Pien-Studio/apps/web/lib/brush-painter.test.ts

import { describe, expect, it } from "vitest";
import { buildBrushDabs, clampBrushOptions, hexToRgb } from "./brush-painter";

describe("brush painter pure helpers", () => {
  it("parses valid hex colors and falls back to black", () => {
    expect(hexToRgb("#ff8040")).toEqual({ r: 255, g: 128, b: 64 });
    expect(hexToRgb("00aaee")).toEqual({ r: 0, g: 170, b: 238 });
    expect(hexToRgb("nope")).toEqual({ r: 0, g: 0, b: 0 });
  });

  it("clamps invalid brush options", () => {
    expect(
      clampBrushOptions({ color: "#fff", size: 0, opacity: 2, hardness: -1 }),
    ).toEqual({
      color: "#fff",
      size: 1,
      opacity: 1,
      hardness: 0,
    });
    expect(
      clampBrushOptions({
        color: "#000",
        size: Number.NaN,
        opacity: Number.NaN,
        hardness: Number.NaN,
      }),
    ).toEqual({
      color: "#000",
      size: 1,
      opacity: 1,
      hardness: 1,
    });
  });

  it("interpolates brush dabs including endpoints", () => {
    expect(buildBrushDabs(0, 0, 4, 0, 4)).toEqual([
      { x: 0, y: 0 },
      { x: 1, y: 0 },
      { x: 2, y: 0 },
      { x: 3, y: 0 },
      { x: 4, y: 0 },
    ]);
    expect(buildBrushDabs(2, 3, 2, 3, 10)).toEqual([
      { x: 2, y: 3 },
      { x: 2, y: 3 },
    ]);
  });
});