Программирование на языке Ruby - [188]

:

• demo.rb, квадрант 1

• individual-i.rb, квадрант 3

• gettysburg.rb, квадрант 4

Четвертая страница (в квадранте 2) не имеет прямого аналога среди демонстрационных программ, она ближе всего к программе chunkybacon.rb.

Весь код приведен в листинге 15.11, а результат показан на рис. 15.4. Пример довольно длинный, мы подробно обсудим его ниже.

Листинг 15.11. Создание демонстрационного документа

require 'rubygems'
require 'pdf/writer'

def quadrant(pdf, quad)
 raise unless block_given?

 mx = pdf.absolute_x_middle
 my = pdf.absolute_y_middle
 pdf.save_state
 case quad
  when :ul
   pdf.translate_axis 0, my
  when :ur
   pdf.translate_axis mx, my
  when :ll
   nil # no translation needed
  when :lr
   pdf.translate_axis mx, 0
 end

 pdf.scale_axis(0.5, 0.5)
 pdf.у = pdf.page_height
 yield
 pdf.restore_state
end

pdf = PDF::Writer.new
pdf.select_font("Times-Roman",
 rencoding => "WinAnsiEncoding",
 differences => { 0x01 => "lozenge" })

mx = pdf.absolute_x_middle
my = pdf.absolute_y_middle

pdf.line(0, my, pdf.page_width, my).stroke
pdf.line(mx, 0, mx, pdf.page_height).stroke

# Левый верхний: Demo (UL).

quadrant(pdf, :ul) do
 x = pdf.absolute_right_margin
 r1 = 25

 40.step(1, -3) do |xw|
  tone = 1.0 - (xw / 40.0) * 0.2
  pdf.stroke_style(PDF::Writer::StrokeStyle.new(xw))
  pdf.stroke_color(Color::RGB.from_fraction(1, tone, tone))
  pdf.line(x, pdf.bottom_margin, x,
   pdf.absolute_top_margin).stroke
  x -= xw+2
 end

 40.step(1, -3) do |xw|
  tone = 1.0 - (xw / 40.0) * 0.2
  pdf.stroke_style(PDF::Writer::StrokeStyle.new(xw))
  pdf.stroke_color(Color::RGB.from_fraction(1, tone, tone))
  pdf.circle_at(pdf.left_margin + 10, pdf.margin_height - 15,
   r1).stroke
  r1 += xw
 end
 pdf.stroke_color(Color::RGB::Black)

 x = pdf.absolute_left_margin
 y = pdf.absolute_bottom_margin
 w = pdf.margin_width
 h = pdf.margin_height
 pdf.rectangle(x, y, w, h).stroke

 text = "The Ruby Way"

 y = pdf.absolute_top_margin
 50.step(5, -5) do |size|
  height = pdf.font_height(size)
  y -= height
  pdf.add_text(pdf.left_margin + 10, y, text, size)
 end

 (0...360).step(20) do |angle|
  pdf.fill_color(Color::RGB.from_fraction(rand, rand, rand))
  pdf.add_text(300 + Math.cos(PDF::Math.deg2rad(angle)) * 40,
   300 + Math.sin(PDF::Math.deg2rad(angle)) * 40,
   text, 20, angle)
 end
end

pdf.fill_color Color::RGB::Black

# Правый верхний: Grampian Highlands (UR).

quadrant(pdf, :ur) do
 pdf.image("grampian-highlands.jpg",
  :height => pdf.margin_height,
  :resize => :width)
 pdf.text("The Grampian Highlands, Scotland",
  justification => :center,
  :font_size => 36)
 pdf.text("\001August 2001\001", :justification => :center,
  :font_size => 24)
 pdf.move_pointer(24)
 info = <<-'EOS'.split($/).join(" ").squeeze(" ")
This picture was taken during a driving vacation through the
Scottish highlands in August 2001 by Austin Ziegler.
 EOS
 pdf.text(info, :justification => :full, :font_size => 16,
  :left => 100, :right => 100)
end

pdf.fill_color Color::RGB::Black

# Левый нижний: Individual-I (LL).

quadrant(pdf, :ll) do
 require 'color/palette/monocontrast'

 class IndividualI
  def initialize(size = 100)
   @size = size
  end

  # Размер буквы "i" в пунктах.
  attr_accessor :size

  def half_i(pdf)
   pdf.move_to(0, 82)
   pdf.line_to(0, 78)
   pdf.line_to(9, 78)
   pdf.line_to(9, 28)
   pdf.line_to(0, 28)
   pdf.line_to(0, 23)
   pdf.line_to(18, 23)
   pdf.line_to(18, 82)
   pdf.fill
  end
  private :half_i

  def draw(pdf, x, y)
   pdf.save_state
   pdf.translate_axis(x, y)
   pdf.scale_axis(1 * (@size / 100.0), -1 * (@size / 100.0))

   pdf.circle_at(20, 10, 7.5)
   pdf.fill

   half_i(pdf)

   pdf.translate_axis(40, 0)
   pdf.scale_axis(-1, 1)

   half_i(pdf)
   pdf.restore_state
  end
 end

 ii = IndividualI.new(24)

 x = pdf.absolute_left_margin
 y = pdf.absolute_top_margin
 bg = Color::RGB.from_fraction(rand, rand, rand)
 fg = Color::RGB.from_fraction(rand, rand, rand)
 pal = Color::Palette::MonoContrast.new(bg, fg)

 sz = 24

 (-5..5).each do |col|
  pdf.fill_color pal.background[col]
  ii.draw(pdf, x, y)
  ii.size += sz
  x += sz / 2.0
  y -= sz / 2.0
  pdf.fill_color
  pal.foreground[col]
  ii.draw(pdf, x, y)
  x += sz / 2.0
  y -= sz / 2.0
  ii.size += sz
 end
end

pdf.fill_color Color::RGB::Black

# Правый нижний: Gettysburg Address (LR).
# Это текст Геттисбергского обращения Авраама Линкольна.

quadrant(pdf, :lr) do
 pdf.text("The Gettysburg Address\n\n",
  :font_size => 36, justification => :center)
 y0 = pdf.y + 18
 speech = <<-'EOS'.split($/). join(" ").squeeze(" ")
Four score and seven years ago our fathers brought forth on
this continent a new nation, conceived in liberty and
dedicated to the proposition that all men are created equal.
Now we are engaged in a great civil war, testing whether
that nation or any nation so conceived and so dedicated can
long endure. We are met on a great battlefield of that war.
We have come to dedicate a portion of that field as a final
resting-place for those who here gave their lives that that
nation might live. It is altogether fitting and proper that
we should do this. But in a larger sense, we cannot
dedicate, we cannot consecrate, we cannot hallow
this ground. The brave men, living and dead who struggled here