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<!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(ctx, r, g, b, a)
{
var color = ctx.getImageData(5, 5, 1, 1).data;
assert_array_equals(color, [r, g, b, a]);
}
promise_test(function() {
function transferFromImageBitmapToBlobOffscreen(greenImage) {
var bitmapCanvas = new OffscreenCanvas(width,height);
var bitmapCtx = bitmapCanvas.getContext('bitmaprenderer');
bitmapCtx.transferFromImageBitmap(greenImage);
return bitmapCanvas.convertToBlob();
}
function drawBlobToCanvas(blob) {
// Make sure the bitmap renderer canvas is filled correctly.
var pngImage = new Image();
var myCanvasToTest = document.createElement('canvas');
myCanvasToTest.width = width;
myCanvasToTest.height = height;
// Wait for the blob img to load.
return new Promise(function(resolve) {
pngImage.src = URL.createObjectURL(blob);
pngImage.onload = function() {
var myCtxToTest = myCanvasToTest.getContext('2d');
myCtxToTest.drawImage(pngImage, 0, 0);
resolve(myCtxToTest);
};
});
}
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 createImageBitmap(greenCanvas).then(
greenImage => transferFromImageBitmapToBlobOffscreen(greenImage)
).then(
blob => drawBlobToCanvas(blob)
).then(
ctx => testCanvas(ctx, 0, 255, 0, 255)
);
},'Test that convertToBlob works and produce the expected image');
</script>
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