT Color object
```
#### Font
Fonts are represented in Glimmer as a hash of name, height, and style keys.
The style can be one (or more) of 3 values: `:normal`, `:bold`, and `:italic`
Example:
```ruby
# ...
label {
font name: 'Arial', height: 36, style: :normal
}
# ...
```
Keys are optional, so some of them may be left off.
When passing multiple styles, they are included in an array.
Example:
```ruby
# ...
label {
font style: [:bold, :italic]
}
# ...
```
You may simply use the standalone `font` keyword without nesting in a parent if there is a need to build a Font object to use in manual SWT programming outside of widget font property setting.
Example:
```ruby
@font = font(name: 'Arial', height: 36, style: :normal)
```
### Image
The `image` keyword creates an instance of [org.eclipse.swt.graphics.Image](https://help.eclipse.org/2020-09/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/graphics/Image.html).
It is a graphics `Image` object (not a widget), but is used used in setting the `image` property on `label` and `background_image` on `composite` (and subclasses)
Glimmer recently included **EXPERIMENTAL** gif animation support for the `background_image` property on `composite' since SWT does not support animation by default. On Windows, it only works inside composites nested under standard shells, not ones that have the SWT styles :on_top or :no_trim
Learn more about images in general at this SWT Image guide: https://www.eclipse.org/articles/Article-SWT-images/graphics-resources.html
#### Image Options
Options may be passed in a hash at the end of `image` arguments:
- `width`: width of image
- `height`: height of image
If only the width or height alone are specified, the other is calculated while maintaining the image aspect ratio.
Example:
```
label {
image 'someimage.png', width: 400, height: 300
}
```
### Cursor
SWT widget `cursor` property represents the mouse cursor you see on the screen when you hover over that widget.
The `Display` class provides a way to obtain standard system cursors matching of the SWT style constants starting with prefix `CURSOR_` (e.g. `SWT::CURSOR_HELP` shows a question mark mouse cursor)
Glimmer provides an easier way to obtain and set `cursor` property on a widget by simply mentioning the SWT style constant as an abbreviated symbol excluding the "CURSOR_" suffix.
Example:
```ruby
shell {
minimum_size 128, 128
cursor :appstarting
}
```
This sets the shell `cursor` to that of `SWT::CURSOR_APPSTARTING`
### Layouts
Glimmer lays widgets out visually using SWT layouts, which can only be set on composite widget and subclasses.
The most common SWT layouts are:
- `FillLayout`: lays widgets out in equal proportion horizontally or vertically with spacing/margin options. This is the ***default*** layout for ***shell*** (with `:horizontal` option) in Glimmer.
- `RowLayout`: lays widgets out horizontally or vertically in varying proportions with advanced spacing/margin/justify options
- `GridLayout`: lays widgets out in a grid with advanced spacing/margin/alignment/indentation options. This is the **default** layout for **composite** in Glimmer. It is important to master.
In Glimmer DSL, just like widgets, layouts can be specified with lowercase underscored names followed by a block containing properties, also lowercase underscored names (e.g. `RowLayout` is `row_layout`).
Example:
```ruby
# ...
composite {
row_layout {
wrap true
pack false
justify true
type :vertical
margin_left 1
margin_top 2
margin_right 3
margin_bottom 4
spacing 5
}
# ... widgets follow
}
# ...
```
If you data-bind any layout properties, when they change, the shell containing their widget re-packs its children (calls `#pack` method automatically) to ensure proper relayout of all widgets.
Alternatively, a layout may be constructed by following the SWT API for the layout object. For example, a `RowLayout` can be constructed by passing it an SWT style constant (Glimmer automatically accepts symbols (e.g. `:horizontal`) for SWT style arguments like `SWT::HORIZONTAL`.)
```ruby
# ...
composite {
row_layout :horizontal
# ... widgets follow
}
# ...
```
Here is a more sophisticated example taken from [hello_computed.rb](samples/hello/hello_computed.rb) sample:
![Hello Computed](images/glimmer-hello-computed.png)
```ruby
shell {
text 'Hello, Computed!'
composite {
grid_layout {
num_columns 2
make_columns_equal_width true
horizontal_spacing 20
vertical_spacing 10
}
label {text 'First &Name: '}
text {
text bind(@contact, :first_name)
layout_data {
horizontal_alignment :fill
grab_excess_horizontal_space true
}
}
label {text '&Last Name: '}
text {
text bind(@contact, :last_name)
layout_data {
horizontal_alignment :fill
grab_excess_horizontal_space true
}
}
label {text '&Year of Birth: '}
text {
text bind(@contact, :year_of_birth)
layout_data {
horizontal_alignment :fill
grab_excess_horizontal_space true
}
}
label {text 'Name: '}
label {
text bind(@contact, :name, computed_by: [:first_name, :last_name])
layout_data {
horizontal_alignment :fill
grab_excess_horizontal_space true
}
}
label {text 'Age: '}
label {
text bind(@contact, :age, on_write: :to_i, computed_by: [:year_of_birth])
layout_data {
horizontal_alignment :fill
grab_excess_horizontal_space true
}
}
}
}.open
```
Check out the samples directory for more advanced examples of layouts in Glimmer.
**Defaults**:
Glimmer composites always come with `grid_layout` by default, but you can still specify explicitly if you'd like to set specific properties on it.
Glimmer shell always comes with `fill_layout` having `:horizontal` type.
