@zxing/library/es2015/core/RGBLuminanceSource.js

TypeScript port of ZXing multi-format 1D/2D barcode image processing library.

/*
 * Copyright 2009 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*namespace com.google.zxing {*/
import './InvertedLuminanceSource'; // required because of circular dependencies between LuminanceSource and InvertedLuminanceSource
import InvertedLuminanceSource from './InvertedLuminanceSource';
import LuminanceSource from './LuminanceSource';
import System from './util/System';
import IllegalArgumentException from './IllegalArgumentException';
/**
 * This class is used to help decode images from files which arrive as RGB data from
 * an ARGB pixel array. It does not support rotation.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 * @author Betaminos
 */
export default class RGBLuminanceSource extends LuminanceSource {
    constructor(luminances, width /*int*/, height /*int*/, dataWidth /*int*/, dataHeight /*int*/, left /*int*/, top /*int*/) {
        super(width, height);
        this.dataWidth = dataWidth;
        this.dataHeight = dataHeight;
        this.left = left;
        this.top = top;
        if (luminances.BYTES_PER_ELEMENT === 4) { // Int32Array
            const size = width * height;
            const luminancesUint8Array = new Uint8ClampedArray(size);
            for (let offset = 0; offset < size; offset++) {
                const pixel = luminances[offset];
                const r = (pixel >> 16) & 0xff; // red
                const g2 = (pixel >> 7) & 0x1fe; // 2 * green
                const b = pixel & 0xff; // blue
                // Calculate green-favouring average cheaply
                luminancesUint8Array[offset] = /*(byte) */ ((r + g2 + b) / 4) & 0xFF;
            }
            this.luminances = luminancesUint8Array;
        }
        else {
            this.luminances = luminances;
        }
        if (undefined === dataWidth) {
            this.dataWidth = width;
        }
        if (undefined === dataHeight) {
            this.dataHeight = height;
        }
        if (undefined === left) {
            this.left = 0;
        }
        if (undefined === top) {
            this.top = 0;
        }
        if (this.left + width > this.dataWidth || this.top + height > this.dataHeight) {
            throw new IllegalArgumentException('Crop rectangle does not fit within image data.');
        }
    }
    /*@Override*/
    getRow(y /*int*/, row) {
        if (y < 0 || y >= this.getHeight()) {
            throw new IllegalArgumentException('Requested row is outside the image: ' + y);
        }
        const width = this.getWidth();
        if (row === null || row === undefined || row.length < width) {
            row = new Uint8ClampedArray(width);
        }
        const offset = (y + this.top) * this.dataWidth + this.left;
        System.arraycopy(this.luminances, offset, row, 0, width);
        return row;
    }
    /*@Override*/
    getMatrix() {
        const width = this.getWidth();
        const height = this.getHeight();
        // If the caller asks for the entire underlying image, save the copy and give them the
        // original data. The docs specifically warn that result.length must be ignored.
        if (width === this.dataWidth && height === this.dataHeight) {
            return this.luminances;
        }
        const area = width * height;
        const matrix = new Uint8ClampedArray(area);
        let inputOffset = this.top * this.dataWidth + this.left;
        // If the width matches the full width of the underlying data, perform a single copy.
        if (width === this.dataWidth) {
            System.arraycopy(this.luminances, inputOffset, matrix, 0, area);
            return matrix;
        }
        // Otherwise copy one cropped row at a time.
        for (let y = 0; y < height; y++) {
            const outputOffset = y * width;
            System.arraycopy(this.luminances, inputOffset, matrix, outputOffset, width);
            inputOffset += this.dataWidth;
        }
        return matrix;
    }
    /*@Override*/
    isCropSupported() {
        return true;
    }
    /*@Override*/
    crop(left /*int*/, top /*int*/, width /*int*/, height /*int*/) {
        return new RGBLuminanceSource(this.luminances, width, height, this.dataWidth, this.dataHeight, this.left + left, this.top + top);
    }
    invert() {
        return new InvertedLuminanceSource(this);
    }
}