LayoutTests/fast/canvas/canvas-resize-after-paint-without-layout.html - WebKit - Git at Google

 <!DOCTYPE html>
 <!-- Check that resizing a (potentially accelerated) canvas properly clears its
      contents even if the layout size of the canvas does not change. Expected
      output is a blank canvas.
      https://bugs.webkit.org/show_bug.cgi?id=80871 -->
 <html>
   <head>
     <style>
       #canvas {
         outline: solid 1px black;
         width: 300px;
         height: 300px;
       }
     </style>
     <script src="resources/repaint.js"></script>
     <script>
       if (window.testRunner)
         testRunner.dumpAsText(true);

       function runTest() {
         var canvas = document.getElementById('canvas');
         var ctx = canvas.getContext('2d');
         ctx.fillStyle = 'red';
         ctx.fillRect(0, 0, 300, 300);
         runRepaintTest();
       }

       function repaintTest() {
         var canvas = document.getElementById('canvas');
         // This changes the resolution of the canvas but keeps its layout size constant.
         canvas.width = canvas.width / 2;
       }
     </script>
   </head>
   <body onload="runTest();">
     <canvas id="canvas" width="300" height="300"/>
   </body>
 </html>
	<!DOCTYPE html>
	<!-- Check that resizing a (potentially accelerated) canvas properly clears its
	contents even if the layout size of the canvas does not change. Expected
	output is a blank canvas.
	https://bugs.webkit.org/show_bug.cgi?id=80871 -->
	<html>
	<head>
	<style>
	#canvas {
	outline: solid 1px black;
	width: 300px;
	height: 300px;
	}
	</style>
	<script src="resources/repaint.js"></script>
	<script>
	if (window.testRunner)
	testRunner.dumpAsText(true);

	function runTest() {
	var canvas = document.getElementById('canvas');
	var ctx = canvas.getContext('2d');
	ctx.fillStyle = 'red';
	ctx.fillRect(0, 0, 300, 300);
	runRepaintTest();
	}

	function repaintTest() {
	var canvas = document.getElementById('canvas');
	// This changes the resolution of the canvas but keeps its layout size constant.
	canvas.width = canvas.width / 2;
	}
	</script>
	</head>
	<body onload="runTest();">
	<canvas id="canvas" width="300" height="300"/>
	</body>
	</html>