71 lines
1.6 KiB
JavaScript
71 lines
1.6 KiB
JavaScript
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self.addEventListener('message', function (e) {
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const { data: { i, pixels, correctDistortion = true, width, height } } = e;
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// This is the old method just by counting pixels
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const oldStore = {};
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//This method applies some weight to the pixels
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const store = {};
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let totalPixelValue = 0;
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let total = pixels.length / 4;
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const threshold = 200;
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for (let i = 0; i < total; i++) {
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const r = pixels[i * 4 + 0] > threshold ? 1 : 0;
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const g = pixels[i * 4 + 1] > threshold ? 1 : 0;
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const b = pixels[i * 4 + 2] > threshold ? 1 : 0;
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const id = r + "-" + g + "-" + b;
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//Caclulate y position of pixel
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const y = Math.floor(i / width);
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// KarlKilian Formel
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const pixelValue = Math.cos(360 / (Math.pow(height, 2)) * Math.pow(y, 2) + (-360 / height) * y + 90);
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oldStore[id] = oldStore[id] + 1 || 1;
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if (id in store) {
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store[id] += pixelValue;
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} else {
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store[id] = pixelValue;
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}
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totalPixelValue += pixelValue;
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}
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const finalResult = {};
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// Normalize stores
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Object.keys(oldStore).forEach(k => {
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finalResult[k] = {
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distortedValue: oldStore[k] / total
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}
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});
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Object.keys(store).forEach(k => {
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finalResult[k].value = store[k] / totalPixelValue;
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});
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// Conver to array for easier
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const result = Object.keys(finalResult).map(key => {
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const [r, g, b] = key.split("-").map((n) => parseInt(n) * 255);
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return {
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id: key,
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color: `rgb(${r},${g},${b})`,
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value: finalResult[key].value,
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distortedValue: finalResult[key].distortedValue
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}
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}).sort((a, b) => a.value > b.value ? -1 : 1)
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self.postMessage({ result, i });
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}, false); |