This is a great guide for learning more about SWT layouts:
https://www.eclipse.org/articles/Article-Understanding-Layouts/Understanding-Layouts.htm
Also, for a reference, check the SWT API:
https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/index.html
### Layout Data
Layouts organize widgets following common rules for all widgets directly under a composite. But, what if a specific widget needs its own rules. That's where layout data comes into play.
By convention, SWT layouts expect widgets to set layout data with a class matching their class name with the word "Data" replacing "Layout":
- `GridLayout` on a composite demands `GridData` on contained widgets
- `RowLayout` on a composite demands `RowData` on contained widgets
Not all layouts support layout data to further customize widget layouts. For example, `FillLayout` supports no layout data.
Unlike widgets and layouts in Glimmer DSL, layout data is simply specified with `layout_data` keyword nested inside a widget block body, and followed by arguments and/or a block of its own properties (lowercase underscored names).
Glimmer automatically deduces layout data class name by convention as per rule above, with the assumption that the layout data class lives under the same exact Java package as the layout (one can set custom layout data that breaks convention if needed in rare cases. See code below for an example)
Glimmer also automatically accepts symbols (e.g. `:fill`) for SWT style arguments like `SWT::FILL`.
Examples:
```ruby
# ...
composite {
row_layout :horizontal
label {
layout_data { # followed by properties
width 50
height 30
}
}
# ... more widgets follow
}
# ...
```
```ruby
# ...
composite {
grid_layout 3, false # grid layout with 3 columns not of equal width
label {
# layout data followed by arguments passed to SWT GridData constructor
layout_data :fill, :end, true, false
}
}
# ...
```
```ruby
# ...
composite {
grid_layout 3, false # grid layout with 3 columns not of equal width
label {
# layout data set explicitly via an object (helps in rare cases that break convention)
layout_data GridData.new(swt(:fill), swt(:end), true, false)
}
}
# ...
```
If you data-bind any layout data properties, when they change, the shell containing their widget re-packs its children (calls `#pack` method automatically) to ensure proper relayout of all widgets.
**NOTE**: Layout data must never be reused between widgets. Always specify or clone again for every widget.
This is a great guide for learning more about SWT layouts:
https://www.eclipse.org/articles/Article-Understanding-Layouts/Understanding-Layouts.htm
Also, for a reference, check the SWT API:
https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/index.html
### Data-Binding
Data-binding is done with `bind` command following widget property to bind and taking model and bindable attribute as arguments.
#### General Examples
`text bind(contact, :first_name)`
This example binds the text property of a widget like `label` to the first name of a contact model.
`text bind(contact, 'address.street')`
This example binds the text property of a widget like `label` to the nested street of
the address of a contact. This is called nested property data binding.
`text bind(contact, 'address.street', on_read: :upcase, on_write: :downcase)`
This example adds on the one above it by specifying converters on read and write of the model property, like in the case of a `text` widget. The text widget will then displays the street upper case and the model will store it lower case. When specifying converters, read and write operations must be symmetric (to avoid an infinite update loop between the widget and the model since the widget checks first if value changed before updating)
`text bind(contact, 'address.street', on_read: lambda { |s| s[0..10] })`
This example also specifies a converter on read of the model property, but via a lambda, which truncates the street to 10 characters only. Note that the read and write operations are assymetric. This is fine in the case of formatting data for a read-only widget like `label`
`text bind(contact, 'address.street') { |s| s[0..10] }`
This is a block shortcut version of the syntax above it. It facilitates formatting model data for read-only widgets since it's a very common view concern. It also saves the developer from having to create a separate formatter/presenter for the model when the view can be an active view that handles common simple formatting operations directly.
`text bind(contact, 'address.street', read_only: true)
This is read-ohly data-binding. It doesn't update contact.address.street when widget text property is changed.
`text bind(contact, 'addresses[1].street')`
This example binds the text property of a widget like `label` to the nested indexed address street of a contact. This is called nested indexed property data binding.
`text bind(contact, :age, computed_by: :date_of_birth)`
This example demonstrates computed value data binding whereby the value of `age` depends on changes to `date_of_birth`.
`text bind(contact, :name, computed_by: [:first_name, :last_name])`
This example demonstrates computed value data binding whereby the value of `name` depends on changes to both `first_name` and `last_name`.
`text bind(contact, 'profiles[0].name', computed_by: ['profiles[0].first_name', 'profiles[0].last_name'])`
This example demonstrates nested indexed computed value data binding whereby the value of `profiles[0].name` depends on changes to both nested `profiles[0].first_name` and `profiles[0].last_name`.
Example from [samples/hello/hello_combo.rb](samples/hello_combo.rb) sample (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
#### Combo
The `combo` widget provides a dropdown of options. By default, it also allows typing in a new option. To disable that behavior, you may use with the `:read_only` SWT style.
When data-binding a `combo` widget, Glimmer can automatically deduce available options from data-bound model by convention: `{attribute_name}_options` method.
![Hello Combo](images/glimmer-hello-combo.png)
![Hello Combo](images/glimmer-hello-combo-expanded.png)
```ruby
class Person
attr_accessor :country, :country_options
def initialize
self.country_options=["", "Canada", "US", "Mexico"]
self.country = "Canada"
end
def reset_country
self.country = "Canada"
end
end
class HelloCombo
include Glimmer
def launch
person = Person.new
shell {
composite {
combo(:read_only) {
selection bind(person, :country)
}
button {
text "Reset"
on_widget_selected do
person.reset_country
end
}
}
}.open
end
end
HelloCombo.new.launch
```
`combo` widget is data-bound to the country of a person. Note that it expects the `person` object to have the `:country` attribute and `:country_options` attribute containing all available countries (aka options). Glimmer reads these attributes by convention.
