feat: implement inpainting functionality with mask handling

- Added `createMaskedPixelReplacementSource` function to handle pixel replacement using inpainting.
- Introduced `buildInpaintBundle` to prepare inpainting data including mask generation and validation.
- Created utility functions for mask operations such as `applyMaskedContentModeToRgba`, `expandRectWithinBounds`, and others for mask manipulation.
- Developed tests for inpainting preparation and mask raster utilities to ensure functionality and correctness.
- Implemented mask raster operations including inversion, feathering, blurring, and more.

view/mask/maskRaster.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, test } from "bun:test";
+import { cropMaskValuesToRgba, expandRectWithinBounds, invertMaskValues } from "./maskRaster";
+
+describe("mask raster utilities", () => {
+  test("exports the normalized drawn mask without filling the whole crop", () => {
+    const revealedMask = new Uint8ClampedArray(4 * 3).fill(255);
+    revealedMask[1 * 4 + 2] = 0;
+
+    const inpaintMask = invertMaskValues(revealedMask);
+    const rgba = cropMaskValuesToRgba(inpaintMask, 4, 3, { x: 1, y: 0, w: 3, h: 3 }, 4, 4);
+    const activePixels = activeRedPixels(rgba);
+
+    expect(activePixels).toEqual([{ x: 1, y: 1 }]);
+    for (let pixel = 0; pixel < rgba.length / 4; pixel += 1) expect(rgba[pixel * 4 + 3]).toBe(255);
+  });
+
+  test("expands masked-area crops to the model minimum when possible", () => {
+    expect(expandRectWithinBounds({ x: 20, y: 20, w: 4, h: 4 }, 4, { w: 100, h: 100 }, 8, 64)).toEqual({
+      x: 0,
+      y: 0,
+      w: 64,
+      h: 64,
+    });
+    expect(expandRectWithinBounds({ x: 80, y: 80, w: 4, h: 4 }, 4, { w: 100, h: 100 }, 8, 64)).toEqual({
+      x: 36,
+      y: 36,
+      w: 64,
+      h: 64,
+    });
+  });
+});
+
+function activeRedPixels(rgba: Uint8ClampedArray) {
+  const width = 4;
+  const pixels: Array<{ x: number; y: number }> = [];
+  for (let pixel = 0; pixel < rgba.length / 4; pixel += 1) {
+    if ((rgba[pixel * 4] ?? 0) > 127) pixels.push({ x: pixel % width, y: Math.floor(pixel / width) });
+  }
+  return pixels;
+}