ruby-****@sourc*****
ruby-****@sourc*****
2013年 3月 23日 (土) 14:48:54 JST
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REMOTE_ADDR = 70.49.48.128
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk2-dancr-rbcatut
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@@ -105,6 +105,89 @@
As you can see, if you run this program it displays an empty grey cairo drawing area.
+ However, as the title of this paragraph (12.3.0.1) suggests, we need the Gtk/Cairo framework because we would like to run some cairo code of our own. It would be desirable, if we had a template file into which we could always include the new code. This is what we will explain next.
+
+# (12.3.0.1.2)
+:The Template Ruby File To Run Arbitrary Cairo Code:
+ (12.3.0.1.2){{br}}
+
+ Indeed, to create the template we are going to use the code shown in the above 'minimal-rb-cr.rb'program. Eventually, the new template will act as wrapper code, with a stub method called((*draw(cr, drawing_area).*)) Basically, the template is an executable program in which you create a new class inheriting directly from the CairoWindow, and overriding its((*draw*))method. This 'draw' method is where you will place your cairo code. Lets look at the empty ready to use template:
+
+ #!/usr/bin/env ruby
+
+ $: << '~/work/HikiLib'
+ require 'hiki2-gtk-w-cairo.rb'
+ include HikiGtk
+
+ class MyCairoCodeClass < CairoWindow # Your own CairoWindow class
+ def draw(cr, drawing_area) # Override the draw method
+ width, height = drawing_area.window.size # You will likely need w, h
+ o o o # Your code comes here
+ end #
+ end #
+
+ window=MyCairoCodeClass.new # Replace 'CairoWindow' with your new class name.
+ # Optionally, supply the your name to the constructor.
+ window.show_all
+ Gtk.main
+
+ The lines containing comments are the additions that turn the above 'minimal-rb-cr.rb' program into our template file.
+
+ :A Real Life Example With Runing Cairo Code
+
+ (12.3.0.1.2.2) {{image_right("1203-smiley-face-s1.png")}}
+ In Michael Urman's Cairo tutorial called ((<Cairo Tutorial for PyGTK Programmers|URL:http://www.tortall.net/mu/wiki/PyGTKCairoTutorial>)), where Nichael also creates a similar Gtk/Cairo framework as is ours, you can find a neat piece of Python cairo code generating a((*smiley face.*)) I translated his smiley face Python code to Ruby, and run it in our Ruby Gtk/Cairo wrapper.
+
+ ((*SmileyFace.rb*))
+
+ #!/usr/bin/env ruby
+
+ $: << '~/work/HikiLib'
+ require 'hiki2-gtk-w-cairo.rb'
+ include HikiGtk
+
+ class SmileyFace < CairoWindow
+
+ def draw(cr, drawing_area)
+
+ width, height = drawing_area.window.size
+
+ # Fill the background with a colour of your choice
+ cr.set_source_rgb(0.5, 0.5, 0.9)
+ cr.rectangle(0, 0, width, height)
+ cr.fill()
+
+ # draw a rectangle
+ cr.set_source_rgb(1.0, 1.0, 1.0)
+ cr.rectangle(10, 10, width - 20, height - 20)
+ cr.fill()
+
+ # and a circle
+ cr.set_source_rgb(1.0, 0.0, 0.0)
+ radius = [width, height].min
+ cr.arc(width / 2.0, height / 2.0, radius / 2.0 - 20, 0, 2 * Math::PI)
+ cr.stroke()
+ cr.arc(width / 2.0, height / 2.0, radius / 3.0 - 10, Math::PI / 3, 2 * Math::PI / 3)
+ cr.stroke()
+
+ # draw lines
+ cr.set_source_rgb(0.0, 0.0, 0.8)
+ cr.move_to(width / 3.0, height / 3.0)
+ cr.rel_line_to(0, height / 6.0)
+ cr.move_to(2 * width / 3.0, height / 3.0)
+ cr.rel_line_to(0, height / 6.0)
+ cr.stroke()
+ end
+ end
+
+ w=SmileyFace.new("Smiley Face")
+ w.show_all
+ w.set_size_request(75, 50)
+ Gtk.main
+
+
+
+{{br}}