Evaluating java script expression inside function argument
I am trying to define a scale variable (s), where the image scales dynamically according to its value. I don't think the expression s*100 is evaluating as there is no difference in size. What is wrong.
<html>
<body onload="draw();">
<canvas id="canvas" width="150" height="150"></canvas>
</body>
<script type="application/javascript">
function draw() {
var canvas = document.getElementById("canvas");
if (canvas.getContext) {
var ctx = canvas.getContext("2d");
var s = 10000;
ctx.fillStyle = "rgba(0, 0, 200开发者_JAVA技巧, 0.1)";
ctx.fillRect (0, 0, s*100, s*100);
}
}
</script>
</html>
The reason you don't see any change is because you are trying to render a gigantic rectangle onto a 150x150 canvas, so the part outside the canvas is ignored. Make your canvas really big and you'll see it working. Here's a working example, it keeps rendering the same square by increasing the scale each time. http://jsfiddle.net/3ZAex/2/
Figured it out.. it was because my canvas was too small.. width="150" height="150"
加载中,请稍侯......
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