canvas-createImageBitmap-resize.html

Enable keyboard shortcuts

This test has a WPT meta file that expects 6 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /html/canvas/element/manual/imagebitmap/canvas-createImageBitmap-resize.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script>

function checkNoCrop(imageBitmap)

    var canvas = document.createElement("canvas");

    canvas.width = 50;

    canvas.height = 50;

    var ctx = canvas.getContext("2d");

    ctx.clearRect(0, 0, canvas.width, canvas.height);

    ctx.drawImage(imageBitmap, 0, 0);

    var d = ctx.getImageData(0, 0, 1, 1).data;

    assert_array_equals(d, [255, 0, 0, 255], "This pixel should be red.");

    d = ctx.getImageData(39, 0, 1, 1).data;

    assert_array_equals(d, [0, 255, 0, 255], "This pixel should be green.");

    d = ctx.getImageData(0, 39, 1, 1).data;

    assert_array_equals(d, [0, 0, 255, 255], "This pixel should be blue.");

    d = ctx.getImageData(39, 39, 1, 1).data;

    assert_array_equals(d, [0, 0, 0, 255], "This pixel should be black.");

    d = ctx.getImageData(41, 41, 1, 1).data;

    assert_array_equals(d, [0, 0, 0, 0], "This pixel should be transparent black.");

function checkCrop(imageBitmap)

    var canvas = document.createElement("canvas");

    canvas.width = 50;

    canvas.height = 50;

    var ctx = canvas.getContext("2d");

    ctx.clearRect(0, 0, canvas.width, canvas.height);

    ctx.drawImage(imageBitmap, 0, 0);

    var d = ctx.getImageData(0, 0, 1, 1).data;

    assert_array_equals(d, [255, 0, 0, 255], "This pixel should be red.");

    d = ctx.getImageData(19, 0, 1, 1).data;

    assert_array_equals(d, [0, 255, 0, 255], "This pixel should be green.");

    d = ctx.getImageData(0, 19, 1, 1).data;

    assert_array_equals(d, [0, 0, 255, 255], "This pixel should be blue.");

    d = ctx.getImageData(19, 19, 1, 1).data;

    assert_array_equals(d, [0, 0, 0, 255], "This pixel should be black.");

    d = ctx.getImageData(21, 21, 1, 1).data;

    assert_array_equals(d, [0, 0, 0, 0], "This pixel should be transparent black.");

function compareBitmaps(bitmap1, bitmap2)

    var canvas1 = document.createElement("canvas");

    var canvas2 = document.createElement("canvas");

    canvas1.width = 50;

    canvas1.height = 50;

    canvas2.width = 50;

    canvas2.height = 50;

    var ctx1 = canvas1.getContext("2d");

    var ctx2 = canvas2.getContext("2d");

    ctx1.clearRect(0, 0, canvas1.width, canvas1.height);

    ctx2.clearRect(0, 0, canvas2.width, canvas2.height);

    ctx1.drawImage(bitmap1, 0, 0);

    ctx2.drawImage(bitmap2, 0, 0);

    var data1 = ctx1.getImageData(0, 0, 50, 50).data;

    var data2 = ctx2.getImageData(0, 0, 50, 50).data;

    var dataMatched = true;

    for (var i = 0; i < data1.length; i++) {

        if (data1[i] != data2[i]) {

            dataMatched = false;

            break;

    assert_false(dataMatched);

function testImageBitmap(source)

    return Promise.all([

        createImageBitmap(source, {resizeWidth: 40, resizeHeight: 40, resizeQuality: "high"}),

        createImageBitmap(source, {resizeWidth: 40, resizeHeight: 40, resizeQuality: "medium"}),

        createImageBitmap(source, {resizeWidth: 40, resizeHeight: 40, resizeQuality: "low"}),

        createImageBitmap(source, {resizeWidth: 40, resizeHeight: 40, resizeQuality: "pixelated"}),

