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| import { isNodePattern } from '@jimp/utils';
|
| /**
| * Apply a ordered dithering effect
| * @param {function(Error, Jimp)} cb (optional) a callback for when complete
| * @returns {Jimp} this for chaining of methods
| */
| function dither(cb) {
| const rgb565Matrix = [1, 9, 3, 11, 13, 5, 15, 7, 4, 12, 2, 10, 16, 8, 14, 6];
| this.scanQuiet(0, 0, this.bitmap.width, this.bitmap.height, function(
| x,
| y,
| idx
| ) {
| const thresholdId = ((y & 3) << 2) + (x % 4);
| const dither = rgb565Matrix[thresholdId];
| this.bitmap.data[idx] = Math.min(this.bitmap.data[idx] + dither, 0xff);
| this.bitmap.data[idx + 1] = Math.min(
| this.bitmap.data[idx + 1] + dither,
| 0xff
| );
| this.bitmap.data[idx + 2] = Math.min(
| this.bitmap.data[idx + 2] + dither,
| 0xff
| );
| });
|
| if (isNodePattern(cb)) {
| cb.call(this, null, this);
| }
|
| return this;
| }
|
| export default () => ({
| dither565: dither,
| dither16: dither
| });
|
|
