grokbot_ty
0dd5d255ec
Sheet gaps after black/green removal left stray chunks in the bitset. After keep predicates, zero all but the largest 4-connected component and recompute slabPx before bbox / slabBounds.
69 lines
2.4 KiB
TypeScript
69 lines
2.4 KiB
TypeScript
import { test } from 'node:test';
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import assert from 'node:assert/strict';
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import { keepLargestComponent } from './largestComponent.ts';
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test('keepLargestComponent: two blobs → only larger remains', () => {
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// 10×6 grid: large 4×3 block (12 px) at left, small 2×2 (4 px) at right
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const W = 10, H = 6;
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const bitset = new Uint8Array(W * H);
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for (let y = 1; y <= 3; y++)
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for (let x = 1; x <= 4; x++) bitset[y * W + x] = 1;
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for (let y = 2; y <= 3; y++)
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for (let x = 7; x <= 8; x++) bitset[y * W + x] = 1;
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const before = bitset.reduce((a, c) => a + c, 0);
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assert.equal(before, 16);
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const slabPx = keepLargestComponent(bitset, W, H);
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assert.equal(slabPx, 12, 'slabPx is pixel count of largest blob');
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// Large blob intact
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for (let y = 1; y <= 3; y++)
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for (let x = 1; x <= 4; x++)
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assert.equal(bitset[y * W + x], 1, `large (${x},${y}) kept`);
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// Small blob zeroed
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for (let y = 2; y <= 3; y++)
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for (let x = 7; x <= 8; x++)
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assert.equal(bitset[y * W + x], 0, `small (${x},${y}) removed`);
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assert.equal(bitset.reduce((a, c) => a + c, 0), 12);
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});
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test('keepLargestComponent: empty bitset → 0', () => {
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const bitset = new Uint8Array(4 * 4);
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assert.equal(keepLargestComponent(bitset, 4, 4), 0);
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});
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test('keepLargestComponent: single blob unchanged', () => {
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const W = 5, H = 5;
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const bitset = new Uint8Array(W * H);
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for (let y = 1; y <= 3; y++)
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for (let x = 1; x <= 3; x++) bitset[y * W + x] = 1;
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const slabPx = keepLargestComponent(bitset, W, H);
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assert.equal(slabPx, 9);
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assert.equal(bitset.reduce((a, c) => a + c, 0), 9);
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});
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test('keepLargestComponent: 4-connected — diagonal touch is two components', () => {
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// Two pixels only touching diagonally; larger is the two-pixel L on the left
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// of a separate single pixel that is diagonal to nothing of equal size...
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// Layout: three pixels as an L (size 3) and one diagonal fleck (size 1)
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// . # .
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// # # .
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// . . #
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const W = 3, H = 3;
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const bitset = new Uint8Array(W * H);
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bitset[0 * W + 1] = 1;
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bitset[1 * W + 0] = 1;
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bitset[1 * W + 1] = 1;
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bitset[2 * W + 2] = 1; // diagonal-only to the L
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const slabPx = keepLargestComponent(bitset, W, H);
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assert.equal(slabPx, 3);
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assert.equal(bitset[2 * W + 2], 0, 'diagonal fleck removed under 4-conn');
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assert.equal(bitset[0 * W + 1], 1);
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assert.equal(bitset[1 * W + 0], 1);
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assert.equal(bitset[1 * W + 1], 1);
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});
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