<canvas id="mycanvas1" width="270" height="270"></canvas>
<script type="text/javascript">
var ctx = document.getElementById("mycanvas1").getContext('2d');
var img = new Image();
img.onload = function(){
for(var i = 0; i < 4;i++){
ctx.drawImage(img,0,270*i,270,270,0,0,270,270);
}
}
img.src = 'themes/img/1.png';
</script>
这里是代码。。我想每一帧就修改i的值。就可以换图。但是for循环里面一下就循环到最后了 没有体现出来过程。我把
ctx.drawImage(img,0,270*i,270,270,0,0,270,270); 封装成一个函数。利用setInterval 去调用 还是不行。。
求哪位帮我改下
素材我也贴上来
ctx.drawImage(img,0,270*i,270,270,0,0,270,270); 这个代码执行完后调用时间倒计时的方法,就实现了你要的效果了
<script>
window.onload = function(){
var value = [1,2,3,4];
var index = 0;
var timer = setInterval(change, 1000);
function change(){
if (index >= value.length) {
clearInterval(timer);
return;
}
var div = document.getElementById("d");
div.innerHTML = value[index].toString();
index++;
}
}
</script>
<body>
<div id="d"></div>
</body>
</html>
ctx.drawImage(img,0,270*i,270,270,0,0,270,270);
}var me = this;
for(var i = 0; i < 4;i++){
(function(i){
ctx.drawImage(me , 270*i );
})(i)
}
<script type="text/javascript">
var ctx = document.getElementById("mycanvas1").getContext('2d');
var img = new Image();
var i=0,t;
img.onload = function(){t=setInterval("theforever_csdn()",1000); };
img.style.position="absolute";
img.style.top="-1000px";
document.body.appendChild(img).src = 'http://avatar.profile.csdn.net/A/9/7/2_theforever.jpg';
function theforever_csdn(){
ctx.clearRect(0, 0, 500, 500);
ctx.drawImage(img,0,0,120,120,i*100,0,120,120);
i++;if(i==3) clearInterval(t);
}
</script>
ctx.drawImage(img,0,270*i,270,270,0,0,270,270);
}
==》
drawImage(img,i);function drawImage(img,index)
{
ctx.drawImage(img,0,270*index,270,270,0,0,270,270);
index++;
if(index < 4){
setTimeout(function(){drawImage(img,index);});
}
}