| <!DOCTYPE html> |
| <title>Test using a placeholder canvas as an image source.</title> |
| <head> |
| <title>Test if the users can change Image Rendering Quality in Offscreen Canvas</title> |
| <style type="text/css"> |
| #can { |
| width: 500px; |
| height: 500px; |
| image-rendering: pixelated; |
| } |
| </style> |
| </head> |
| |
| <body> |
| <canvas id="can" width="50" height="50"></canvas> |
| |
| <script id='myWorker' type='text/worker'> |
| |
| var ctx_o; |
| self.onmessage = function(msg) { |
| ctx_o = msg.data.getContext('2d'); |
| draw(); |
| }; |
| |
| function draw() { |
| ctx_o.clearRect(0, 0, 50, 50); |
| ctx_o.fillRect(10, 10, 30, 30); |
| const d = ctx_o.getImageData(20, 20, 1, 1); |
| if (d.data[0] == 0 && d.data[3] == 255) { |
| self.postMessage("done"); |
| } else { |
| requestAnimationFrame(draw); |
| } |
| } |
| </script> |
| |
| <script> |
| var canvas = document.getElementById("can"); |
| canvas.width = 50; |
| canvas.height = 50; |
| var offscreen = canvas.transferControlToOffscreen(); |
| |
| var blob = new Blob([document.getElementById('myWorker').textContent]); |
| var worker = new Worker(URL.createObjectURL(blob)); |
| canvas.style.imageRendering = "auto"; |
| worker.postMessage(offscreen, [offscreen]); |
| |
| function waitForCanvasToDraw() { |
| return new Promise(resolve => { |
| var i = 0; |
| const testPixel = function() { |
| canvas.toBlob(blob => { |
| createImageBitmap(blob).then(image => { |
| if (verifyImage(image, "verify if image is drawn on offscreencanvas.")) { |
| setTimeout(resolve, 2000); |
| } else { |
| requestAnimationFrame(testPixel); |
| } |
| }) |
| }); |
| } |
| testPixel(); |
| }) |
| } |
| |
| function verifyImage(image, description) { |
| var testCanvas = document.createElement('canvas'); |
| var testCtx = testCanvas.getContext('2d'); |
| testCtx.drawImage(image, 0, 0); |
| const d = testCtx.getImageData(20, 20, 1, 1); |
| return (d.data[0] == 0 && d.data[3] == 255); |
| } |
| |
| if (window.testRunner) { |
| testRunner.waitUntilDone(); |
| } |
| |
| waitForCanvasToDraw().then(() => { |
| if (window.testRunner) { |
| testRunner.notifyDone(); |
| } |
| }).catch(err => { |
| testRunner.notifyDone(); |
| throw err; |
| }); |
| |
| </script> |
| |
| </body> |
