# Copyright (C) 2007, Red Hat, Inc. # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2 of the License, or (at your option) any later version. # # This library 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 # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the # Free Software Foundation, Inc., 59 Temple Place - Suite 330, # Boston, MA 02111-1307, USA. """ The animator module provides a simple framwork to create animations. Example: Animate the size of a window:: from gi.repository import Gtk from sugar3.graphics.animator import Animator, Animation # Construct a 5 second animator animator = Animator(5) # Construct a window to animate w = Gtk.Window() w.connect('destroy', Gtk.main_quit) # Start the animation when the window is shown w.connect('realize', lambda self: animator.start()) w.show() # Create an animation subclass to animate the widget class SizeAnimation(Animation): def __init__(self): # Tell the animation to give us values between 20 and # 420 during the animation Animation.__init__(self, 20, 420) def next_frame(self, frame): size = int(frame) w.resize(size, size) # Add the animation the the animator animation = SizeAnimation() animator.add(animation) # The animation needs to run inside a GObject main loop Gtk.main() STABLE. """ import time from gi.repository import GObject from gi.repository import GLib EASE_OUT_EXPO = 0 EASE_IN_EXPO = 1 class Animator(GObject.GObject): ''' The animator class manages the the timing for calling the animations. The animations can be added using the `add` function and then started with the `start` function. If multiple animations are added, then they will be played back at the same time and rate as each other. The `completed` signal is emitted upon the completion of the animation and also when the `stop` function is called. Args: duration (float): the duration of the animation in seconds fps (int, optional): the number of animation callbacks to make per second (frames per second) easing (int): the desired easing mode, either `EASE_OUT_EXPO` or `EASE_IN_EXPO` .. note:: When creating an animation, take into account the limited cpu power on some devices, such as the XO. Setting the fps too high on can use signifigant cpu usage on the XO. ''' __gsignals__ = { 'completed': (GObject.SignalFlags.RUN_FIRST, None, ([])), } def __init__(self, duration, fps=20, easing=EASE_OUT_EXPO): GObject.GObject.__init__(self) self._animations = [] self._duration = duration self._interval = 1.0 / fps self._easing = easing self._timeout_sid = 0 self._start_time = None def add(self, animation): ''' Add an animation to this animator Args: animation (:class:`sugar3.graphics.animator.Animation`): the animation instance to add ''' self._animations.append(animation) def remove_all(self): ''' Remove all animations and stop this animator ''' self.stop() self._animations = [] def start(self): ''' Start the animation running. This will stop and restart the animation if the animation is currently running ''' if self._timeout_sid: self.stop() self._start_time = time.time() self._timeout_sid = GLib.timeout_add( int(self._interval * 1000), self._next_frame_cb) def stop(self): ''' Stop the animation and emit the `completed` signal ''' if self._timeout_sid: GObject.source_remove(self._timeout_sid) self._timeout_sid = 0 self.emit('completed') def _next_frame_cb(self): current_time = min(self._duration, time.time() - self._start_time) current_time = max(current_time, 0.0) for animation in self._animations: animation.do_frame(current_time, self._duration, self._easing) if current_time == self._duration: self.stop() return False else: return True class Animation(object): ''' The animation class is a base class for creating an animation. It should be subclassed. Subclasses should specify a `next_frame` function to set the required properties based on the animation progress. The range of the `frame` value passed to the `next_frame` function is defined by the `start` and `end` values. Args: start (float): the first `frame` value for the `next_frame` method end (float): the last `frame` value for the `next_frame` method .. code-block:: python # Create an animation subclass class MyAnimation(Animation): def __init__(self, thing): # Tell the animation to give us values between 0.0 and # 1.0 during the animation Animation.__init__(self, 0.0, 1.0) self._thing = thing def next_frame(self, frame): # Use the `frame` value to set properties self._thing.set_green_value(frame) ''' def __init__(self, start, end): self.start = start self.end = end def do_frame(self, t, duration, easing): ''' This method is called by the animtor class every frame. This method calculated the `frame` value to then call `next_frame`. Args: t (float): the current time elapsed of the animation in seconds duration (float): the length of the animation in seconds easing (int): the easing mode passed to the animator ''' start = self.start change = self.end - self.start if t == duration: # last frame frame = self.end else: if easing == EASE_OUT_EXPO: frame = change * (-pow(2, -10 * t / duration) + 1) + start elif easing == EASE_IN_EXPO: frame = change * pow(2, 10 * (t / duration - 1)) + start self.next_frame(frame) def next_frame(self, frame): ''' This method is called every frame and should be overriden by subclasses. Args: frame (float): a value between `start` and `end` representing the current progress in the animation ''' pass