Engineer at Mapbox, creator of Leaflet, algorithms geek, open source enthusiast, musician, father of twin girls, Ukrainian. 🇺🇦
Published
Edited
Mar 20, 2019
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36 stars
Pseudo-Blue NoiseVariations on Symmetric Nearest Neighbour smoothingPhyllotaxis explainedDelaunay.findTriangleFast and simple prime generatorBest-First SearchSimple rectangle packingNearest Neighbor GraphMinimum Spanning TreeLloyd’s AlgorithmUnderstanding point-in-polygonPrim’s AlgorithmBridson’s AlgorithmThe Delaunay’s Duald3.packEncloseTo Infinity and Back AgainSutherland–Hodgman Clipping
Fast Distance Transform
Also listed in…
Algorithms & Math
edt1d = (grid, offset, stride, length) => {
v[0] = 0;
z[0] = -INF;
z[1] = INF;
for (let q = 0; q < length; q++) f[q] = grid[offset + q * stride];
for (let q = 1, k = 0, s = 0; q < length; q++) {
do {
const r = v[k];
s = (f[q] - f[r] + q * q - r * r) / (q - r) / 2;
} while (s <= z[k--]);
k += 2;
v[k] = q;
z[k] = s;
z[k + 1] = INF;
}
for (let q = 0, k = 0; q < length; q++) {
while (z[k + 1] < q) k++;
const r = v[k];
grid[offset + q * stride] = f[r] + (q - r) * (q - r);
}
}
transformedGrid = {
replay;
const grid = originalGrid.slice();
for (let x = 0; x < width; x++) { // transform each column
edt1d(grid, x, width, height); yield grid;
}
for (let y = 0; y < height; y++) { // transform each row
edt1d(grid, y * width, 1, width); yield grid;
}
return grid;
}
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