# encoding: utf-8
# text/rectangle.rb : Implements text boxes
#
# Copyright November 2009, Daniel Nelson. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.
#
module Prawn
module Text
# Draws the requested text into a box. When the text overflows
# the rectangle, you can display ellipses, shrink to fit, or
# truncate the text. Text boxes are independent of the document
# y position.
#
# == Encoding
#
# Note that strings passed to this function should be encoded as UTF-8.
# If you get unexpected characters appearing in your rendered document,
# check this.
#
# If the current font is a built-in one, although the string must be
# encoded as UTF-8, only characters that are available in WinAnsi
# are allowed.
#
# If an empty box is rendered to your PDF instead of the character you
# wanted it usually means the current font doesn't include that character.
#
# == Options (default values marked in [])
#
# :kerning:: boolean. Whether or not to use kerning (if it
# is available with the current font)
# [value of document.default_kerning?]
# :size:: number. The font size to use. [current font
# size]
# :character_spacing:: number. The amount of space to add
# to or remove from the default character
# spacing. [0]
# :style:: The style to use. The requested style must be part of
# the current font familly. [current style]
#
# :at::
# [x, y]. The upper left corner of the box
# [@document.bounds.left, @document.bounds.top]
# :width::
# number. The width of the box [@document.bounds.right - @at[0]]
# :height::
# number. The height of the box [@at[1] - @document.bounds.bottom]
# :align::
# :left, :center, :right, or
# :justify Alignment within the bounding box [:left]
# :valign::
# :top, :center, or :bottom. Vertical
# alignment within the bounding box [:top]
#
# :rotate::
# number. The angle to rotate the text
# :rotate_around::
# :center, :upper_left, :upper_right,
# :lower_right, or :lower_left. The point around which
# to rotate the text [:upper_left]
# :leading::
# number. Additional space between lines [0]
# :single_line::
# boolean. If true, then only the first line will be drawn [false]
# :skip_encoding::
# boolean [false]
# :overflow::
# :truncate, :shrink_to_fit, :expand, or
# :ellipses. This controls the behavior when the amount of text
# exceeds the available space. :ellipses [:truncate]
# :min_font_size::
# number. The minimum font size to use when :overflow is set to
# :shrink_to_fit (that is the font size will not be reduced to less than
# this value, even if it means that some text will be cut off). [5]
#
# == Returns
#
# Returns any text that did not print under the current settings.
#
# NOTE: if an AFM font is used, then the returned text is encoded in
# WinAnsi. Subsequent calls to text_box that pass this returned text back
# into text box must include a :skip_encoding => true option. This is
# unnecessary when using TTF fonts because those operate on UTF-8 encoding.
#
# == Exceptions
#
# Raises Prawn::Errrors::CannotFit if not wide enough to print
# any text
#
def text_box(string, options)
Text::Box.new(string, options.merge(:document => self)).render
end
# Generally, one would use the Prawn::Text#text_box convenience
# method. However, using Text::Box.new in conjunction with
# #render(:dry_run=> true) enables one to do look-ahead calculations prior
# to placing text on the page, or to determine how much vertical space was
# consumed by the printed text
#
class Box
include Prawn::Core::Text::Wrap
def valid_options
Prawn::Core::Text::VALID_OPTIONS + [:at, :height, :width,
:align, :valign,
:rotate, :rotate_around,
:overflow, :min_font_size,
:leading, :character_spacing,
:single_line,
:skip_encoding,
:document]
end
# The text that was successfully printed (or, if dry_run was
# used, the test that would have been successfully printed)
attr_reader :text
# The upper left corner of the text box
attr_reader :at
# The line height of the last line printed
attr_reader :line_height
# The height of the ascender of the last line printed
attr_reader :ascender
# The height of the descender of the last line printed
attr_reader :descender
# The leading used during printing
attr_reader :leading
# Extend Prawn::Text::Box
#
# Example (see Prawn::Text::Core::Wrap for what is required
# of the wrap method if you want to override the default
# wrapping algorithm):
#
# module MyWrap
#
# def wrap
# @text = nil
# @line_height = @document.font.height
# @descender = @document.font.descender
# @ascender = @document.font.ascender
# @baseline_y = -@ascender
# draw_line("all your base are belong to us")
# ""
# end
#
# end
#
# Prawn::Text::Box.extensions << MyWrap
#
# box = Prawn::Text::Box.new('hello world')
# box.render('why can't I print anything other than' +
# '"all your base are belong to us"?')
#
#
def self.extensions
@extensions ||= []
end
def self.inherited(base) #:nodoc:
extensions.each { |e| base.extensions << e }
end
# See Prawn::Text#text_box for valid options
#
def initialize(text, options={})
@inked = false
Prawn.verify_options(valid_options, options)
options = options.dup
self.class.extensions.reverse_each { |e| extend e }
@overflow = options[:overflow] || :truncate
self.original_text = text
@text = nil
@document = options[:document]
@at = options[:at] ||
[@document.bounds.left, @document.bounds.top]
@width = options[:width] ||
@document.bounds.right - @at[0]
@height = options[:height] ||
@at[1] - @document.bounds.bottom
@align = options[:align] || :left
@vertical_align = options[:valign] || :top
@leading = options[:leading] || @document.default_leading?
