class Demo::CairoArcNegative

Constants

ANGLE1
ANGLE2
CENTER_X
CENTER_Y
RADIUS

Public Class Methods

new() click to toggle source
Calls superclass method
# File gtk2/sample/gtk-demo/cairo-arc-negative.rb, line 21
def initialize
  super('cairo arc_negative')
end

Public Instance Methods

draw(cr) click to toggle source
# File gtk2/sample/gtk-demo/cairo-arc-negative.rb, line 25
def draw(cr)
  cr.arc_negative(CENTER_X, CENTER_Y, RADIUS, ANGLE1, ANGLE2)
  cr.stroke
  
  # draw helping lines
  cr.set_source_rgba(1, 0.2, 0.2, 0.6)
  cr.arc(CENTER_X, CENTER_Y, 0.05, 0, 2 * Math::PI)
  cr.fill
  cr.set_line_width(0.03)
  cr.arc(CENTER_X, CENTER_Y, RADIUS, ANGLE1, ANGLE1)
  cr.line_to(CENTER_X, CENTER_Y)
  cr.arc(CENTER_X, CENTER_Y, RADIUS, ANGLE2, ANGLE2)
  cr.line_to(CENTER_X, CENTER_Y)
  cr.stroke
end