我试图将图像从右侧移动到中心,我不确定这是否是最佳方式.
var imgTag = null;
var x = 0;
var y = 0;
var id;
function doCanvas()
{
var canvas = document.getElementById('icanvas');
var ctx = canvas.getContext("2d");
var imgBkg = document.getElementById('imgBkg');
imgTag = document.getElementById('imgTag');
ctx.drawImage(imgBkg,0);
x = canvas.width;
y = 40;
id = setInterval(moveImg,0.25);
}
function moveImg()
{
if(x <= 250)
clearInterval(id);
var canvas = document.getElementById('icanvas');
var ctx = canvas.getContext("2d");
ctx.clearRect(0,canvas.width,canvas.height);
var imgBkg = document.getElementById('imgBkg');
ctx.drawImage(imgBkg,0);
ctx.drawImage(imgTag,x,y);
x = x - 1;
}
任何建议？
解决方法
这个问题是5年之久,但由于我们现在有了requestAnimationFrame,这里有一个使用vanilla JavaScript的方法：
var imgTag = new Image();
var canvas = document.getElementById('icanvas');
var ctx = canvas.getContext("2d");
var x = canvas.width;
var y = 0;
imgTag.onload = animate;
imgTag.src = "http://i.stack.imgur.com/Rk0DW.png"; // load image
function animate() {
ctx.clearRect(0,canvas.height); // clear canvas
ctx.drawImage(imgTag,y); // draw image at current position
x -= 4;
if (x > 250) requestAnimationFrame(animate) // loop
}
<canvas id="icanvas" width=640 height=180></canvas>