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# Copyright (c) 2005 Ruby-GNOME2 Project Team
# This program is licenced under the same licence as Ruby-GNOME2.
#
# $Id: cairo-curve-rectangle.rb,v 1.1 2005/10/12 05:38:30 ktou Exp $
=begin
= cairo/Curve Rectangle
This demo shows how to use GDK and cairo to draw curve rectangle.
From http://cairographics.org/samples/curve_rectangle.html.
=end
require 'common'
module Demo
class CairoCurveRectangle < CairoWindow
# a custom shape, that could be wrapped in a function
X0 = 0.1 #< parameters like Cairo::Context#rectangle
Y0 = 0.1
RECT_WIDTH = 0.8
RECT_HEIGHT = 0.8
RADIUS = 0.4 #< and an approximate curvature radius
X1 = X0 + RECT_WIDTH
Y1 = Y0 + RECT_HEIGHT
def initialize
super('cairo curve rectangle')
end
def draw(cr)
return if (RECT_WIDTH <= 0 || RECT_HEIGHT <= 0)
if (RECT_WIDTH / 2 < RADIUS)
if (RECT_HEIGHT / 2 < RADIUS)
cr.move_to(X0, (Y0 + Y1) / 2)
cr.curve_to(X0 ,Y0, X0, Y0, (X0 + X1) / 2, Y0)
cr.curve_to(X1, Y0, X1, Y0, X1, (Y0 + Y1) / 2)
cr.curve_to(X1, Y1, X1, Y1, (X1 + X0) / 2, Y1)
cr.curve_to(X0, Y1, X0, Y1, X0, (Y0 + Y1) / 2)
else
cr.move_to(X0, Y0 + RADIUS)
cr.curve_to(X0 ,Y0, X0, Y0, (X0 + X1) / 2, Y0)
cr.curve_to(X1, Y0, X1, Y0, X1, Y0 + RADIUS)
cr.line_to(X1 , Y1 - RADIUS)
cr.curve_to(X1, Y1, X1, Y1, (X1 + X0) / 2, Y1)
cr.curve_to(X0, Y1, X0, Y1, X0, Y1- RADIUS)
end
else
if (RECT_HEIGHT / 2 < RADIUS)
cr.move_to(X0, (Y0 + Y1) / 2)
cr.curve_to(X0, Y0, X0 , Y0, X0 + RADIUS, Y0)
cr.line_to(X1 - RADIUS, Y0)
cr.curve_to(X1, Y0, X1, Y0, X1, (Y0 + Y1) / 2)
cr.curve_to(X1, Y1, X1, Y1, X1 - RADIUS, Y1)
cr.line_to(X0 + RADIUS, Y1)
cr.curve_to(X0, Y1, X0, Y1, X0, (Y0 + Y1) / 2)
else
cr.move_to(X0, Y0 + RADIUS)
cr.curve_to(X0 , Y0, X0 , Y0, X0 + RADIUS, Y0)
cr.line_to(X1 - RADIUS, Y0)
cr.curve_to(X1, Y0, X1, Y0, X1, Y0 + RADIUS)
cr.line_to(X1 , Y1 - RADIUS)
cr.curve_to(X1, Y1, X1, Y1, X1 - RADIUS, Y1)
cr.line_to(X0 + RADIUS, Y1)
cr.curve_to(X0, Y1, X0, Y1, X0, Y1- RADIUS)
end
end
cr.close_path
cr.set_source_rgba(0.5,0.5,1)
cr.fill_preserve
cr.set_source_rgba(0.5, 0, 0, 0.5)
cr.stroke
end
end
end
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