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>

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