mirror of https://github.com/perkeep/perkeep.git
90 lines
2.3 KiB
JavaScript
90 lines
2.3 KiB
JavaScript
/*
|
|
Copyright 2013 The Camlistore Authors
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
goog.provide('cam.AnimationLoop');
|
|
|
|
goog.require('goog.events.EventTarget');
|
|
|
|
// Provides an easier-to-use interface around window.requestAnimationFrame(), and abstracts away browser differences.
|
|
// @param {Window} win
|
|
cam.AnimationLoop = function(win) {
|
|
goog.base(this);
|
|
|
|
this.win_ = win;
|
|
|
|
this.requestAnimationFrame_ = win.requestAnimationFrame || win.mozRequestAnimationFrame || win.webkitRequestAnimationFrame || win.msRequestAnimationFrame;
|
|
|
|
this.handleFrame_ = this.handleFrame_.bind(this);
|
|
|
|
this.lastTimestamp_ = 0;
|
|
|
|
if (this.requestAnimationFrame_) {
|
|
this.requestAnimationFrame_ = this.requestAnimationFrame_.bind(win);
|
|
} else {
|
|
this.requestAnimationFrame_ = this.simulateAnimationFrame_.bind(this);
|
|
}
|
|
};
|
|
|
|
goog.inherits(cam.AnimationLoop, goog.events.EventTarget);
|
|
|
|
cam.AnimationLoop.FRAME_EVENT_TYPE = 'frame';
|
|
|
|
cam.AnimationLoop.prototype.isRunning = function() {
|
|
return Boolean(this.lastTimestamp_);
|
|
};
|
|
|
|
cam.AnimationLoop.prototype.start = function() {
|
|
if (this.isRunning()) {
|
|
return;
|
|
}
|
|
|
|
this.lastTimestamp_ = -1;
|
|
this.schedule_();
|
|
};
|
|
|
|
cam.AnimationLoop.prototype.stop = function() {
|
|
this.lastTimestamp_ = 0;
|
|
};
|
|
|
|
cam.AnimationLoop.prototype.schedule_ = function() {
|
|
this.requestAnimationFrame_(this.handleFrame_);
|
|
};
|
|
|
|
cam.AnimationLoop.prototype.handleFrame_ = function(opt_timestamp) {
|
|
if (this.lastTimestamp_ == 0) {
|
|
return;
|
|
}
|
|
|
|
var timestamp = opt_timestamp || new Date().getTime();
|
|
if (this.lastTimestamp_ == -1) {
|
|
this.lastTimestamp_ = timestamp;
|
|
} else {
|
|
this.dispatchEvent({
|
|
type: this.constructor.FRAME_EVENT_TYPE,
|
|
delay: timestamp - this.lastTimestamp_
|
|
});
|
|
this.lastTimestamp_ = timestamp;
|
|
}
|
|
|
|
this.schedule_();
|
|
};
|
|
|
|
cam.AnimationLoop.prototype.simulateAnimationFrame_ = function(fn) {
|
|
this.win_.setTimeout(function() {
|
|
fn(new Date().getTime());
|
|
}, 0);
|
|
};
|