#### List
Example from [samples/hello/hello_list_single_selection.rb](samples/hello_list_single_selection.rb) sample:
![Hello List Single Selection](images/glimmer-hello-list-single-selection.png)
```ruby
shell {
composite {
list {
selection bind(person, :country)
}
button {
text "Reset"
on_widget_selected do
person.reset_country
end
}
}
}.open
```
`list` widget is also data-bound to the country of a person similarly to the combo widget. Not much difference here (the rest of the code not shown is the same).
Nonetheless, in the next example, a multi-selection list is declared instead allowing data-binding of multiple selection values to the bindable attribute on the model.
Example from [samples/hello/hello_list_multi_selection.rb](samples/hello_list_multi_selection.rb) sample (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
![Hello List Multi Selection](images/glimmer-hello-list-multi-selection.png)
```ruby
class Person
attr_accessor :provinces, :provinces_options
def initialize
self.provinces_options=[
"",
"Quebec",
"Ontario",
"Manitoba",
"Saskatchewan",
"Alberta",
"British Columbia",
"Nova Skotia",
"Newfoundland"
]
self.provinces = ["Quebec", "Manitoba", "Alberta"]
end
def reset_provinces
self.provinces = ["Quebec", "Manitoba", "Alberta"]
end
end
class HelloListMultiSelection
include Glimmer
def launch
person = Person.new
shell {
composite {
list(:multi) {
selection bind(person, :provinces)
}
button {
text "Reset"
on_widget_selected do
person.reset_provinces
end
}
}
}.open
end
end
HelloListMultiSelection.new.launch
```
The Glimmer code is not much different from above except for passing the `:multi` style to the `list` widget. However, the model code behind the scenes is quite different as it is a `provinces` array bindable to the selection of multiple values on a `list` widget. `provinces_options` contains all available province values just as expected by a single selection `list` and `combo`.
Note that in all the data-binding examples above, there was also an observer attached to the `button` widget to trigger an action on the model, which in turn triggers a data-binding update on the `list` or `combo`. Observers will be discussed in more details in the [next section](#observer).
You may learn more about Glimmer's data-binding syntax by reading the code under the [samples](samples) directory.
#### Table
The SWT Tree widget renders a multi-column data table, such as a contact listing or a sales report.
To data-bind a Table, you need the main model, the collection property, and the text display attribute for each table column.
This involves using the `bind` keyword mentioned above in addition to a special `column_properties` keyword that takes the table column text attribute methods.
It assumes you have defined the table columns via `table_column` widget.
Example:
```ruby
shell {
@table = table {
table_column {
text "Name"
width 120
}
table_column {
text "Age"
width 120
}
table_column {
text "Adult"
width 120
}
items bind(group, :people), column_properties(:name, :age, :adult)
selection bind(group, :selected_person)
on_mouse_up { |event|
@table.edit_table_item(event.table_item, event.column_index)
}
}
}
```
The code above includes two data-bindings:
- Table `items`, which first bind to the model collection property (group.people), and then maps each column property (name, age, adult) for displaying each table item column.
- Table `selection`, which binds the single table item selected by the user to the attribute denoted by the `bind` keyword (or binds multiple table items selected for a table with `:multi` SWT style)
- The `on_mouse_up` event handler invokes `@table.edit_table_item(event.table_item, event.column_index)` to start edit mode on the clicked table item cell, and then saves or cancel depending on whether the user hits ENTER or ESC once done editing (or focus-out after either making a change or not making any changes.)
Additionally, Table `items` data-binding automatically stores each node model unto the SWT TableItem object via `setData` method. This enables things like searchability.
The table widget in Glimmer is represented by a subclass of `WidgetProxy` called `TableProxy`.
TableProxy includes a `search` method that takes a block to look for a table item.
Example:
```ruby
found_array = @table.search { |table_item| table_item.getData == company.owner }
```
This finds a person. The array is a Java array. This enables easy passing of it to SWT `Table#setSelection` method, which expects a Java array of `TableItem` objects.
To edit a table, you must invoke `TableProxy#edit_selected_table_item(column_index, before_write: nil, after_write: nil, after_cancel: nil)` or `TableProxy#edit_table_item(table_item, column_index, before_write: nil, after_write: nil, after_cancel: nil)`.
This automatically leverages the SWT TableEditor custom class behind the scenes, displaying a text widget to the user to change the selected or
passed table item text into something else.
It automatically persists the change to `items` data-bound model on ENTER/FOCUS-OUT or cancels on ESC/NO-CHANGE.
##### Table Selection
Table Selection data-binding is simply done via the `selection` property.
```ruby
selection bind(group, :selected_person)
```
If it's a multi-selection table (`table(:multi)`), then the data-bound model property oughta be a collection.
```ruby
selection bind(group, :selected_people)
```
##### Table Editing
Glimmer provides a custom SWT style for table editing called `:editable` to obviate the need for an `on_mouse_up` listener.
For example, the code above could be simplified as:
```ruby
shell {
@table = table(:editable) {
table_column {
text "Name"
width 120
}
table_column {
text "Age"
width 120
}
table_column {
text "Adult"
width 120
}
items bind(group, :people), column_properties(:name, :age, :adult)
selection bind(group, :selected_person)
}
}
```
Additionally, Glimmer supports the idea of custom editors or no editor per column.
