chromium/src/third_party/blink/web_tests/external/wpt/html/canvas/element/manual/drawing-images-to-the-canvas/drawimage_canvas.html

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<canvas id="dest" height="100" width="100"></canvas>

<script>
var sourceCanvasWidth = sourceCanvasHeight = 50;
var destCanvasWidth = destCanvasHeight = 100;
var blueRect = {x: 0, y: 0, w: 50, h: 50};
var blackRect = {x: 5, y: 5, w: 40, h: 40};
var redPixel = [255, 0, 0, 255];
var bluePixel = [0, 0, 255, 255];
var blackPixel = [0, 0, 0, 255];
var transparentBlackPixel = [0, 0, 0, 0];

var destCanvas = document.getElementById('dest');
var destCtx = destCanvas.getContext('2d');
destCtx.imageSmoothingEnabled = false;

function checkPixel(location, expected) {
    var actual = destCtx.getImageData(location[0], location[1], 1, 1).data;
    assert_array_equals(actual, expected);
}

function PreparePixelTests(blueCheck, blackCheck, redCheck, testDescription) {
    var pixelTests = [];
    for (var i = 0; i < blueCheck.length; i++) {
        var message = testDescription + 'Pixel ' + blueCheck[i][0] + ',' + blueCheck[i][1] + ' should be blue.';
        pixelTests.push([message, blueCheck[i], bluePixel]);
    }
    for (var i = 0; i < blackCheck.length; i++) {
        var message = testDescription + 'Pixel ' + blackCheck[i][0] + ',' + blackCheck[i][1] + ' should be black.';
        pixelTests.push([message, blackCheck[i], blackPixel]);
    }
    for (var i = 0; i < redCheck.length; i++) {
        var message = testDescription + 'Pixel ' + redCheck[i][0] + ',' + redCheck[i][1] + ' should be red.';
        pixelTests.push([message, redCheck[i], redPixel]);
    }
    pixelTests.push([testDescription + 'Pixel outside canvas should be transparent black.\n', [100, 100], transparentBlackPixel]);
    return pixelTests;
}

function drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription) {
    destCtx.fillStyle = 'red';
    destCtx.fillRect(0, 0,  destCanvasWidth, destCanvasHeight);

    var sourceCanvas = document.createElement('canvas');
    sourceCanvas.width = sourceCanvasWidth;
    sourceCanvas.height = sourceCanvasHeight;
    var sourceCtx = sourceCanvas.getContext('2d');
    sourceCtx.fillStyle = 'blue';
    sourceCtx.fillRect(blueRect.x, blueRect.y, blueRect.w, blueRect.h);
    sourceCtx.fillStyle = 'black';
    sourceCtx.fillRect(blackRect.x, blackRect.y, blackRect.w, blackRect.h);
    if (typeof sourceRect.x !== 'undefined')
        destCtx.drawImage(sourceCanvas, sourceRect.x, sourceRect.y, sourceRect.w, sourceRect.h,
                          destRect.x, destRect.y, destRect.w, destRect.h);
    else if (typeof destRect.w !== 'undefined')
        destCtx.drawImage(sourceCanvas, destRect.x, destRect.y, destRect.w, destRect.h);
    else
        destCtx.drawImage(sourceCanvas, destRect.x, destRect.y);
    var pixelTests = PreparePixelTests(blueCheck, blackCheck, redCheck, testDescription);
    generate_tests(checkPixel, pixelTests);
}

var testDescription;
var sourceRect = {}, destRect = {};
var blueCheck, blackCheck, redCheck;

