Public
Edited
Nov 6, 2023
Importers
1 star
function tilePlacements(tile, w, h) {
// Get all flipped and rotated variations.
const perms = tilePermutations(tile);
const placements = new BigUint64Array(w * h * perms.length);
let idx = 0;
for(const perm of perms) {
const {width, height} = perm;
for(let dy=0; dy < h - height + 1; ++dy) {
for(let dx=0; dx < w - width + 1; ++dx) {
perm.pack(placements, {idx, dx, dy});
idx++;
}
}
}
// Return a trimmed array of packed values.
return placements.slice(0, idx);
}
function tilePermutations(tile) {
const {height, width, at} = tile;
const size = Math.max(height, width), s = size - 1;
const perms = [ ];
for(const flip of [
([i,j]) => [i,j], // normal
([i,j]) => [j,i] // flipped
]) {
for(const rotate of [
([i,j]) => [i,j], // normal
([i,j]) => [j,s-i], // rotate 90
([i,j]) => [s-i,s-j], // rotate 180
([i,j]) => [s-j,i] // rotate 270
]) {
let values = new Uint8Array(size * size);
for(let i=0; i < height; ++i) {
for(let j=0; j < width; ++j) {
if(tile.at(i,j)) {
//if(at(i,j)) {
const [i2,j2] = flip(rotate([i,j]));
values[i2*size + j2] = 1;
}
}
}
const perm = new PixelData(size, size, values.slice()).squeezed();
// Check that this permutation is new.
let isNew = true;
for(const old of perms) if(perm.isEqualTo(old)) {
isNew = false;
break;
}
if(isNew) perms.push(perm);
}
}
return perms;
}
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Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
