feat: release Colour Tools 0.1.0

tests/palette/sample.test.ts

@@ -0,0 +1,95 @@
+import { describe, expect, it } from "vitest";
+import { samplePixels } from "../../src/palette/sample";
+
+const pixels = (
+  width: number,
+  colours: readonly (readonly [number, number, number, number])[],
+) => ({
+  width,
+  height: colours.length / width,
+  data: new Uint8ClampedArray(colours.flat()),
+});
+
+describe("pixel sampling", () => {
+  it("returns the exact pixel for a zero-radius sample", () => {
+    const result = samplePixels(
+      pixels(2, [
+        [12, 34, 56, 255],
+        [200, 100, 50, 128],
+      ]),
+      1,
+      0,
+      0,
+      "average",
+    );
+
+    expect(result).toMatchObject({
+      r: 200,
+      g: 100,
+      b: 50,
+      a: 128,
+      hex: "#C8643280",
+      pixelCount: 1,
+    });
+  });
+
+  it("uses a circular neighbourhood and alpha-weighted RGB average", () => {
+    const data = pixels(3, [
+      [0, 0, 0, 0],
+      [255, 0, 0, 255],
+      [0, 0, 0, 0],
+      [0, 255, 0, 255],
+      [0, 0, 255, 0],
+      [0, 0, 0, 0],
+      [0, 0, 0, 0],
+      [255, 255, 255, 255],
+      [0, 0, 0, 0],
+    ]);
+    const result = samplePixels(data, 1, 1, 1, "average");
+
+    expect(result).toMatchObject({
+      r: 170,
+      g: 170,
+      b: 85,
+      a: 153,
+      pixelCount: 5,
+    });
+  });
+
+  it("calculates channel medians from visible samples", () => {
+    const result = samplePixels(
+      pixels(3, [
+        [10, 90, 200, 255],
+        [200, 50, 10, 128],
+        [100, 10, 90, 0],
+      ]),
+      1,
+      0,
+      1,
+      "median",
+    );
+
+    expect(result).toMatchObject({
+      r: 105,
+      g: 70,
+      b: 105,
+      a: 128,
+      pixelCount: 3,
+    });
+  });
+
+  it("rejects invalid coordinates and truncated buffers", () => {
+    expect(
+      samplePixels(pixels(1, [[1, 2, 3, 4]]), 1, 0, 0, "average"),
+    ).toBeNull();
+    expect(
+      samplePixels(
+        { width: 2, height: 2, data: new Uint8ClampedArray(4) },
+        0,
+        0,
+        0,
+        "average",
+      ),
+    ).toBeNull();
+  });
+});