通过Canvas实现的可刮涂层效果.
修改img.src时涂层也会自动适应新图片的尺寸.
修改layer函数可更改涂层样式.
涂层:
可刮效果:
<!DOCTYPE html>
<html>
<body>
<img src="images/2.jpg" id="lamp" width="100%" />
<canvas/>
<script>
(function(bodyStyle) {
bodyStyle.mozUserSelect = ‘none‘;
bodyStyle.webkitUserSelect = ‘none‘;
var img = new Image();
var canvas = document.querySelector(‘canvas‘);
canvas.style.backgroundColor=‘transparent‘;
canvas.style.position = ‘absolute‘;
img.addEventListener(‘load‘, function(e) {
var ctx;
var w = img.width,
h = img.height;
var offsetX = canvas.offsetLeft,
offsetY = canvas.offsetTop;
var mousedown = false;
function layer(ctx) {
//ctx.fillStyle = ‘red‘;
//ctx.fillRect(0, 0, w, h);//颜色图层
var img=document.getElementById("lamp")
var pat=ctx.createPattern(img,‘repeat‘);
ctx.rect(0,0,w,h);
ctx.fillStyle=pat;
ctx.fill();
}
function eventDown(e){
e.preventDefault();
mousedown=true;
}
function eventUp(e){
e.preventDefault();
mousedown=false;
}
function eventMove(e){
e.preventDefault();
if(mousedown) {
if(e.changedTouches){
e=e.changedTouches[e.changedTouches.length-1];
}
var x = (e.clientX + document.body.scrollLeft || e.pageX) - offsetX || 0,
y = (e.clientY + document.body.scrollTop || e.pageY) - offsetY || 0;
with(ctx) {
beginPath()
arc(x, y, 10, 0, Math.PI * 2);
fill();
}
}
}
canvas.width=w;
canvas.height=h;
canvas.style.backgroundImage=‘url(‘+img.src+‘)‘;
ctx=canvas.getContext(‘2d‘);
ctx.fillStyle=‘transparent‘;
ctx.fillRect(0, 0, w, h);
layer(ctx);
ctx.globalCompositeOperation = ‘destination-out‘;
canvas.addEventListener(‘touchstart‘, eventDown);
canvas.addEventListener(‘touchend‘, eventUp);
canvas.addEventListener(‘touchmove‘, eventMove);
canvas.addEventListener(‘mousedown‘, eventDown);
canvas.addEventListener(‘mouseup‘, eventUp);
canvas.addEventListener(‘mousemove‘, eventMove);
});
img.src = ‘images/1.jpg‘;//被遮住的背景图
})(document.body.style);
</script>
</body>
</html>
时间： 2024-10-11 18:15:37