Example:
```ruby
shell {
@table = table(:editable) {
table_column {
text "Name"
width 120
}
table_column {
text "Age"
width 120
editor :spinner
}
table_column {
text "Adult"
width 120
editor :checkbox
}
items bind(group, :people), column_properties(:name, :age, :adult)
selection bind(group, :selected_person)
}
}
```
The example above uses a `spinner` widget editor for the age column since it's an `Integer` and
a `checkbox` widget (`button(:check)`) editor for the adult column since it's a `Boolean`
Here are all the supported types of table editors:
- `text`: expects a `String` property
- `combo`: expects a `String` property accompanied by a matching `property_options` property by convention to provide items to present in the `combo`
- `checkbox`: expects a `Boolean` property
- `radio`: expects a `Boolean` property
- `spinner`: expects an `Integer` property
- `date`: expects a `DateTime` property
- `date_drop_down`: expects a `DateTime` property
- `time`: expects a `DateTime` property
An editor may also take additional arguments (SWT styles such as :long for the date field) that are passed to the editor widget, as well as hash options to
customize the property being used for editing (e.g. property: :raw_name for a :formatted_name field) in case it differs from the property used to display
the data in the table.
Example:
```ruby
shell {
@table = table(:editable) {
table_column {
text "Date of Birth"
width 120
editor :date_drop_down, property: :date_time
}
table_column {
text "Industry"
width 120
# assume there is a `Person#industry_options` property method on the model to provide items to the `combo`
editor :combo, :read_only # passes :ready_only SWT style to `combo` widget
}
items bind(group, :people), column_properties(:formatted_date, :industry)
selection bind(group, :selected_person)
}
}
```
Check out [Hello, Table!](#hello-table) for an actual example including table editors.
[Are We There Yet?](#are-we-there-yet) is an actual production Glimmer application that takes full advantage of table capabilities.
##### Table Sorting
Glimmer automatically adds sorting support to the SWT `Table` widget.
Check out the [Contact Manager](#contact-manager) sample for an example.
You may click on any column and it will sort by ascending order first and descending if you click again.
Glimmer automatic table sorting supports `String`, `Integer`, and `Float` columns out of the box as well as any column data that is comparable.
In cases where data is nil, depending on the data-type, it is automatically converted to `Float` with `to_f`, `Integer` with `to_i`, or `String` with `to_s`.
Should you have a special data type that could not be compared automatically, Glimmer offers the following 3 alternatives for custom sorting:
- `sort_property`: this may be set to an alternative property to the one data-bound to the table column. For example, a table column called 'adult', which returns `true` or `false` may be sorted with `sort_property :dob` instead. This also support multi-property (aka multi-column) sorting (e.g. `sort_property :dob, :name`).
- `sort_by(&block)`: this works just like Ruby `Enumerable` `sort_by`. The block receives the table column data as argument.
- `sort(&comparator)`: this works just like Ruby `Enumerable` `sort`. The comparator block receives two objects from the table column data.
These alternatives could be used inside `table_column` for column-clicked sorting or in the `table` body directly to set the initial default sort.
You may also set `additional_sort_properties` on the parent `table` widget to have secondary sorting applied. For example, if you set `additional_sort_properties :name, :project_name`, then whenever you sort by `:name`, it additionally sorts by `:project_name` afterwards, and vice versa. This only works for columns that either have no custom sort set or have a `sort_property` with one property only (but no sort or sort_by block)
Example:
```ruby
# ...
table {
table_column {
text 'Task'
width 120
}
table_column {
text 'Project'
width 120
}
table_column {
text 'Duration (hours)'
width 120
sort_property :duration_in_hours
}
table_column {
text 'Priority'
width 120
sort_by { |value| ['High', 'Medium', 'Low'].index(value) }
}
table_column {
text 'Start Date'
width 120
sort { |d1, d2| d1.to_date <=> d2.to_date }
}
additional_sort_properties :project_name, :duration_in_hours, :name
items bind(Task, :list), column_properties(:name, :project_name, :duration, :priority, :start_date)
# ...
}
# ...
```
Here is an explanation of the example above:
- Task and Project table columns are data-bound to the `:name` and `:project_name` properties and sorted through them automatically
- Task Duration table column is data-bound to the `:duration` property, but sorted via the `:duration_in_hours` property instead
- Task Priority table column has a custom sort_by block
- Task Start Date table column has a custom sort comparator block
- Additional (secondary) sort properties are applied when sorting by Task, Project, or Duration in the order specified
#### Tree
The SWT Tree widget visualizes a tree data-structure, such as an employment or composition hierarchy.
To data-bind a Tree, you need the root model, the children querying method, and the text display attribute on each child.
This involves using the `bind` keyword mentioned above in addition to a special `tree_properties` keyword that takes the children and text attribute methods.
Example:
```ruby
shell {
@tree = tree {
items bind(company, :owner), tree_properties(children: :coworkers, text: :name)
selection bind(company, :selected_coworker)
}
}
```
The code above includes two data-bindings:
- Tree `items`, which first bind to the root node (company.owner), and then dig down via `coworkers` `children` method, using the `name` `text` attribute for displaying each tree item.
- Tree `selection`, which binds the single tree item selected by the user to the attribute denoted by the `bind` keyword
Additionally, Tree `items` data-binding automatically stores each node model unto the SWT TreeItem object via `setData` method. This enables things like searchability.
The tree widget in Glimmer is represented by a subclass of `WidgetProxy` called `TreeProxy`.
TreeProxy includes a `depth_first_search` method that takes a block to look for a tree item.
Example:
```ruby
found_array = @tree.depth_first_search { |tree_item| tree_item.getData == company.owner }
```
This finds the root node. The array is a Java array. This enables easy passing of it to SWT `Tree#setSelection` method, which expects a Java array of `TreeItem` objects.
