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# -*- indent-tabs-mode: nil -*-
# Original copyright
#
# canvas-curve.c: bezier curve demo.
#
# Copyright (C) 2002 Mark McLoughlin
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
#
# Authors:
# Mark McLoughlin <mark@skynet.ie>
class CanvasSampleBezierCurve < Gtk::VBox
STATE_INIT = 0
STATE_FIRST_PRESS = 1
STATE_FIRST_RELEASE = 2
STATE_SECOND_PRESS = 3
def draw_curve(item, x, y)
root = item.parent
case @current_state
when STATE_INIT
@current_points = [] if @current_points.nil?
@current_points[0] = x
@current_points[1] = y
when STATE_FIRST_PRESS
@current_points[2] = x
@current_points[3] = y
path_def = Gnome::CanvasPathDef.new()
path_def.moveto(@current_points[0], @current_points[1])
path_def.lineto(@current_points[2], @current_points[3])
unless @current_item.nil?
@current_item.set({:bpath => path_def})
else
@current_item = Gnome::CanvasBpath.new(root,
{:bpath => path_def,
:outline_color => "blue",
:width_pixels => 5,
:cap_style => Gdk::GC::CAP_ROUND})
@current_item.signal_connect("event") do |item, event|
item_event(item, event)
end
end
when STATE_FIRST_RELEASE
@current_points[4] = x
@current_points[5] = y
path_def = Gnome::CanvasPathDef.new()
path_def.moveto(@current_points[0], @current_points[1])
path_def.curveto(@current_points[4], @current_points[5],
@current_points[4], @current_points[5],
@current_points[2], @current_points[3])
@current_item.set({:bpath => path_def})
when STATE_SECOND_PRESS
@current_points[6] = x;
@current_points[7] = y;
path_def = Gnome::CanvasPathDef.new();
path_def.moveto(@current_points[0], @current_points[1])
path_def.curveto(@current_points[4], @current_points[5],
@current_points[6], @current_points[7],
@current_points[2], @current_points[3])
@current_item.set({:bpath => path_def})
@current_item = nil
else
raise "not reached here"
end
end
def item_event(item, event)
if (event.event_type == Gdk::Event::BUTTON_PRESS &&
event.button == 1 &&
(event.state & Gdk::Window::SHIFT_MASK == Gdk::Window::SHIFT_MASK))
if (item == @current_item)
@current_item = nil
@current_state = STATE_INIT
end
item.destroy()
return true
end
false
end
def canvas_event(item, event)
case event.event_type
when Gdk::Event::BUTTON_PRESS
return false if event.button != 1
case @current_state
when STATE_INIT
draw_curve(item, event.x, event.y)
@current_state = STATE_FIRST_PRESS
when STATE_FIRST_RELEASE
draw_curve(item, event.x, event.y)
@current_state = STATE_SECOND_PRESS
when STATE_SECOND_PRESS
draw_curve(item, event.x, event.y)
@current_state = STATE_INIT
else
raise format("shouldn't have reached here %d", @current_state)
end
when Gdk::Event::BUTTON_RELEASE
return false if event.button != 1
case @current_state
when STATE_FIRST_PRESS
draw_curve(item, event.x, event.y)
@current_state = STATE_FIRST_RELEASE
end
when Gdk::Event::MOTION_NOTIFY
case @current_state
when STATE_FIRST_PRESS
draw_curve(item, event.x, event.y)
end
end
false
end
def create_canvas(aa)
Gtk::Widget.push_colormap(Gdk::RGB.colormap())
canvas = Gnome::Canvas.new(aa)
canvas.set_size_request(600, 250) #?
canvas.set_scroll_region(0, 0, 600, 250)
canvas.show()
root = canvas.root
item = Gnome::CanvasRect.new(root,
{:outline_color => "black",
:fill_color => "white",
:x1 => 0.0,
:y1 => 0.0,
:x2 => 600.0,
:y2 => 250.0})
Gnome::CanvasText.new(root,
{:text => aa ? "AntiAlias" : "Non-AntiAlias",
:x => 270.0,
:y => 5.0,
:font => "Sans 12",
:anchor => Gtk::ANCHOR_N,
:fill_color => "black"})
Gtk::Widget.pop_colormap()
item.signal_connect("event") do |item, event|
canvas_event(item, event)
end
frame = Gtk::Frame.new()
frame.shadow_type = Gtk::SHADOW_IN
frame.add(canvas)
frame
end
def initialize
super(false, 4)
self.border_width = 4
self.show()
@current_state = STATE_INIT
label = Gtk::Label.new(<<EOS)
Drag a line with button 1. Then mark 2 control points with
button 1. Shift+click with button 1 to destroy the curve.
EOS
self.pack_start(label, false, false, 0)
label.show()
canvas = create_canvas(false)
self.pack_start(canvas, true, true, 0)
canvas.show()
aa_canvas = create_canvas(true)
self.pack_start(aa_canvas, true, true, 0)
aa_canvas.show()
end
end
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