Hel*_*rld 9 javascript html5 canvas html5-canvas
为什么我的多个矩形不会画在画布上？
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script src="Scripts/jquery-1.9.1.min.js"></script>
</head>
<body>
<canvas id="myCanvas" width="500" height="500" style="border:1px solid red">
<p>Your browser doesn't support canvas.</p>
</canvas>
</body>
</html>
<script type ="text/javascript">
function Shape(x, y, w, h, fill) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.fill = fill;
}
// get canvas element.
var elem = document.getElementById('myCanvas');
// check if context exist
if (elem.getContext) {
var myRect = [];
myRect.push(new Shape(10, 0, 25, 25, "#333"))
myRect.push(new Shape(0, 40, 39, 25, "#333"))
myRect.push(new Shape(0, 80, 100, 25, "#333"))
context = elem.getContext('2d');
for (i in myRect) {
//console.log(x);
context.fillRect(i.x, i.y, i.w, i.h)
}
//// x, y, width, height
//context.fillRect(0, 0, 50, 50);
//// x, y, width, height
//context.fillRect(75, 0, 50, 50);
}
</script>
感谢帮助.
Raa*_*aad 15
好的,所以你几乎就在那里.迭代遍历矩形数组时,您将遍历数组键而不是对象本身(请参阅如何使用对象作为成员循环通过纯JavaScript对象？).另外,正如@ jimjimmy1995指出的那样,你需要使用.fillStyleas 设置填充.fillRect没有填充参数.
此代码将起作用:
function Shape(x, y, w, h, fill) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.fill = fill;
}
// get canvas element.
var elem = document.getElementById('myCanvas');
// check if context exist
if (elem.getContext) {
var myRect = [];
myRect.push(new Shape(10, 0, 25, 25, "#333"));
myRect.push(new Shape(0, 40, 39, 25, "#333"));
myRect.push(new Shape(0, 80, 100, 25, "#333"));
context = elem.getContext('2d');
for (var i in myRect) {
oRec = myRect[i];
context.fillStyle = oRec.fill;
context.fillRect(oRec.x, oRec.y, oRec.w, oRec.h);
}
}