To edit a tree, you must invoke `TreeProxy#edit_selected_tree_item` or `TreeProxy#edit_tree_item`. This automatically leverages the SWT TreeEditor custom class behind the scenes, displaying
a text widget to the user to change the selected or passed tree item text into something else. It automatically persists the change to `items` data-bound model on ENTER/FOCUS-OUT or cancels on ESC/NO-CHANGE.
#### DateTime
`date_time` represents the SWT DateTime widget.
Glimmer offers the following alias keywords for it for convenience:
- `date`: `date_time(:date)`
- `date_drop_down`: `date_time(:date, :drop_down)`
- `time`: `date_time(:time)`
- `calendar`: `date_time(:calendar)`
You can data-bind any of these properties:
- `date_time bind(model, :property)`: produces a Ruby DateTime object
- `date bind(model, :property)`: produces a Ruby Date object
- `time bind(model, :property)`: produces a Ruby Time object
- `year bind(model, :property)`: produces an integer
- `month bind(model, :property)`: produces an integer
- `day bind(model, :property)`: produces an integer
- `hours bind(model, :property)`: produces an integer
- `minutes bind(model, :property)`: produces an integer
- `seconds bind(model, :property)`: produces an integer
Learn more at the [Hello, Date Time!](#hello-date-time) sample.
If you need a better widget with the ability to customize the date format pattern, check out the [Nebula CDateTime Glimmer Custom Widget](https://github.com/AndyObtiva/glimmer-cw-cdatetime-nebula)
### Observer
Glimmer comes with `Observer` module, which is used internally for data-binding, but can also be used externally for custom use of the Observer Pattern. It is hidden when observing widgets, and used explicitly when observing models.
#### Observing Widgets
Glimmer supports observing widgets with two main types of events:
1. `on_{swt-listener-method-name}`: where {swt-listener-method-name} is replaced with the lowercase underscored event method name on an SWT listener class (e.g. `on_verify_text` for `org.eclipse.swt.events.VerifyListener#verifyText`).
2. `on_swt_{swt-event-constant}`: where {swt-event-constant} is replaced with an [`org.eclipse.swt.SWT`](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html) event constant (e.g. `on_swt_show` for `SWT.Show` to observe when widget becomes visible)
Additionally, there are two more types of events:
- SWT `display` supports global listeners called filters that run on any widget. They are hooked via `on_swt_{swt-event-constant}`
- SWT `display` supports Mac application menu item observers (`on_about` and `on_preferences`), which you can read about under [Miscellaneous](#miscellaneous).
Number 1 is more commonly used in SWT applications, so make it your starting point. Number 2 covers events not found in number 1, so look into it if you don't find an SWT listener you need in number 1.
**Regarding number 1**, to figure out what the available events for an SWT widget are, check out all of its `add***Listener` API methods, and then open the listener class argument to check its "event methods".
For example, if you look at the `Button` SWT API:
https://help.eclipse.org/2019-12/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fswt%2Fbrowser%2FBrowser.html
It has `addSelectionListener`. Additionally, under its `Control` super class, it has `addControlListener`, `addDragDetectListener`, `addFocusListener`, `addGestureListener`, `addHelpListener`, `addKeyListener`, `addMenuDetectListener`, `addMouseListener`, `addMouseMoveListener`, `addMouseTrackListener`, `addMouseWheelListener`, `addPaintListener`, `addTouchListener`, and `addTraverseListener`
Suppose, we select `addSelectionListener`, which is responsible for what happens when a user selects a button (clicks it). Then, open its argument `SelectionListener` SWT API, and you find the event (instance) methods: `widgetDefaultSelected` and `widgetSelected`. Let's select the second one, which is what gets invoked when a button is clicked.
Now, Glimmer simplifies the process of hooking into that listener (observer) by neither requiring you to call the `addSelectionListener` method nor requiring you to implement/extend the `SelectionListener` API.
Instead, simply add a `on_widget_selected` followed by a Ruby block containing the logic to perform. Glimmer figures out the rest.
Let's revisit the Tic Tac Toe example shown near the beginning of the page:
```ruby
shell {
text "Tic-Tac-Toe"
minimum_size 150, 178
composite {
grid_layout 3, true
(1..3).each { |row|
(1..3).each { |column|
button {
layout_data :fill, :fill, true, true
text bind(@tic_tac_toe_board[row, column], :sign)
enabled bind(@tic_tac_toe_board[row, column], :empty)
on_widget_selected {
@tic_tac_toe_board.mark(row, column)
}
}
}
}
}
}
```
Note that every Tic Tac Toe grid cell has its `text` and `enabled` properties data-bound to the `sign` and `empty` attributes on the `TicTacToe::Board` model respectively.
Next however, each of these Tic Tac Toe grid cells, which are clickable buttons, have an `on_widget_selected` observer, which once triggered, marks the cell on the `TicTacToe::Board` to make a move.
**Regarding number 2**, you can figure out all available events by looking at the [`org.eclipse.swt.SWT`](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html) API:
https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
`SWT.Show` - hooks a listener for showing a widget (using `on_swt_show` in Glimmer)
`SWT.Hide` - hooks a listener for hiding a widget (using `on_swt_hide` in Glimmer)
```ruby
shell {
@button1 = button {
text "Show 2nd Button"
visible true
on_swt_show {
@button2.swt_widget.setVisible(false)
}
on_widget_selected {
@button2.swt_widget.setVisible(true)
}
}
@button2 = button {
text "Show 1st Button"
visible false
on_swt_show {
@button1.swt_widget.setVisible(false)
}
on_widget_selected {
@button1.swt_widget.setVisible(true)
}
}
}.open
```
**Gotcha:** SWT.Resize event needs to be hooked using **`on_swt_Resize`** because [`org.eclipse.swt.SWT`](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html) has 2 constants for resize: `RESIZE` and `Resize`, so it cannot infer the right one automatically from the underscored version `on_swt_resize`
##### Alternative Syntax
Instead of declaring a widget observer using `on_***` syntax inside a widget content block, you may also do so after the widget declaration by invoking directly on the widget object.
