41 lines
1.2 KiB
JavaScript
41 lines
1.2 KiB
JavaScript
import pixelmatch from 'pixelmatch';
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export default {
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toImageDiffEqual: () => {
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const getImageData = img => {
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const canvas = document.createElement('canvas');
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canvas.width = img.width;
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canvas.height = img.height;
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canvas.getContext('2d').drawImage(img, 0, 0);
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return canvas.getContext('2d').getImageData(0, 0, img.width, img.height).data;
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};
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return {
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compare(actual, expected, threshold = 0.1) {
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if (actual.height !== expected.height || actual.width !== expected.width) {
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return {
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pass: false,
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message: `Expected image dimensions (h x w) of ${expected.height}x${expected.width}.
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Received an image with ${actual.height}x${actual.width}`,
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};
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}
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const { width, height } = actual;
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const differentPixels = pixelmatch(
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getImageData(actual),
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getImageData(expected),
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null,
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width,
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height,
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{ threshold },
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);
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return {
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pass: differentPixels < 20,
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message: `${differentPixels} pixels differ more than ${threshold *
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100} percent between input and output.`,
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};
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},
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};
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},
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};
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