zxing-typescript/src/core/InvertedLuminanceSource.ts

TypeScript port of ZXing open-source, 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.
 */

import LuminanceSource from './LuminanceSource'

/*namespace com.google.zxing {*/
  
/**
 * A wrapper implementation of {@link LuminanceSource} which inverts the luminances it returns -- black becomes
 * white and vice versa, and each value becomes (255-value).
 * 
 * @author Sean Owen
 */
export default class InvertedLuminanceSource extends LuminanceSource {

  public constructor(private delegate: LuminanceSource) {
    super(delegate.getWidth(), delegate.getHeight())
  }

  /*@Override*/
  public getRow(y: number/*int*/, row?: Uint8ClampedArray): Uint8ClampedArray {
    const sourceRow = this.delegate.getRow(y, row)
    const width: number/*int*/ = this.getWidth()
    for (let i = 0; i < width; i++) {
      sourceRow[i] = /*(byte)*/ (255 - (sourceRow[i] & 0xFF))
    }
    return sourceRow
  }

  /*@Override*/
  public getMatrix(): Uint8ClampedArray {
    const matrix: Uint8ClampedArray = this.delegate.getMatrix()
    const length: number/*int*/ = this.getWidth() * this.getHeight()
    const invertedMatrix = new Uint8ClampedArray(length)
    for (let i = 0; i < length; i++) {
      invertedMatrix[i] = /*(byte)*/ (255 - (matrix[i] & 0xFF))
    }
    return invertedMatrix
  }
  
  /*@Override*/
  public isCropSupported(): boolean {
    return this.delegate.isCropSupported()
  }

  /*@Override*/
  public crop(left: number/*int*/, top: number/*int*/, width: number/*int*/, height: number/*int*/): LuminanceSource {
    return new InvertedLuminanceSource(this.delegate.crop(left, top, width, height))
  }

  /*@Override*/
  public isRotateSupported(): boolean {
    return this.delegate.isRotateSupported()
  }

  /**
   * @return original delegate {@link LuminanceSource} since invert undoes itself
   */
  /*@Override*/
  public invert(): LuminanceSource {
    return this.delegate
  }

  /*@Override*/
  public rotateCounterClockwise(): LuminanceSource {
    return new InvertedLuminanceSource(this.delegate.rotateCounterClockwise())
  }

  /*@Override*/
  public rotateCounterClockwise45(): LuminanceSource {
    return new InvertedLuminanceSource(this.delegate.rotateCounterClockwise45())
  }

}