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```
@shell = shell {
label {
text "Hello, World!"
}
}
@shell.on_shell_iconified {
@shell.close
}
@shell.open
```
The shell declared above has been modified so that the minimize button works just like the close button. Once you minimize the shell (iconify it), it closes.
The alternative syntax can be helpful if you prefer to separate Glimmer observer declarations from Glimmer GUI declarations, or would like to add observers dynamically based on some logic later on.
#### Observing Models
Glimmer DSL includes an `observe` keyword used to register an observer by passing in the observable and the property(ies) to observe, and then specifying in a block what happens on notification.
```ruby
class TicTacToe
include Glimmer
def initialize
# ...
observe(@tic_tac_toe_board, :game_status) { |game_status|
display_win_message if game_status == Board::WIN
display_draw_message if game_status == Board::DRAW
}
end
# ...
end
```
Observers can be a good mechanism for displaying dialog messages in Glimmer (using SWT's [`MessageBox`](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/widgets/MessageBox.html) class).
Look at [`samples/elaborate/tictactoe/tic_tac_toe.rb`](samples/tictactoe/tic_tac_toe.rb) for more details starting with the code included below.
```ruby
class TicTacToe
include Glimmer
include Observer
def initialize
# ...
observe(@tic_tac_toe_board, :game_status) { |game_status|
display_win_message if game_status == Board::WIN
display_draw_message if game_status == Board::DRAW
}
end
def display_win_message
display_game_over_message("Player #{@tic_tac_toe_board.winning_sign} has won!")
end
def display_draw_message
display_game_over_message("Draw!")
end
def display_game_over_message(message)
message_box(@shell) {
text 'Game Over'
message message_text
}.open
@tic_tac_toe_board.reset
end
# ...
end
```
### Custom Widgets
Custom widgets are brand new Glimmer DSL keywords that represent aggregates of existing widgets (e.g. `address_form`), customized existing widgets (e.g. `greeting_label`), or brand new widgets (e.g. `oscilloscope`)
You can find out about [published Glimmer Custom Widgets](https://github.com/AndyObtiva/glimmer-dsl-swt#gem-listing) by running the `glimmer list:gems:customwidget` command
Glimmer supports three ways of creating custom widgets with minimal code:
1. Method-based Custom Widgets (for single-view-internal reuse): Extract a method containing Glimmer DSL widget syntax. Useful for quickly eliminating redundant code within a single view.
2. Class-based Custom Widgets (for multiple-view-external reuse): Create a class that includes the `Glimmer::UI::CustomWidget` module and Glimmer DSL widget syntax in a `body {}` block. This will automatically extend Glimmer's DSL syntax with an underscored lowercase keyword matching the class name by convention. Useful in making a custom widget available in many views.
Approach #1 is a casual Ruby-based approach. Approach #2 is the official Glimmer approach. Typically, when referring to Custom Widgets, we are talking about Class-based Custom Widgets.
A developer might start with approach #1 to eliminate duplication in a view and later upgrade it to approach #2 when needing to export a custom widget to make it available in many views.
Class-based Custom Widgets offer a number of benefits over method-based custom widgets, such as built-in support for passing SWT style, nested block of extra widgets and properties, and `before_body`/`after_body` hooks.
#### Simple Example
##### Method-Based Custom Widget Example
(you may copy/paste in [`girb`](#girb-glimmer-irb-command))
Definition and usage in the same file:
```ruby
def red_label(label_text)
label {
text label_text
background :red
}
end
shell {
red_label('Red Label')
}.open
```
##### Class-Based Custom Widget Example
Simply create a new class that includes `Glimmer::UI::CustomWidget` and put Glimmer DSL code in its `#body` block (its return value is stored in `#body_root` attribute). Glimmer will then automatically recognize this class by convention when it encounters a keyword matching the class name converted to underscored lowercase (and namespace double-colons `::` replaced with double-underscores `__`)
(you may copy/paste in [`girb`](#girb-glimmer-irb-command))
Definition:
```ruby
class RedLabel
include Glimmer::UI::CustomWidget
body {
label(swt_style) {
background :red
}
}
end
```
Usage:
```ruby
shell {
red_label(:center) {
text 'Red Label'
foreground :green
}
}.open
```
As you can see, `RedLabel` became the Glimmer DSL keyword `red_label` and worked just like a standard label by taking in SWT style and nested properties. As such, it is a first-class citizen of the Glimmer GUI DSL.
#### Custom Widget Lifecycle Hooks
You may execute code before or after evaluating the body with these lifecycle hooks:
- `before_body`: takes a block that executes in the custom widget instance scope before calling `body`. Useful for initializing variables to later use in `body`
- `after_body`: takes a block that executes in the custom widget instance scope after calling `body`. Useful for setting up observers on widgets built in `body` (set in instance variables) and linking to other shells.
