Function blit

plugins/plugin-blit/src/index.ts:43–113

* Short for "bit-block transfer". * It involves the transfer of a block of pixel data from one area of a computer's memory to another area, typically for the purpose of rendering images on the screen or manipulating them in various ways. * It's a fundamental operation in computer graphics util

(image: I, options: BlitOptions)

   * ```
   */
  blit<I extends JimpClass>(image: I, options: BlitOptions) {
    const parsed = BlitOptionsSchema.parse(options);
    let {
      // eslint-disable-next-line prefer-const
      src,
      x = 0,
      y = 0,
      srcX = 0,
      srcY = 0,
      srcW = src.bitmap.width,
      srcH = src.bitmap.height,
    } = "bitmap" in parsed ? ({ src: parsed } as BlitOptionsComplex) : parsed;

    if (!("bitmap" in src)) {
      throw new Error("The source must be a Jimp image");
    }

    if (typeof x !== "number" || typeof y !== "number") {
      throw new Error("x and y must be numbers");
    }

    // round input
    x = Math.round(x);
    y = Math.round(y);

    // round input
    srcX = Math.round(srcX);
    srcY = Math.round(srcY);
    srcW = Math.round(srcW);
    srcH = Math.round(srcH);

    const maxWidth = image.bitmap.width;
    const maxHeight = image.bitmap.height;

    scan(src, srcX, srcY, srcW, srcH, function (sx, sy, idx) {
      const xOffset = x + sx - srcX;
      const yOffset = y + sy - srcY;

      if (
        xOffset >= 0 &&
        yOffset >= 0 &&
        maxWidth - xOffset > 0 &&
        maxHeight - yOffset > 0
      ) {
        const dstIdx = image.getPixelIndex(xOffset, yOffset);
        const srcColor = {
          r: src.bitmap.data[idx] || 0,
          g: src.bitmap.data[idx + 1] || 0,
          b: src.bitmap.data[idx + 2] || 0,
          a: src.bitmap.data[idx + 3] || 0,
        };

        const dst = {
          r: image.bitmap.data[dstIdx] || 0,
          g: image.bitmap.data[dstIdx + 1] || 0,
          b: image.bitmap.data[dstIdx + 2] || 0,
          a: image.bitmap.data[dstIdx + 3] || 0,
        };