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<!DOCTYPE html>
<meta charset="utf-8">
<title>CanvasRenderingContext2D imageSmoothingEnabled test</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<link rel="help" href="https://html.spec.whatwg.org/multipage/scripting.html#image-smoothing">
<script>
function createTestImage() {
var image = document.createElement('canvas');
var imgctx = image.getContext('2d');
imgctx.fillStyle = "#F00";
imgctx.fillRect(0, 0, 2, 2);
imgctx.fillStyle = "#0F0";
imgctx.fillRect(0, 0, 1, 1);
return image;
}
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
assert_true(ctx.imageSmoothingEnabled);
}, "When the canvas context is created, imageSmoothingEnabled must be set to true.");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
ctx.imageSmoothingEnabled = false;
assert_false(ctx.imageSmoothingEnabled);
}, "On getting imageSmoothingEnabled, the user agent must return the last value it was set to.");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
var image = createTestImage();
ctx.scale(10, 10);
ctx.drawImage(image, 0, 0);
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_not_equals(pixels[0], 0);
assert_not_equals(pixels[1], 255);
}, "Test that image smoothing is actually on by default and just the attribute value.");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
ctx.imageSmoothingEnabled = true;
var image = createTestImage();
ctx.scale(10, 10);
ctx.drawImage(image, 0, 0);
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_not_equals(pixels[0], 0);
assert_not_equals(pixels[1], 255);
}, "Test that image smoothing works when imageSmoothingEnabled is set to true");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
var image = createTestImage();
ctx.imageSmoothingEnabled = false;
ctx.scale(10, 10);
ctx.drawImage(image, 0, 0);
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_array_equals(pixels, [0, 255, 0, 255]);
}, "Test that imageSmoothingEnabled = false (nearest-neighbor interpolation) works with drawImage().");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
var image = createTestImage();
ctx.imageSmoothingEnabled = false;
ctx.scale(10, 10);
ctx.fillStyle = ctx.createPattern(image, 'repeat');
ctx.fillRect(0, 0, 10, 10);
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_array_equals(pixels, [0, 255, 0, 255]);
}, "Test that imageSmoothingEnabled = false (nearest-neighbor interpolation) works with fillRect and createPattern().");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
var image = createTestImage();
ctx.imageSmoothingEnabled = false;
ctx.fillStyle = ctx.createPattern(image, 'repeat');
ctx.scale(10, 10);
ctx.rect(0, 0, 10, 10);
ctx.fill();
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_array_equals(pixels, [0, 255, 0, 255]);
}, "Test that imageSmoothingEnabled = false (nearest-neighbor interpolation) works with fill() and createPattern().");
test(function() {
var ctx = document.createElement('canvas').getContext('2d');
var image = createTestImage();
ctx.strokeStyle = ctx.createPattern(image, 'repeat');
ctx.lineWidth = 5;
ctx.imageSmoothingEnabled = false;
ctx.scale(10, 10);
ctx.beginPath();
ctx.moveTo(0, 0);
ctx.lineTo(10, 10);
ctx.stroke();
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_array_equals(pixels, [0, 255, 0, 255]);
}, "Test that imageSmoothingEnabled = false (nearest-neighbor interpolation) works with stroke() and createPattern().");
test(function() {
var repaints = 5;
var ctx = document.createElement('canvas').getContext('2d');
function draw() {
ctx.clearRect(0, 0, 10, 10);
ctx.setTransform(1, 0, 0, 1, 0, 0);
var image = createTestImage();
ctx.imageSmoothingEnabled = false;
ctx.scale(10, 10);
ctx.drawImage(image, 0, 0);
var pixels = ctx.getImageData(9, 9, 1, 1).data;
assert_array_equals(pixels, [0, 255, 0, 255]);
}
while (repaints > 0) {
draw();
repaints = repaints - 1;
}
}, "Test that imageSmoothingEnabled = false (nearest-neighbor interpolation) still works after repaints.");
</script>
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