Function contain

plugins/plugin-contain/src/index.ts:37–81

* Scale the image to the given width and height keeping the aspect ratio. Some parts of the image may be letter boxed. * @param w the width to resize the image to * @param h the height to resize the image to * @param align A bitmask for horizontal and vertical alignment * @param mode a s

(image: I, options: ContainOptions)

   * ```
   */
  contain<I extends JimpClass>(image: I, options: ContainOptions) {
    const {
      w,
      h,
      align = HorizontalAlign.CENTER | VerticalAlign.MIDDLE,
      mode,
    } = ContainOptionsSchema.parse(options);

    const hbits = align & ((1 << 3) - 1);
    const vbits = align >> 3;

    // check if more flags than one is in the bit sets
    if (
      !(
        (hbits !== 0 && !(hbits & (hbits - 1))) ||
        (vbits !== 0 && !(vbits & (vbits - 1)))
      )
    ) {
      throw new Error("only use one flag per alignment direction");
    }

    const alignH = hbits >> 1; // 0, 1, 2
    const alignV = vbits >> 1; // 0, 1, 2

    const f =
      w / h > image.bitmap.width / image.bitmap.height
        ? h / image.bitmap.height
        : w / image.bitmap.width;

    const c = resizeMethods.scale(clone(image), { f, mode });

    image = resizeMethods.resize(image, { w, h, mode });

    image.scan((_, __, idx) => {
      image.bitmap.data.writeUInt32BE(image.background, idx);
    });

    image = blitMethods.blit(image, {
      src: c,
      x: ((image.bitmap.width - c.bitmap.width) / 2) * alignH,
      y: ((image.bitmap.height - c.bitmap.height) / 2) * alignV,
    });

    return image;
  },
};