src/copy-pixels.js

/**
 * This copies the source pixels to the destination without any alpha blending.
 * @param {Image} srcImage A Jimp image to copy pixels from.
 * @param {number} srcX X position to start copying from (left).
 * @param {number} srcY Y position to start copying from (top).
 * @param {number} srcW The width of the region to copy.
 * @param {number} srcH The height of the region to copy.
 * @param {Image} destImage A Jimp image to paste the pixels to.
 * @param {number} destX X position to start pasting to (left).
 * @param {number} destY Y position to start pasting to (top).
 */
function copyPixels(srcImage, srcX, srcY, srcW, srcH, destImage, destX, destY) {
  srcImage.scan(srcX, srcY, srcW, srcH, (curSrcX, curSrcY, curSrcIndex) => {
    const curDestX = destX + (curSrcX - srcX);
    const curDestY = destY + (curSrcY - srcY);
    const curDestIndex = destImage.getPixelIndex(curDestX, curDestY);
    destImage.bitmap.data[curDestIndex + 0] = srcImage.bitmap.data[curSrcIndex + 0];
    destImage.bitmap.data[curDestIndex + 1] = srcImage.bitmap.data[curSrcIndex + 1];
    destImage.bitmap.data[curDestIndex + 2] = srcImage.bitmap.data[curSrcIndex + 2];
    destImage.bitmap.data[curDestIndex + 3] = srcImage.bitmap.data[curSrcIndex + 3];
  });
}

/**
 * This copies the source pixel to every pixel in the destination rectangle without any alpha blending.
 * @param {Image} srcImage A Jimp image to copy pixel from.
 * @param {number} srcX X position of the source pixel.
 * @param {number} srcY Y position of the source pixel.
 * @param {Image} destImage A Jimp image to paste the pixel to.
 * @param {number} destX X position to start pasting to (left).
 * @param {number} destY Y position to start pasting to (top).
 * @param {number} destW The width of the destination region.
 * @param {number} destH The height of the destination region.
 */
function copyPixelToRect(srcImage, srcX, srcY, destImage, destX, destY, destW, destH) {
  const srcIndex = srcImage.getPixelIndex(srcX, srcY);
  destImage.scan(destX, destY, destW, destH, (curDestX, curDestY, curDestIndex) => {
    destImage.bitmap.data[curDestIndex + 0] = srcImage.bitmap.data[srcIndex + 0];
    destImage.bitmap.data[curDestIndex + 1] = srcImage.bitmap.data[srcIndex + 1];
    destImage.bitmap.data[curDestIndex + 2] = srcImage.bitmap.data[srcIndex + 2];
    destImage.bitmap.data[curDestIndex + 3] = srcImage.bitmap.data[srcIndex + 3];
  });
}

module.exports = { copyPixels, copyPixelToRect };