@character_spacing = options[:character_spacing] ||
@document.character_spacing
@rotate = options[:rotate] || 0
@rotate_around = options[:rotate_around] || :upper_left
@single_line = options[:single_line]
@skip_encoding = options[:skip_encoding] || @document.skip_encoding
if @overflow == :expand
# if set to expand, then we simply set the bottom
# as the bottom of the document bounds, since that
# is the maximum we should expand to
@height = @at[1] - @document.bounds.bottom
@overflow = :truncate
end
@min_font_size = options[:min_font_size] || 5
if options[:kerning].nil? then
options[:kerning] = @document.default_kerning?
end
@options = { :kerning => options[:kerning],
:size => options[:size],
:style => options[:style] }
super(text, options)
end
# Render text to the document based on the settings defined in initialize.
#
# In order to facilitate look-ahead calculations, render accepts
# a :dry_run => true option. If provided, then everything is
# executed as if rendering, with the exception that nothing is drawn on
# the page. Useful for look-ahead computations of height, unprinted text,
# etc.
#
# Returns any text that did not print under the current settings
#
def render(flags={})
unprinted_text = ''
@document.save_font do
@document.character_spacing(@character_spacing) do
process_options
if @skip_encoding
text = original_text
else
text = normalize_encoding
end
@document.font_size(@font_size) do
shrink_to_fit(text) if @overflow == :shrink_to_fit
process_vertical_alignment(text)
@inked = true unless flags[:dry_run]
if @rotate != 0 && @inked
unprinted_text = render_rotated(text)
else
unprinted_text = wrap(text)
end
@inked = false
end
end
end
unprinted_text
end
# The height actually used during the previous render
#
def height
return 0 if @baseline_y.nil? || @descender.nil?
# baseline is already pushed down one line below the current
# line, so we need to subtract line line_height and leading,
# but we need to add in the descender since baseline is
# above the descender
@baseline_y.abs - @ascender - @leading
end
# The width available at this point in the box
#
def available_width
@width
end
def draw_line(line_to_print, line_width=0, word_spacing=0, include_ellipses=false) #:nodoc:
insert_ellipses(line_to_print) if include_ellipses
case(@align)
when :left, :justify
x = @at[0]
when :center
x = @at[0] + @width * 0.5 - line_width * 0.5
when :right
x = @at[0] + @width - line_width
end
y = @at[1] + @baseline_y
if @inked
@document.word_spacing(word_spacing) {
@document.character_spacing(@character_spacing) {
@document.draw_text!(line_to_print, :at => [x, y],
:kerning => @kerning)
}
}
end
line_to_print
end
private
def normalize_encoding
@document.font.normalize_encoding(@original_string)
end
def original_text
@original_string
end
def original_text=(string)
@original_string = string.dup
end
def process_vertical_alignment(text)
return if @vertical_align == :top
wrap(text)
case @vertical_align
when :center
@at[1] = @at[1] - (@height - height) * 0.5
when :bottom
@at[1] = @at[1] - (@height - height)
end
@height = height
end
# Decrease the font size until the text fits or the min font
# size is reached
def shrink_to_fit(text)
while (unprinted_text = wrap(text)).length > 0 &&
@font_size > @min_font_size
@font_size -= 0.5
@document.font_size = @font_size
end
end
def process_options
# must be performed within a save_font bock because
# document.process_text_options sets the font
@document.process_text_options(@options)
@font_size = @options[:size]
@kerning = @options[:kerning]
end
def render_rotated(text)
unprinted_text = ''
case @rotate_around
when :center
x = @at[0] + @width * 0.5
y = @at[1] - @height * 0.5
when :upper_right
x = @at[0] + @width
y = @at[1]
when :lower_right
x = @at[0] + @width
y = @at[1] - @height
when :lower_left
x = @at[0]
y = @at[1] - @height
else
x = @at[0]
y = @at[1]
end
@document.rotate(@rotate, :origin => [x, y]) do
unprinted_text = wrap(text)
end
unprinted_text
end
def last_line?
@baseline_y.abs + @descender > @height - @line_height
end
def insert_ellipses(line_to_print)
if @document.width_of(line_to_print + "...",
:kerning => @kerning) < available_width
line_to_print.insert(-1, "...")
else
line_to_print[-3..-1] = "..." if line_to_print.length > 3
end
end
end
end
end