52 lines
1.8 KiB
JavaScript
52 lines
1.8 KiB
JavaScript
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import { isNodePattern, throwError } from '@jimp/utils';
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/**
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* Masks a source image on to this image using average pixel colour. A completely black pixel on the mask will turn a pixel in the image completely transparent.
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* @param {Jimp} src the source Jimp instance
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* @param {number} x the horizontal position to blit the image
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* @param {number} y the vertical position to blit the image
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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 (function () {
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return {
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mask: function mask(src) {
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var x = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;
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var y = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 0;
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var cb = arguments.length > 3 ? arguments[3] : undefined;
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if (!(src instanceof 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 x !== 'number' || typeof y !== 'number') {
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return throwError.call(this, 'x and y must be numbers', cb);
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} // round input
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x = Math.round(x);
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y = Math.round(y);
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var w = this.bitmap.width;
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var h = this.bitmap.height;
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var baseImage = this;
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src.scanQuiet(0, 0, src.bitmap.width, src.bitmap.height, function (sx, sy, idx) {
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var destX = x + sx;
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var destY = y + sy;
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if (destX >= 0 && destY >= 0 && destX < w && destY < h) {
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var dstIdx = baseImage.getPixelIndex(destX, destY);
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var data = this.bitmap.data;
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var avg = (data[idx + 0] + data[idx + 1] + data[idx + 2]) / 3;
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baseImage.bitmap.data[dstIdx + 3] *= avg / 255;
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}
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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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});
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//# sourceMappingURL=index.js.map
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