2016-05-01 22:59:41 -07:00

57 lines
1.7 KiB
TypeScript

import {Injectable} from '@angular/core';
import {Math} from '../../src/facade/math';
import {getDOM} from '../dom/dom_adapter';
@Injectable()
export class BrowserDetails {
elapsedTimeIncludesDelay = false;
constructor() { this.doesElapsedTimeIncludesDelay(); }
/**
* Determines if `event.elapsedTime` includes transition delay in the current browser. At this
* time, Chrome and Opera seem to be the only browsers that include this.
*/
doesElapsedTimeIncludesDelay(): void {
var div = getDOM().createElement('div');
getDOM().setAttribute(div, 'style',
`position: absolute; top: -9999px; left: -9999px; width: 1px;
height: 1px; transition: all 1ms linear 1ms;`);
// Firefox requires that we wait for 2 frames for some reason
this.raf((timestamp: any) => {
getDOM().on(div, 'transitionend', (event: any) => {
var elapsed = Math.round(event.elapsedTime * 1000);
this.elapsedTimeIncludesDelay = elapsed == 2;
getDOM().remove(div);
});
getDOM().setStyle(div, 'width', '2px');
}, 2);
}
raf(callback: Function, frames: number = 1): Function {
var queue: RafQueue = new RafQueue(callback, frames);
return () => queue.cancel();
}
}
class RafQueue {
currentFrameId: number;
constructor(public callback: Function, public frames: number) { this._raf(); }
private _raf() {
this.currentFrameId =
getDOM().requestAnimationFrame((timestamp: number) => this._nextFrame(timestamp));
}
private _nextFrame(timestamp: number) {
this.frames--;
if (this.frames > 0) {
this._raf();
} else {
this.callback(timestamp);
}
}
cancel() {
getDOM().cancelAnimationFrame(this.currentFrameId);
this.currentFrameId = null;
}
}