#!/usr/bin/env python

# An example of an animation done with cairo and Gtk+
#
# Copyright (C) 2013  Antonio Ospite <ospite@studenti.unina.it>
#
# 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.

# References:
# http://wiki.laptop.org/go/PyGTK/Smooth_Animation_with_PyGTK

import gi

gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, GObject, Gio

import math
import colorsys


class AnimatedCanvas(Gtk.DrawingArea):
    def __init__(self,  width, height, *args, **kwargs):
        super(AnimatedCanvas, self).__init__(*args, **kwargs)

        self.width = width
        self.height = height

        self.x_offset = 2
        self.y_offset = 3
        self.radius = 10
        self.border = 4

        self.x = self.radius + self.border
        self.y = self.radius + self.border

        self.set_size_request(width, height)
        self.connect('draw', self.do_draw_cb)
        self.connect('configure-event', self.do_configure_event_cb)

        fps = 30
        GObject.timeout_add(1000 / fps, self.update)

    def update(self):
        if self.x - self.radius - self.border < 0 or \
           self.x + self.radius + self.border > self.width:
            self.x_offset *= -1

        if self.y - self.radius - self.border < 0 or \
           self.y + self.radius + self.border > self.height:
            self.y_offset *= -1

        self.x += self.x_offset
        self.y += self.y_offset

        self.queue_draw()
        return True

    def do_configure_event_cb(self, widget, event):
        self.width = event.width
        self.height = event.height

    def do_draw_cb(self, widget, cr):

        cr.rectangle(0, 0, self.width, self.height)
        cr.set_source_rgb(1.0, 0.5, 0.5)
        cr.fill()

        cr.arc(self.x, self.y, self.radius, 0, 2 * math.pi)

        cr.set_line_width(self.border)

        _h = self.x / float(self.width)
        _l = 0.5
        _s = self.y / float(self.height)
        _r, _g, _b = colorsys.hls_to_rgb(_h, _l, _s)
        cr.set_source_rgb(_r, _g, _b)
        cr.fill_preserve()

        cr.set_source_rgb(0, 0, 0)
        cr.stroke()


class AnimatedApp(Gtk.Application):
    def __init__(self, title, width, height, *args, **kwargs):
        super(AnimatedApp, self).__init__(*args, **kwargs)
        self.connect("activate", self.on_activate)
        self.title = title
        self.width = width
        self.height = height

    def on_activate(self, data=None):
        window = Gtk.Window(type=Gtk.WindowType.TOPLEVEL)
        window.set_title(self.title)

        canvas = AnimatedCanvas(self.width, self.height)
        window.add(canvas)
        window.show_all()
        self.add_window(window)


if __name__ == "__main__":
    app = AnimatedApp(
        "AnimatedApp", 640, 480,
        application_id="apps.test.animatedapp",
        flags=Gio.ApplicationFlags.FLAGS_NONE)
    app.run(None)