|  | <!DOCTYPE html> | 
|  | <meta charset="utf-8"> | 
|  | <title>Canvas's ImageBitmapRenderingContext test</title> | 
|  | <script src="/resources/testharness.js"></script> | 
|  | <script src="/resources/testharnessreport.js"></script> | 
|  | <link rel="help" href="https://html.spec.whatwg.org/multipage/scripting.html#the-imagebitmap-rendering-context"> | 
|  | <script> | 
|  | var width = 10; | 
|  | var height = 10; | 
|  |  | 
|  | function testCanvas(bitmapCanvas, r, g, b, a) | 
|  | { | 
|  | var myCanvas = document.createElement('canvas'); | 
|  | myCanvas.width = width; | 
|  | myCanvas.height = height; | 
|  | var myCtx = myCanvas.getContext('2d'); | 
|  | myCtx.drawImage(bitmapCanvas, 0, 0); | 
|  | var color = myCtx.getImageData(5, 5, 1, 1).data; | 
|  | assert_array_equals(color, [r, g, b, a]); | 
|  | } | 
|  |  | 
|  | promise_test(function() { | 
|  | function testTransferFromImageBitmapNullability(greenImage) { | 
|  | var bitmapCanvas = new OffscreenCanvas(width,height); | 
|  | var bitmapCtx = bitmapCanvas.getContext('bitmaprenderer'); | 
|  | bitmapCtx.transferFromImageBitmap(greenImage); | 
|  |  | 
|  | // Make sure the bitmap renderer canvas is filled correctly. | 
|  | var myCanvas = document.createElement('canvas'); | 
|  | var myCtx = myCanvas.getContext('bitmaprenderer'); | 
|  | myCtx.transferFromImageBitmap(bitmapCanvas.transferToImageBitmap()); | 
|  | testCanvas(myCanvas, 0, 255, 0, 255); | 
|  |  | 
|  | // Test that after transfering for second time to ImageBitmap produces | 
|  | // a black bitmap of the same size | 
|  | var myCanvas2 = document.createElement('canvas'); | 
|  | var myCtx2 = myCanvas2.getContext('bitmaprenderer'); | 
|  | myCtx2.transferFromImageBitmap(bitmapCanvas.transferToImageBitmap()); | 
|  | testCanvas(myCanvas2, 0, 0, 0, 0); | 
|  | } | 
|  |  | 
|  | var greenCanvas = document.createElement('canvas'); | 
|  | greenCanvas.width = width; | 
|  | greenCanvas.height = height; | 
|  | var greenCtx = greenCanvas.getContext('2d'); | 
|  | greenCtx.fillStyle = '#0f0'; | 
|  | greenCtx.fillRect(0, 0, width, height); | 
|  |  | 
|  | return Promise.all([ | 
|  | createImageBitmap(greenCanvas), | 
|  | ]).then(([greenImage]) => { | 
|  | testTransferFromImageBitmapNullability(greenImage); | 
|  | }); | 
|  | },'Test that transferToImageBitmap works and that resets the imagebitmap to black'); | 
|  |  | 
|  | </script> |