#### Lifecycle Hooks Example
(you may copy/paste in [`girb`](#girb-glimmer-irb-command))
Definition:
```ruby
module Red
class Composite
include Glimmer::UI::CustomWidget
before_body {
@color = :red
}
body {
composite(swt_style) {
background @color
}
}
end
end
```
Usage:
```ruby
shell {
red__composite {
label {
foreground :white
text 'This is showing inside a Red Composite'
}
}
}.open
```
Notice how `Red::Composite` became `red__composite` with double-underscore, which is how Glimmer Custom Widgets signify namespaces by convention. Additionally, the `before_body` lifecycle hook was utilized to set a `@color` variable and use inside the `body`.
Keep in mind that namespaces are not needed to be specified if the Custom Widget class has a unique name, not clashing with a basic SWT widget or another custom widget name.
#### Custom Widget API
Custom Widgets have the following attributes available to call from inside the `#body` method:
- `#parent`: Glimmer object parenting custom widget
- `#swt_style`: SWT style integer. Can be useful if you want to allow consumers to customize a widget inside the custom widget body
- `#options`: a hash of options passed in parentheses when declaring a custom widget (useful for passing in model data) (e.g. `calendar(events: events)`). Custom widget class can declare option names (array) with `::options` class method as shown below, which generates attribute accessors for every option (not to be confused with `#options` instance method for retrieving options hash containing names & values)
- `#content`: nested block underneath custom widget. It will be automatically called at the end of processing the custom widget body. Alternatively, the custom widget body may call `content.call` at the place where the content is needed to show up as shown in the following example.
- `#body_root`: top-most (root) widget returned from `#body` method.
- `#swt_widget`: actual SWT widget for `body_root`
Additionally, custom widgets can call the following class methods:
- `::options(*option_names)`: declares a list of options by taking an option name array (symbols/strings). This generates option attribute accessors (e.g. `options :orientation, :bg_color` generates `#orientation`, `#orientation=(v)`, `#bg_color`, and `#bg_color=(v)` attribute accessors)
- `::option(option_name, default: nil)`: declares a single option taking option name and default value as arguments (also generates attribute accessors just like `::options`)
#### Content/Options Example
(you may copy/paste in [`girb`](#girb-glimmer-irb-command))
Definition:
```ruby
class Sandwich
include Glimmer::UI::CustomWidget
options :orientation, :bg_color
option :fg_color, default: :black
body {
composite(swt_style) { # gets custom widget style
fill_layout orientation # using orientation option
background bg_color # using container_background option
label {
text 'SANDWICH TOP'
}
content.call # this is where content block is called
label {
text 'SANDWICH BOTTOM'
}
}
}
end
```
Usage:
```ruby
shell {
sandwich(:no_focus, orientation: :vertical, bg_color: :red) {
label {
background :green
text 'SANDWICH CONTENT'
}
}
}.open
```
Notice how `:no_focus` was the `swt_style` value, followed by the `options` hash `{orientation: :horizontal, bg_color: :white}`, and finally the `content` block containing the label with `'SANDWICH CONTENT'`
#### Gotcha
Beware of defining a custom attribute that is a common SWT widget property name.
For example, if you define `text=` and `text` methods to accept a custom text and then later you write this body:
```ruby
# ...
def text
# ...
end
def text=(value)
# ...
end
body {
composite {
label {
text "Hello"
}
label {
text "World"
}
}
}
# ...
```
The `text` method invoked in the custom widget body will call the one you defined above it. To avoid this gotcha, simply name the text property above something else, like `custom_text`.
#### Final Notes
This [Eclipse guide](https://www.eclipse.org/articles/Article-Writing%20Your%20Own%20Widget/Writing%20Your%20Own%20Widget.htm) for how to write custom SWT widgets is also applicable to Glimmer Custom Widgets written in Ruby. I recommend reading it:
[https://www.eclipse.org/articles/Article-Writing%20Your%20Own%20Widget/Writing%20Your%20Own%20Widget.htm](https://www.eclipse.org/articles/Article-Writing%20Your%20Own%20Widget/Writing%20Your%20Own%20Widget.htm)
Also, you may check out [Hello, Custom Widget!](#hello-custom-widget) for another example.
### Custom Shells
Custom shells are a kind of custom widgets that have shells only as the body root. They can be self-contained applications that may be opened and hidden/closed independently of the main app.
They may also be chained in a wizard fashion.
You can find out about [published Glimmer Custom Shells](https://github.com/AndyObtiva/glimmer-dsl-swt#gem-listing) by running the `glimmer list:gems:customshell` command
Example (you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
class WizardStep
include Glimmer::UI::CustomShell
options :number, :step_count
before_body {
@title = "Step #{number}"
}
body {
shell {
text "Wizard - #{@title}"
minimum_size 200, 100
fill_layout :vertical
label(:center) {
text @title
font height: 30
}
if number < step_count
button {
text "Go To Next Step"
on_widget_selected {
body_root.hide
}
}
end
}
}
end
shell { |app_shell|
text "Wizard"
minimum_size 200, 100
@current_step_number = 1
@wizard_steps = 5.times.map { |n|
wizard_step(number: n+1, step_count: 5) {
on_swt_hide {
if @current_step_number < 5
@current_step_number += 1
app_shell.hide
@wizard_steps[@current_step_number - 1].open
end
}
}
}
button {
text "Start"
font height: 40
on_widget_selected {
app_shell.hide
@wizard_steps[@current_step_number - 1].open
}
}
}.open
```
You may check out [Hello, Custom Shell!](#hello-custom-shell) for another example.
### Drag and Drop
Glimmer offers Drag and Drop support, thanks to [SWT](https://www.eclipse.org/swt/) and Glimmer's lightweight [DSL syntax](#glimmer-dsl-syntax).
