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nearestPalette.js
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nearestPalette.js
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// top k sorted array of palettes
function nearestPalette(target, palettes, k) {
let nearestPalettes = [];
palettes.forEach((palette) => {
// for each palette in the array of palettes find its every color
let minDistance = Number.MAX_VALUE;
palette.forEach((color) => {
// calculate distance from target color to every color in a palette
let targetDistance = distanceToColor(target, color);
// compare distance with a given value - minDistance and assign the smaller to minDistance
minDistance = Math.min(minDistance, targetDistance);
});
// push distance and palette into a new array after every palette
nearestPalettes.push({ distance: minDistance, palette: palette });
});
// sort all the distance in ascending order
sort(nearestPalettes);
// return top k palettes we found
return nearestPalettes.slice(0, k);
}
//top k sorted array of every color in every palette
function nearestColor(target, palettes, k) {
let nearestColors = [];
// for each palette in the array of palettes find its every color
palettes.forEach((palette) => {
let sortedColors = [];
let minDistance = Number.MAX_VALUE;
palette.forEach((color) => {
// calculate distance from target color to every color in a palette
let targetDistance = distanceToColor(target, color);
// compare distance with a given value - minDistance and assign the smaller to minDistance
minDistance = Math.min(minDistance, targetDistance);
// sort all the distances from target to every color from palette to an array
sortedColors.push({ color: color, distance: targetDistance });
});
//sort the array in ascending order
sort(sortedColors);
// push sorted array in to a new array
nearestColors.push({ distance: minDistance, colors: sortedColors });
});
return nearestColors.slice(0, k);
}
// calculate the distance between 2 colors
function distanceToColor(color1, color2) {
// convert arguments from hex to RGB()
color1 = toRGB(color1);
color2 = toRGB(color2);
// put arguments's values into arrays
const [r1, g1, b1] = color1;
const [r2, g2, b2] = color2;
// calculate the distance using deltaE formula
const drp2 = Math.pow(r1 - r2, 2);
const dgp2 = Math.pow(g1 - g2, 2);
const dbp2 = Math.pow(b1 - b2, 2);
return Math.sqrt(drp2 + dgp2 + dbp2);
}
function toRGB(target) {
// using regular expression to check if target is in hex format
const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(target);
// if it is then parse its values to get RGB()
return result
? [
parseInt(result[1], 16),
parseInt(result[2], 16),
parseInt(result[3], 16),
]
: null;
}
// Sort function in ascending order
function sort(array) {
array.sort(function (a, b) {
return a.distance - b.distance;
});
}
export { nearestPalette, distanceToColor, nearestColor };