import { isNodePattern, throwError } from '@jimp/utils';
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/**
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* Displaces the image based on the provided displacement map
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* @param {object} map the source Jimp instance
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* @param {number} offset the maximum displacement value
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* @param {function(Error, Jimp)} cb (optional) a callback for when complete
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* @returns {Jimp} this for chaining of methods
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*/
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export default () => ({
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displace(map, offset, cb) {
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if (typeof map !== 'object' || map.constructor !== this.constructor) {
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return throwError.call(this, 'The source must be a Jimp image', cb);
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}
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if (typeof offset !== 'number') {
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return throwError.call(this, 'factor must be a number', cb);
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}
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const source = this.cloneQuiet();
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this.scanQuiet(0, 0, this.bitmap.width, this.bitmap.height, function(
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x,
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y,
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idx
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) {
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let displacement = (map.bitmap.data[idx] / 256) * offset;
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displacement = Math.round(displacement);
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const ids = this.getPixelIndex(x + displacement, y);
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this.bitmap.data[ids] = source.bitmap.data[idx];
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this.bitmap.data[ids + 1] = source.bitmap.data[idx + 1];
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this.bitmap.data[ids + 2] = source.bitmap.data[idx + 2];
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});
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if (isNodePattern(cb)) {
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cb.call(this, null, this);
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}
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return this;
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}
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});
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