        createImageBitmap(source, 5, 5, 10, 10, {resizeWidth: 20, resizeHeight: 20, resizeQuality: "high"}),

        createImageBitmap(source, 5, 5, 10, 10, {resizeWidth: 20, resizeHeight: 20, resizeQuality: "medium"}),

        createImageBitmap(source, 5, 5, 10, 10, {resizeWidth: 20, resizeHeight: 20, resizeQuality: "low"}),

        createImageBitmap(source, 5, 5, 10, 10, {resizeWidth: 20, resizeHeight: 20, resizeQuality: "pixelated"}),

    ]).then(([noCropHigh, noCropMedium, noCropLow, noCropPixelated, cropHigh, cropMedium, cropLow, cropPixelated]) => {

        checkNoCrop(noCropHigh);

        checkNoCrop(noCropMedium);

        checkNoCrop(noCropLow);

        checkNoCrop(noCropPixelated);

        checkCrop(cropHigh);

        checkCrop(cropMedium);

        checkCrop(cropLow);

        checkCrop(cropPixelated);

        // Brute-force comparison among all bitmaps is too expensive

        compareBitmaps(noCropHigh, noCropMedium);

        compareBitmaps(noCropLow, noCropPixelated);

        compareBitmaps(cropHigh, cropMedium);

        compareBitmaps(cropLow, cropPixelated);

});

function initializeTestCanvas()

    var testCanvas = document.createElement("canvas");

    testCanvas.width = 20;

    testCanvas.height = 20;

    var testCtx = testCanvas.getContext("2d");

    testCtx.fillStyle = "rgb(255, 0, 0)";

    testCtx.fillRect(0, 0, 10, 10);

    testCtx.fillStyle = "rgb(0, 255, 0)";

    testCtx.fillRect(10, 0, 10, 10);

    testCtx.fillStyle = "rgb(0, 0, 255)";

    testCtx.fillRect(0, 10, 10, 10);

    testCtx.fillStyle = "rgb(0, 0, 0)";

    testCtx.fillRect(10, 10, 10, 10);

    return testCanvas;

// Blob

promise_test(function() {

    return new Promise((resolve, reject) => {

        var xhr = new XMLHttpRequest();

        xhr.open("GET", '/images/pattern.png');

        xhr.responseType = 'blob';

        xhr.send();

        xhr.onload = function() {

            resolve(xhr.response);

};

    }).then(testImageBitmap);

}, 'createImageBitmap from a Blob with resize option.');

// HTMLCanvasElement

promise_test(function() {

    var testCanvas = initializeTestCanvas();

    return testImageBitmap(testCanvas);

}, 'createImageBitmap from a HTMLCanvasElement with resize option.');

// HTMLImageElement

promise_test(function() {

    return new Promise((resolve, reject) => {

        var image = new Image();

        image.onload = function() {

            resolve(image);

        image.src = '/images/pattern.png'

    }).then(testImageBitmap);

}, 'createImageBitmap from a HTMLImageElement with resize option.');

// HTMLImageElement of svg with no specified size

promise_test(function() {

    return new Promise((resolve, reject) => {

        var image = new Image();

        image.onload = function() {

            resolve(image);

        image.src = '/images/pattern-nosize.svg'

    }).then(testImageBitmap);

}, 'createImageBitmap from a HTMLImageElement of svg with no specified size with resize option.');

// ImageBitmap

promise_test(function() {

    var testCanvas = initializeTestCanvas();

    return createImageBitmap(testCanvas).then(testImageBitmap);

}, 'createImageBitmap from an ImageBitmap with resize option.');

// ImageData

promise_test(function() {

    var canvas = initializeTestCanvas();

    var ctx = canvas.getContext("2d");

    var data = ctx.getImageData(0, 0, 20, 20);

    return testImageBitmap(data);

}, 'createImageBitmap from an ImageData with resize option.');

</script>