我正在画画布罪,并为其增加运动感
export class CanvasComponent implements OnInit {
@ViewChild('canvas', { static: true })
canvas: ElementRef<HTMLCanvasElement>;
ctx: CanvasRenderingContext2D;
winddrawvalue = 0;
windvalue = 0;
constructor() { }
@Input() set speeddata(speed: number){
this.windvalue = speed;
this.drawWind();
}
ngOnInit(): void {
this.ctx = this.canvas.nativeElement.getContext('2d');
}
drawWind() {
requestAnimationFrame(this.drawWind.bind(this));
const canvas = this.canvas.nativeElement;
this.ctx.lineWidth = 2;
this.ctx.clearRect(0, 0, canvas.width, canvas.height);
this.ctx.beginPath();
this.ctx.moveTo(-10, canvas.height / 2 - 12);
for (let i = 0; i < canvas.width; i++) {
this.ctx.lineTo(i, canvas.height / 2 - 12 + Math.sin(i * 0.04 + this.winddrawvalue) * 15);
}
this.ctx.moveTo(-10, canvas.height / 2);
for (let i = 0; i < canvas.width; i++) {
this.ctx.lineTo(i, canvas.height / 2 + Math.sin(i * 0.04 + this.winddrawvalue) * 15);
}
this.ctx.moveTo(-10, canvas.height / 2 + 12);
for (let i = 0; i < canvas.width; i++) {
this.ctx.lineTo(i, canvas.height / 2 + 12 + Math.sin(i * 0.04 + this.winddrawvalue) * 15);
}
this.ctx.stroke();
this.winddrawvalue += this.windvalue;
}
}
并且每次我按下按钮以再次绘制它时,画布都会重新绘制它,但是它的运动速度比以前快了2倍。我试图做
request = requestAnimationFrame(this.drawWind.bind(this));
@Input() set speeddata(speed: number){
this.windvalue = speed;
this.stopAnimation(this.request);
this.drawWind();
}
stopAnimation(req) {
cancelAnimationFrame(req);
}
[cancelAnimationFrame()
希望它将获得requestID来停止正在进行的动画,但是它不起作用。
由于drawWind
每次都会设置下一个调用,所以当您从点击处理程序调用它时,现在有两个并行运行的序列,并且运行速度快了两倍。
您说您尝试过cancelAnimationFrame
,但没有向我们显示该代码。实际上,这就是您将如何处理:
drawWind() {
cancelAnimationFrame(this.rafHandle);
this.rafHandle = requestAnimationFrame(this.drawWind.bind(this));
现在,当按钮单击已计划了drawWind
回调时调用rAF
时,它将取消该回调并设置一个新的回调。因此,您仍然只能运行一个系列。