// 2 arguments, the dest origin is 0,0
// The source canvas will be copied to the 0,0 position of the destination canvas
testDescription = 'Test scenario 1: dx = 0, dy = 0 --- ';
destRect = {x: 0, y: 0};
blueCheck = [[0,0], [0,49], [49,0], [49,49]];
blackCheck = [[5,5], [5,44], [44,5], [44,44]];
redCheck = [[50,0], [0,50], [50,50], [99,99]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// 2 arguments, the dest origin is not 0,0
// The source canvas will copied to the 25, 25 position of the destination canvas
testDescription = 'Test scenario 2: dx = 25, dy = 25 --- ';
destRect = {x: 25, y: 25};
blueCheck = [[25,25], [25,74], [74,25], [74,74]];
blackCheck = [[30,30], [30,69], [69,30], [69,69]];
redCheck = [[24,24], [24,75], [75,24], [75,75]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// 4 arguments, the source origin is not 0,0, the dest size is provided
// The source canvas will copied to the 50, 50 position of the destination canvas and
// on an area of 50x50 pixels
testDescription = 'Test scenario 3: dx = 50, dy = 50, dw = 50, dh = 50 --- ';
destRect = {x: 50, y: 50, w: 50, h: 50};
blueCheck = [[50,50], [50,99], [99,50], [99,99]];
blackCheck = [[55,55], [55,94], [94,55], [94,94]];
redCheck = [[0,0], [49,49], [49,99], [99,49]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// 4 arguments, the dest origin is not 0,0 and the dest size is provided but
// does not match the size of the source. The image will be distorted
// The source canvas will copied to the 50,50 position of the destination canvas
// and it will be shrunk to a and area of 20x20
testDescription = 'Test scenario 4: dx = 50, dy = 50, dw = 20, dh = 20 --- ';
destRect = {x: 50, y: 50, w: 20, h: 20};
blueCheck = [[50,50], [50,69], [69,50], [69,69]];
blackCheck = [[52,52], [52,67], [67,52], [67,67]];
redCheck = [[49,49], [49,70], [70,49], [70,70]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// The source canvas will copied to the 50,50 position of the destination canvas
// over an area of 50x25 pixels
// The copied image will be distorted along the x axis
testDescription = 'Test scenario 5: dx = 50, dy = 50, dw = 50, dh = 20 --- ';
destRect = {x: 50, y: 50, w: 50, h: 20};
blueCheck = [[50,50], [50,69], [99,50], [99,69]];
blackCheck = [[55,52], [55,67], [94,52], [94,67]];
redCheck = [[49,49], [49, 69], [99,49], [99,70]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// 8 arguments, both destination and source origins are 0, 0
// An area of 25x25 pixels of the source image will be copied to
// an area of 25x25 pixels of the destination canvas
// destCtx.drawImage(sourceCanvas, 0, 0, 25, 25, 0, 0, 25, 25);
testDescription = 'Test scenario 6: sx = 0, sy = 0, sw = 25, sh = 25, dx = 0, dy = 0, dw = 25, dh = 25 --- ';
sourceRect = {x: 0, y: 0, w: 25, h: 25};
destRect = {x: 0, y: 0, w: 25, h: 25};
blueCheck = [[0,0], [4,4], [0,24], [24,0]];
blackCheck = [[5,5], [5,24], [24,5], [24,24]];
redCheck = [[25,25], [25, 99], [99,25], [99,99]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// 8 arguments the destination origin is not 0,0
// An area of 25x25 pixels of the source image will be copied to
// an area of 25x25 pixels of the destination canvas in the position 25,25
testDescription = 'Test scenario 7: sx = 0, sy = 0, sw = 25, sh = 25, dx = 25, dy = 25, dw = 25, dh = 25 --- ';
sourceRect = {x: 0, y: 0, w: 25, h: 25};
destRect = {x: 25, y: 25, w: 25, h: 25};
blueCheck = [[25,25], [25,49], [49,25], [29,29]];
blackCheck = [[30,30], [30,49], [49,30], [49,49]];
redCheck = [[24,24], [24, 50], [50,24], [50,50]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// The source rectangle overflows the source image
// The source area is clipped to fit the source image
// and the destination are is clipped in the same proportion
testDescription = 'Test scenario 8: sx = 25, sy = 25, sw = 50, sh = 50, dx = 0, dy = 0, dw = 50, dh = 50 --- ';
sourceRect = {x: 25, y: 25, w: 50, h: 50};
destRect = {x: 0, y: 0, w: 50, h: 50};
blueCheck = [[0,20], [20,0], [20,20], [24,24]];
blackCheck = [[0,0], [0,19], [19,0], [19,19]];
redCheck = [[0,25], [25, 0], [25,25], [99,99]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// The destination rectangle has negative width and height. When the source
// rectangle is outside the source image, the source rectangle must be clipped
// to the source image and the destination rectangle must be clipped in the same
// proportion.
testDescription = 'Test scenario 9: sx = 0, sy = 0, sw = 50, sh = 50, dx = 100, dy = 100, dw = -50, dh = -50 --- ';
sourceRect = {x: 0, y: 0, w: 50, h: 50};
destRect = {x: 100, y: 100, w: -50, h: -50};
blueCheck = [[50,50], [50,99], [99,50], [99,99]];
blackCheck = [[55,55], [55,94], [94,55], [94,94]];
redCheck = [[0,0], [49,49], [0,99], [99,0]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// The destination rectangle is larger than the destination canvas
// When the destination rectangle is outside the destination image (the scratch bitmap),
// the pixels that land outside the scratch bitmap are discarded,
// as if the destination was an infinite canvas whose rendering was
// clipped to the dimensions of the scratch bitmap.
testDescription = 'Test scenario 10: sx = 0, sy = 0, sw = 50, sh = 50, dx = 0, dy = 0, dw = 200, dh = 200 --- ';
sourceRect = {x: 0, y: 0, w: 50, h: 50};
destRect = {x: 0, y: 0, w: 200, h: 200};
blueCheck = [[0,0], [0,99], [99,0], [19,19]];
blackCheck = [[20,20], [20,99], [99,20], [99,99]];
redCheck = [];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// The source rectangle is larger than the source canvas
// The source area is clipped to fit the source image
// and the destination are is clipped in the same proportion
testDescription = 'Test scenario 11: sx = 0, sy = 0, sw = 100, sh = 100, dx = 0, dy = 0, dw = 50, dh = 50 --- ';
sourceRect = {x: 0, y: 0, w: 100, h: 100};
destRect = {x: 0, y: 0, w: 50, h: 50};
blueCheck = [[0,0], [1,1], [23,23], [24,24]];
blackCheck = [[3,3], [3,21], [21,3], [21,21]];
redCheck = [[0,25], [25, 0], [25,25], [99,99]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

// Negative coordinates of the source rectangle.
// The source area is clipped to fit the source image and the destination area
// is clipped in the same proportion. In this specific test:
// - source is clipped by 20 from top and left.
// - destination will get proportionally clipped by 50 from top and left as we
// are scaling the source image 2.5 times.
// - the rect will be drawn from 70,70 to 100,100.
testDescription = 'Test scenario 12: sx = -20, sy = -20, sw = 50, sh = 50, dx = 20, dy = 20, dw = 125, dh = 125 --- ';
sourceRect = {x: -20, y: -20, w: 50, h: 50};
destRect = {x: 20, y: 20, w: 125, h: 125};
blueCheck = [[70,70], [70,99], [99,70], [82,82]];
blackCheck = [[84,84], [84,99], [99,84], [99,99]];
redCheck = [[0,69], [69, 0], [69,69]];
drawCanvasOnCanvasUsingDrawImage(sourceRect, destRect, blueCheck, blackCheck, redCheck, testDescription);

</script>