You may learn more about SWT Drag and Drop support over here: [https://www.eclipse.org/articles/Article-SWT-DND/DND-in-SWT.html](https://www.eclipse.org/articles/Article-SWT-DND/DND-in-SWT.html)
To get started, simply follow these steps:
1. On the drag source widget, add `on_drag_set_data` [DragSourceListener](https://help.eclipse.org/2020-03/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/DragSourceListener.html) event handler block at minimum (you may also add `on_drag_start` and `on_drag_finished` if needed)
1. Set `event.data` to transfer via drag and drop inside the `on_drag_set_data` event handler block (defaults to `transfer` type of `:text`, as in a Ruby String)
1. On the drop target widget, add `on_drop` [DropTargetListener](https://help.eclipse.org/2020-03/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/DropTargetListener.html) event handler block at minimum (you may also add `on_drag_enter` [must set [`event.detail`](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/DropTargetEvent.html#detail) if added], `on_drag_over`, `on_drag_leave`, `on_drag_operation_changed` and `on_drop_accept` if needed)
1. Read `event.data` and consume it (e.g. change widget text) inside the `on_drop` event handler block.
Example (taken from [samples/hello/hello_drag_and_drop.rb](#hello-drag-and-drop) / you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
class Location
attr_accessor :country
def country_options
%w[USA Canada Mexico Columbia UK Australia Germany Italy Spain]
end
end
@location = Location.new
include Glimmer
shell {
text 'Hello, Drag and Drop!'
list {
selection bind(@location, :country)
on_drag_set_data { |event|
list = event.widget.getControl
event.data = list.getSelection.first
}
}
label(:center) {
text 'Drag a country here!'
font height: 20
on_drop { |event|
event.widget.getControl.setText(event.data)
}
}
}.open
```
![Hello Drag and Drop](images/glimmer-hello-drag-and-drop.gif)
Optional steps:
- Set a `transfer` property (defaults to `:text`). Values may be: :text (default), :html :image, :rtf, :url, and :file, or an array of multiple values. The `transfer` property will automatically convert your option into a [Transfer](https://help.eclipse.org/2020-03/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/Transfer.html) object as per the SWT API.
- Specify `drag_source_style` operation (may be: :drop_copy (default), :drop_link, :drop_move, :drop_none, or an array of multiple operations)
- Specify `drag_source_effect` (Check [DragSourceEffect](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/DragSourceEffect.html) SWT API for details)
- Specify `drop_target_style` operation (may be: :drop_copy (default), :drop_link, :drop_move, :drop_none, or an array of multiple operations)
- Specify `drop_target_effect` (Check [DropTargetEffect](https://help.eclipse.org/2020-06/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/dnd/DropTargetEffect.html) SWT API for details)
- Set drag operation in `event.detail` (e.g. DND::DROP_COPY) inside `on_drag_enter`
### Miscellaneous
#### Multi-DSL Support
Glimmer is a DSL engine that supports multiple DSLs (Domain Specific Languages):
- [SWT](https://github.com/AndyObtiva/glimmer-dsl-swt): Glimmer DSL for SWT (Desktop GUI)
- [Opal](https://github.com/AndyObtiva/glimmer-dsl-opal): Glimmer DSL for Opal (Web GUI Adapter for Desktop Apps)
- [XML](https://github.com/AndyObtiva/glimmer-dsl-xml): Glimmer DSL for XML (& HTML) - Useful with [SWT Browser Widget](#browser-widget)
- [CSS](https://github.com/AndyObtiva/glimmer-dsl-css): Glimmer DSL for CSS (Cascading Style Sheets) - Useful with [SWT Browser Widget](#browser-widget)
Glimmer automatically recognizes top-level keywords in each DSL and activates DSL accordingly. Glimmer allows mixing DSLs, which comes in handy when doing things like using the SWT Browser widget with XML and CSS. Once done processing a nested DSL top-level keyword, Glimmer switches back to the prior DSL automatically.
##### SWT
The SWT DSL was already covered in detail. However, for the sake of mixing DSLs, you need to know that the SWT DSL has the following top-level keywords:
- `shell`
- `display`
- `color`
- `observe`
- `async_exec`
- `sync_exec`
##### Opal
Full instructions are found in the [Opal](https://github.com/AndyObtiva/glimmer-dsl-opal) DSL page.
The [Opal](https://github.com/AndyObtiva/glimmer-dsl-opal) DSL is simply a web GUI adapter for desktop apps written in Glimmer. As such, it supports all the DSL keywords of the SWT DSL and shares the same top-level keywords.
##### XML
Simply start with `html` keyword and add HTML inside its block using Glimmer DSL syntax.
Once done, you may call `to_s`, `to_xml`, or `to_html` to get the formatted HTML output.
Here are all the Glimmer XML DSL top-level keywords:
- `html`
- `tag`: enables custom tag creation for exceptional cases by passing tag name as '_name' attribute
- `name_space`: enables namespacing html tags
Element properties are typically passed as a key/value hash (e.g. `section(id: 'main', class: 'accordion')`) . However, for properties like "selected" or "checked", you must leave value `nil` or otherwise pass in front of the hash (e.g. `input(:checked, type: 'checkbox')` )
Example (basic HTML / you may copy/paste in [`girb`](#girb-glimmer-irb-command)):
```ruby
@xml = html {
head {
meta(name: "viewport", content: "width=device-width, initial-scale=2.0")
}
body {
h1 { "Hello, World!" }
}
}
puts @xml
```
Output:
```