2021-05-28 17:05:55 +02:00
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/**
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2021-10-07 09:03:38 +02:00
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* Flood fill.
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*
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* Flood fill, also called seed fill, is an algorithm that determines and alters the area connected to a given node in a
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* multi-dimensional array with some matching attribute. It is used in the "bucket" fill tool of paint programs to fill
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* connected, similarly-colored areas with a different color.
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*
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* (description adapted from https://en.wikipedia.org/wiki/Flood_fill)
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* @see https://www.techiedelight.com/flood-fill-algorithm/
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2021-05-28 17:05:55 +02:00
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*/
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const neighbors = [[-1, -1], [-1, 0], [-1, 1], [0, -1], [0, 1], [1, -1], [1, 0], [1, 1]]
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/**
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2021-10-07 09:03:38 +02:00
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* Implements the flood fill algorithm through a breadth-first approach using a queue.
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*
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* @param rgbData The image to which the algorithm is applied.
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* @param location The start location on the image.
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* @param targetColor The old color to be replaced.
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* @param replacementColor The new color to replace the old one.
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*/
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export function breadthFirstSearch (rgbData, location, targetColor, replacementColor) {
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2021-05-28 17:05:55 +02:00
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if (location[0] < 0 ||
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location[0] >= rgbData.length ||
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location[1] < 0 ||
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location[1] >= rgbData[0].length) {
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throw new Error('location should point to a pixel within the rgbData')
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}
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const queue = []
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queue.push(location)
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while (queue.length > 0) {
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breadthFirstFill(rgbData, location, targetColor, replacementColor, queue)
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}
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}
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/**
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2021-10-07 09:03:38 +02:00
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* Implements the flood fill algorithm through a depth-first approach using recursion.
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*
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* @param rgbData The image to which the algorithm is applied.
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* @param location The start location on the image.
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* @param targetColor The old color to be replaced.
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* @param replacementColor The new color to replace the old one.
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*/
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export function depthFirstSearch (rgbData, location, targetColor, replacementColor) {
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2021-05-28 17:05:55 +02:00
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if (location[0] < 0 ||
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location[0] >= rgbData.length ||
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location[1] < 0 ||
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location[1] >= rgbData[0].length) {
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throw new Error('location should point to a pixel within the rgbData')
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}
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depthFirstFill(rgbData, location, targetColor, replacementColor)
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}
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/**
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2021-10-07 09:03:38 +02:00
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* Utility-function to implement the breadth-first loop.
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*
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* @param rgbData The image to which the algorithm is applied.
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* @param location The start location on the image.
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* @param targetColor The old color to be replaced.
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* @param replacementColor The new color to replace the old one.
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* @param queue The locations that still need to be visited.
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*/
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2021-05-28 17:05:55 +02:00
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function breadthFirstFill (rgbData, location, targetColor, replacementColor, queue) {
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const currentLocation = queue[0]
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queue.shift()
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if (rgbData[currentLocation[0]][currentLocation[1]] === targetColor) {
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rgbData[currentLocation[0]][currentLocation[1]] = replacementColor
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for (let i = 0; i < neighbors.length; i++) {
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const x = currentLocation[0] + neighbors[i][0]
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const y = currentLocation[1] + neighbors[i][1]
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if (x >= 0 && x < rgbData.length && y >= 0 && y < rgbData[0].length) {
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queue.push([x, y])
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}
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}
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}
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}
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/**
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2021-10-07 09:03:38 +02:00
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* Utility-function to implement the depth-first loop.
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*
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* @param rgbData The image to which the algorithm is applied.
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* @param location The start location on the image.
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* @param targetColor The old color to be replaced.
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* @param replacementColor The new color to replace the old one.
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*/
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2021-05-28 17:05:55 +02:00
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function depthFirstFill (rgbData, location, targetColor, replacementColor) {
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if (rgbData[location[0]][location[1]] === targetColor) {
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rgbData[location[0]][location[1]] = replacementColor
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for (let i = 0; i < neighbors.length; i++) {
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const x = location[0] + neighbors[i][0]
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const y = location[1] + neighbors[i][1]
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if (x >= 0 && x < rgbData.length && y >= 0 && y < rgbData[0].length) {
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depthFirstFill(rgbData, [x, y], targetColor, replacementColor)
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}
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}
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}
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}
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