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#!/usr/bin/env ruby
=begin
pangolayout.rb - Ruby/GTK sample script.
Copyright (c) 2005-2015 Ruby-GNOME2 Project Team
This program is licenced under the same licence as Ruby-GNOME2.
=end
require "gtk3"
RADIUS = 80
N_WORDS = 16
HEIGHT = 400
WIDTH = 400
class PaintableWindow < Gtk::Window
attr_reader :x, :y, :width, :height
def initialize(name)
super(name)
set_app_paintable(true)
set_decorated(true)
set_default_size(WIDTH, HEIGHT)
signal_connect("destroy") { Gtk.main_quit }
set_double_buffered(false)
# Get the size attributes when the window is resized
signal_connect "size-allocate" do |_widget, rectangle|
@x = rectangle.x
@y = rectangle.y
@width = rectangle.width
@height = rectangle.height
end
signal_connect "screen-changed" do |widget, _old_screen|
screen_changed(widget)
end
screen_changed(self)
end
def supports_alpha?
@supports_alpha
end
private
def screen_changed(widget)
visual = widget.screen.rgba_visual
if visual && widget.screen.composited?
set_visual(visual)
@supports_alpha = true
else
set_visual(widget.screen.system_visual)
@supports_alpha = false
end
end
end
pangolayout = PaintableWindow.new("Pango Render")
pangolayout.signal_connect "draw" do |widget, cr|
# Redraw on a clean destination
# http://cairographics.org/manual/cairo-cairo-t.html#cairo-operator-t
cr.set_operator(Cairo::OPERATOR_SOURCE)
if widget.supports_alpha?
cr.set_source_rgba(0, 0, 0, 0.3)
else
cr.set_source_rgb(1, 1, 1)
end
cr.paint
device_radius = [widget.width, widget.height].min / 6.0
cr.translate(device_radius + (widget.width - 2 * device_radius) / 2.0,
device_radius + (widget.height - 2 * device_radius) / 2.0)
cr.scale(device_radius / RADIUS, device_radius / RADIUS)
pango_layout = cr.create_pango_layout
pango_layout.text = "Ruby-GNOME2"
pango_layout.font_description = Pango::FontDescription.new("Sans Bold 14")
N_WORDS.times do |i|
angle = 360 * i / N_WORDS.to_f
cr.set_source_rgb((65_535 * rand) / 65_355,
(65_535 * rand) / 65_355,
(65_535 * rand) / 65_355)
cr.rotate((angle * Math::PI) / 180.0)
cr.update_pango_layout(pango_layout)
width, _height = pango_layout.size
cr.move_to((width / 2) / Pango::SCALE, RADIUS)
cr.show_pango_layout(pango_layout)
end
end
pangolayout.show
Gtk.main
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