Flip the image horizontally or vertically. Defaults to horizontal.
Also aliased as mirror
Usage
- @param {boolean} horizontal a Boolean, if true the image will be flipped horizontally
 - @param {boolean} vertical a Boolean, if true the image will be flipped vertically
 - @param {function(Error, Jimp)} cb (optional) a callback for when complete
 
import jimp from 'jimp';
async function main() {
  const image = await jimp.read('test/image.png');
  image.flip();
  image.mirror();
  image.flip(false, true);
}
main();
