firefox-main/testing/web-platform/tests/webcodecs/videoFrame-drawImage-rgbx.any.js (file symbol)

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// META: global=window,dedicatedworker
// Expected opaque colors, one per pixel of a 4x2 picture.
const kColors = [
[255, 0, 0],
[0, 255, 0],
[0, 0, 255],
[255, 255, 255],
[0, 0, 0],
[10, 200, 90],
[200, 100, 30],
[128, 64, 192],
];
const kWidth = 4;
const kHeight = 2;
function makeData(format, fourthByte) {
const data = new Uint8Array(kWidth * kHeight * 4);
kColors.forEach(([r, g, b], i) => {
const swapped = format.startsWith('BGR');
data[4 * i + 0] = swapped ? b : r;
data[4 * i + 1] = g;
data[4 * i + 2] = swapped ? r : b;
data[4 * i + 3] = fourthByte;
});
return data;
}
function drawAndVerify(frame, description) {
const canvas = new OffscreenCanvas(kWidth, kHeight);
const ctx = canvas.getContext('2d');
ctx.drawImage(frame, 0, 0);
const pixels = ctx.getImageData(0, 0, kWidth, kHeight).data;
kColors.forEach(([r, g, b], i) => {
const actual = Array.from(pixels.subarray(4 * i, 4 * i + 4));
assert_array_equals(
actual, [r, g, b, 255],
`${description}: pixel ${i} (x=${i % kWidth}, y=${Math.floor(i / kWidth)})`);
});
}
function makeFrame(format, fourthByte) {
return new VideoFrame(makeData(format, fourthByte), {
format: format,
codedWidth: kWidth,
codedHeight: kHeight,
timestamp: 0,
});
}
// The fourth byte of an RGBX/BGRX pixel is not alpha: whatever its value, the drawn pixels must be opaque and carry the right RGB values.
for (const format of ['RGBX', 'BGRX']) {
for (const padding of [0x00, 0x7f, 0xff]) {
promise_test(async t => {
const frame = makeFrame(format, padding);
t.add_cleanup(() => frame.close());
assert_equals(frame.format, format);
drawAndVerify(frame, `${format}, padding 0x${padding.toString(16)}`);
}, `Drawing a ${format} VideoFrame with padding byte ${padding} to a canvas gives opaque correct RGB`);
}
}
promise_test(async t => {
const rgbx = makeFrame('RGBX', 0x00);
const bgrx = makeFrame('BGRX', 0x00);
t.add_cleanup(() => { rgbx.close(); bgrx.close(); });
const readPixels = frame => {
const ctx = new OffscreenCanvas(kWidth, kHeight).getContext('2d');
ctx.drawImage(frame, 0, 0);
return ctx.getImageData(0, 0, kWidth, kHeight).data;
};
assert_array_equals(readPixels(rgbx), readPixels(bgrx));
}, 'RGBX and BGRX VideoFrames with the same colors draw the same pixels');