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Html5系列(十四) canvas 奇怪的形状水平渐变

2015-04-16 23:13 381 查看
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>填充渐变形状</title>
<script src="js/modernizr.js"></script>
</head>

<body>
<script type="text/javascript">
window.addEventListener('load',eventWindowLoaded,false);
function eventWindowLoaded(){
canvasApp();
}
function canvasSupport(){
return Modernizr.canvas;
}
function canvasApp(){
if(!canvasSupport()){
return;
}else{
var theCanvas = document.getElementById('canvas')
var context = theCanvas.getContext("2d")

}
drawScreen();
function drawScreen(){
//水平渐变值必须保持为0
var gr = context.createLinearGradient(0,0,100,0);
//添加颜色端点
gr.addColorStop(0,'rgb(255,0,0)');
gr.addColorStop(.5,'rgb(0,255,0)');
gr.addColorStop(1,'rgb(0,0,255)');
//应用fillStyle生成渐变
context.fillStyle = gr;
context.beginPath();
context.moveTo(0,0);
context.lineTo(50,0);
context.lineTo(100,50);
context.lineTo(50,100);
context.lineTo(0,100);
//将水平渐变应用到复杂形状
context.lineTo(0,0);
context.stroke();
context.fill();
//context.fill();将当前的fillStyle填充到形状中
context.closePath();

}
}
$(document).ready(function(e) {

});

</script>
<canvas id="canvas" width="500" height="500">
你的浏览器无法使用canvas
小白童鞋;你的支持是我最大的快乐!!
</canvas>
</body>
</html>


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