| <!DOCTYPE html> |
| <html> |
| <body> |
| <canvas id='output' width='150' height='150'></canvas> |
| <script id='myWorker' type='text/worker'> |
| self.onmessage = function(e) { |
| var aCanvas = new OffscreenCanvas(150, 150); |
| var ctx = aCanvas.getContext('2d'); |
| |
| ctx.drawImage(e.data, 0, 0); |
| ctx.drawImage(e.data, 30, 30, 30, 30); |
| // stretch the image |
| ctx.drawImage(e.data, 8, 8, 15, 15, 60, 60, 60, 60); |
| // reduce the image |
| ctx.drawImage(e.data, 8, 8, 15, 15, 120, 120, 15, 15); |
| |
| var image = aCanvas.transferToImageBitmap(); |
| self.postMessage(image, [image]); |
| }; |
| </script> |
| <script> |
| if (window.testRunner) { |
| testRunner.waitUntilDone(); |
| } |
| |
| var patternCanvas = document.createElement('canvas'); |
| patternCanvas.width = 30; |
| patternCanvas.height = 30; |
| var patternCtx = patternCanvas.getContext('2d'); |
| patternCtx.fillStyle = '#f00'; |
| patternCtx.fillRect(0, 0, 15, 15); |
| patternCtx.fillStyle = '#0f0'; |
| patternCtx.fillRect(15, 0, 15, 15); |
| patternCtx.fillStyle = '#00f'; |
| patternCtx.fillRect(0, 15, 15, 15); |
| patternCtx.fillStyle = "#ff0"; |
| patternCtx.fillRect(15, 15, 15, 15); |
| createImageBitmap(patternCanvas).then(consumeImageBitmap); |
| |
| function consumeImageBitmap(patternImage) { |
| var blob = new Blob([document.getElementById('myWorker').textContent]); |
| var worker = new Worker(URL.createObjectURL(blob)); |
| worker.addEventListener('message', msg => { |
| var outputCtx = document.getElementById('output').getContext('bitmaprenderer'); |
| outputCtx.transferFromImageBitmap(msg.data); |
| if (window.testRunner) { |
| testRunner.notifyDone(); |
| } |
| }); |
| worker.postMessage(patternImage, [patternImage]); |
| } |
| </script> |
| </body> |
| |