chromium/third_party/blink/web_tests/fast/canvas/canvas-drawImage-shadow.html

<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<body>
<script>
// Create auxiliary canvas to draw to and create an image from.
// This is done instead of simply loading an image from the file system
// because that would throw a SECURITY_ERR DOM Exception.
var aCanvas = document.createElement('canvas');
aCanvas.setAttribute('width', '200');
aCanvas.setAttribute('height', '200');
var aCtx = aCanvas.getContext('2d');

// Draw a circle on the same canvas.
aCtx.beginPath();
aCtx.fillStyle = 'green';
aCtx.arc(100, 100, 150, 0, -Math.PI/2, false);
aCtx.fill();

// Create the image object to be drawn on the master canvas.
var img = new Image();
img.src = aCanvas.toDataURL(); // set a data URI of the base64 enconded image as the source

// Create master canvas.
var canvas = document.createElement('canvas');
document.body.appendChild(canvas);
canvas.setAttribute('width', '600');
canvas.setAttribute('height', '600');
var ctx = canvas.getContext('2d');

var testScenarios = [
    ['Test solid shadow 1', 260, 300, [0, 0, 0, 0]],
    ['Test solid shadow 2', 350, 100, [240, 50, 50, 255]],
    ['Test solid shadow 3', 400, 200, [240, 50, 50, 255]],
    ['Test solid shadow 4', 490, 65, [0, 0, 0, 0]],
    ['Test solid shadow 5', 485, 65, [0, 0, 0, 0]],

    ['Test blurry shadow 1', 260, 400, [0, 0, 0, 0]],
    ['Test blurry shadow 2', 350, 300, [0, 0, 255, 'neq', 255]],
    ['Test blurry shadow 3', 300, 400, [0, 0, 255, 'neq', 255]],
    ['Test blurry shadow 4', 300, 500, [0, 0, 255, 'neq', 255]],
    ['Test blurry shadow 5', 400, 500, [0, 0, 255, 'neq', 255]],
    ['Test blurry shadow 6', 400, 400, [0, 0, 255]],
    ['Test blurry shadow 7', 490, 315, [0, 0, 0, 0]],
    ['Test blurry shadow 8', 485, 320, [0, 0, 0, 0]],   
];

function runTestScenario(x, y, expectedColor)
{
    imageData = ctx.getImageData(x, y, 1, 1).data;
    if (expectedColor.length == 5) {
        assert_array_equals(imageData.slice(0,3), expectedColor.slice(0,3));
        assert_not_equals(imageData[3], expectedColor[4]);
    } else {
        assert_array_equals(imageData.slice(0, expectedColor.length), expectedColor);
    }
}

function drawImageToCanvasAndCheckPixels() {
    ctx.shadowOffsetX = 250;
    ctx.shadowColor = 'rgba(240, 50, 50, 1.0)';
    ctx.drawImage(img, 50, 50);

    ctx.shadowOffsetX = 250;
    ctx.shadowBlur = 6;
    ctx.shadowColor = 'rgba(50, 50, 200, 0.9)';
    ctx.shadowColor = 'rgba(0, 0, 255, 1.0)';
    ctx.drawImage(img, 50, 300);

    for (var i = 0; i < testScenarios.length; i++)
        runTestScenario(testScenarios[i][1],
                        testScenarios[i][2],
                        testScenarios[i][3]);}

async_test(t => {
        img.onload = function() {
            t.step(drawImageToCanvasAndCheckPixels);
            t.done();
        }
}, "Ensure correct behavior of canvas with image shadow. A square with a cut-out top-right corner should be displayed with solid shadow (top) and blur shadow (bottom).");
</script>
</body>