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/**
* Converts RGB array to named object
* @param {[]} item, a length 3 array containing 8 bit RGB value
*/
function rgb(item) {
return {
r: item[0],
g: item[1],
b: item[2]
}
}
/**
* Converts XY array to named object
* @param {[]} item, a 2 length array containing x and y values
*/
function xy(item) {
return {
x: item[0],
y: item[1]
}
}
function colorEqual(item1, item2) {
if (!item1 || !item2) {
return false
}
if (Array.isArray(item1)) {
item1 = rgb(item1)
}
if (Array.isArray(item2)) {
item2 = rgb(item2)
}
return item1.r === item2.r
&& item1.g === item2.g
&& item1.b === item2.b
}
function coordsEqual(item1, item2) {
if (!item1 || !item2) {
return false
}
if (Array.isArray(item1)) {
item1 = xy(item1)
}
if (Array.isArray(item2)) {
item2 = xy(item2)
}
return item1.x === item2.x
&& item1.y === item2.y
}
function getPixel(x, y, pixels) {
let row = pixels[y]
if (!row) {
return
}
return row[x]
}
function findContiguousPixels(x, y, pixels, targetColor = getPixel(x, y, pixels), contiguousPixels=[[x, y]]) {
let adjescent = [
[x-1, y],
[x+1, y],
[x, y-1],
[x, y+1]
]
adjescent.forEach((coord) => {
let px = xy(coord)
let pxCol = getPixel(px.x, px.y, pixels)
if (!pxCol) {
return
}
// add adjescents uniquely if they are the target color
let ix = contiguousPixels.findIndex((existingCoord) => coordsEqual(coord, existingCoord))
if (ix !== -1) {
return
}
if (!colorEqual(pxCol, targetColor)) {
return
}
contiguousPixels.push(coord)
let morePixels = findContiguousPixels(px.x, px.y, pixels, targetColor, contiguousPixels)
contiguousPixels.concat(morePixels)
})
return contiguousPixels
}
export {
xy,
rgb,
colorEqual,
coordsEqual,
findContiguousPixels,
getPixel
}
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