/
subtract.js
43 lines (39 loc) · 1.14 KB
/
subtract.js
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import { validateArrayOfChannels } from '../../util/channel';
import { checkNumberArray } from '../../util/value';
/**
* @memberof Image
* @instance
* @param {*} value
* @param {object} [options]
* @return {this}
*/
export default function subtract(value, options = {}) {
let { channels } = options;
this.checkProcessable('subtract', {
bitDepth: [8, 16],
});
channels = validateArrayOfChannels(this, { channels: channels });
value = checkNumberArray(value);
if (!isNaN(value)) {
for (let j = 0; j < channels.length; j++) {
let c = channels[j];
for (let i = 0; i < this.data.length; i += this.channels) {
this.data[i + c] = Math.max(0, (this.data[i + c] - value) >> 0);
}
}
} else {
if (this.data.length !== value.length) {
throw new Error('subtract: the data size is different');
}
for (let j = 0; j < channels.length; j++) {
let c = channels[j];
for (let i = 0; i < this.data.length; i += this.channels) {
this.data[i + c] = Math.max(
0,
Math.min(this.maxValue, (this.data[i + c] - value[i + c]) >> 0),
);
}
}
}
return this;
}