Pien-Studio/apps/web/lib/face-blur-renderer.test.ts

import { describe, expect, it, vi } from "vitest";
import { renderFaceBlurRegions } from "./face-blur-renderer";

function makeContext() {
  return {
    fillStyle: "",
    filter: "none",
    imageSmoothingEnabled: true,
    fillRect: vi.fn(),
    drawImage: vi.fn(),
    save: vi.fn(),
    restore: vi.fn(),
  } as unknown as CanvasRenderingContext2D;
}

function makeImage(width = 1200, height = 800) {
  return { naturalWidth: width, naturalHeight: height } as HTMLImageElement;
}

describe("renderFaceBlurRegions", () => {
  it("renders gaussian blur region with source dimensions", () => {
    const ctx = makeContext();
    const image = makeImage();
    renderFaceBlurRegions(
      ctx,
      image,
      {
        method: "gaussian",
        amount: 24,
        regions: [{ x: 120, y: 80, width: 300, height: 200, sourceWidth: 1200, sourceHeight: 800 }],
      },
      600,
      400,
    );

    expect(ctx.save).toHaveBeenCalledOnce();
    expect(ctx.filter).toBe("blur(24px)");
    expect(ctx.drawImage).toHaveBeenCalledWith(image, 120, 80, 300, 200, 60, 40, 150, 100);
    expect(ctx.restore).toHaveBeenCalledOnce();
  });

  it("renders pixelate using sampled offscreen canvas", () => {
    const doc = globalThis.document;
    expect(doc).toBeDefined();
    if (!doc) return;
    const ctx = makeContext();
    const image = makeImage();
    const sampleDrawImage = vi.fn();
    const sampleCtx = { imageSmoothingEnabled: true, drawImage: sampleDrawImage } as unknown as CanvasRenderingContext2D;
    const sampleCanvas = { width: 0, height: 0, getContext: vi.fn(() => sampleCtx) } as unknown as HTMLCanvasElement;
    const nativeCreateElement = doc.createElement.bind(doc);
    const createElement = vi.spyOn(doc, "createElement").mockImplementation((tagName: string) => {
      if (tagName === "canvas") return sampleCanvas;
      return nativeCreateElement(tagName);
    });

    renderFaceBlurRegions(
      ctx,
      image,
      {
        method: "pixelate",
        amount: 10,
        regions: [{ x: 200, y: 100, width: 160, height: 120, sourceWidth: 1200, sourceHeight: 800 }],
      },
      600,
      400,
    );

    expect(sampleCanvas.width).toBe(16);
    expect(sampleCanvas.height).toBe(12);
    expect(sampleDrawImage).toHaveBeenCalledWith(image, 200, 100, 160, 120, 0, 0, 16, 12);
    expect(ctx.drawImage).toHaveBeenCalledWith(sampleCanvas, 0, 0, 16, 12, 100, 50, 80, 60);
    createElement.mockRestore();
  });

  it("renders censor with region color priority", () => {
    const ctx = makeContext();
    const image = makeImage();
    renderFaceBlurRegions(
      ctx,
      image,
      {
        method: "censor",
        amount: 20,
        censorColor: "#ff0000",
        regions: [{ x: 20, y: 30, width: 40, height: 50, sourceWidth: 1200, sourceHeight: 800, censorColor: "#00ff00" }],
      },
      600,
      400,
    );

    expect(ctx.fillStyle).toBe("#00ff00");
    expect(ctx.fillRect).toHaveBeenCalledWith(10, 15, 20, 25);
  });

  it("falls back to legacy region scaling when source dimensions are missing", () => {
    const ctx = makeContext();
    const image = makeImage(2400, 1600);
    renderFaceBlurRegions(
      ctx,
      image,
      {
        method: "gaussian",
        amount: 16,
        regions: [{ x: 100, y: 120, width: 300, height: 200 }],
      },
      600,
      400,
    );

    expect(ctx.drawImage).toHaveBeenCalledWith(image, 400, 480, 1200, 800, 100, 120, 300, 200);
  });
});