zxing-typescript/src/core/BinaryBitmap.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.
 */

/**
 * This class is the core bitmap class used by ZXing to represent 1 bit data. Reader objects
 * accept a BinaryBitmap and attempt to decode it.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 */

/*namespace com.google.zxing {*/

import Exception from './Exception'
import Binarizer from './Binarizer'
import BitArray from './common/BitArray'
import BitMatrix from './common/BitMatrix'
import LuminanceSource from './LuminanceSource'

export default class BinaryBitmap {
  private matrix: BitMatrix

  public constructor(private binarizer: Binarizer) {
    if (binarizer === null) {
      throw new Exception(Exception.IllegalArgumentException, "Binarizer must be non-null.")
    }
  }

  /**
   * @return The width of the bitmap.
   */
  public getWidth(): number/*int*/ {
    return this.binarizer.getWidth()
  }

  /**
   * @return The height of the bitmap.
   */
  public getHeight(): number/*int*/ {
    return this.binarizer.getHeight()
  }

  /**
   * Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
   * cached data. Callers should assume this method is expensive and call it as seldom as possible.
   * This method is intended for decoding 1D barcodes and may choose to apply sharpening.
   *
   * @param y The row to fetch, which must be in [0, bitmap height)
   * @param row An optional preallocated array. If null or too small, it will be ignored.
   *            If used, the Binarizer will call BitArray.clear(). Always use the returned object.
   * @return The array of bits for this row (true means black).
   * @throws NotFoundException if row can't be binarized
   */
  public getBlackRow(y: number/*int*/, row: BitArray): BitArray  /*throws NotFoundException */ {
    return this.binarizer.getBlackRow(y, row)
  }

  /**
   * Converts a 2D array of luminance data to 1 bit. As above, assume this method is expensive
   * and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or
   * may not apply sharpening. Therefore, a row from this matrix may not be identical to one
   * fetched using getBlackRow(), so don't mix and match between them.
   *
   * @return The 2D array of bits for the image (true means black).
   * @throws NotFoundException if image can't be binarized to make a matrix
   */
  public getBlackMatrix(): BitMatrix /*throws NotFoundException*/ {
    // The matrix is created on demand the first time it is requested, then cached. There are two
    // reasons for this:
    // 1. This work will never be done if the caller only installs 1D Reader objects, or if a
    //    1D Reader finds a barcode before the 2D Readers run.
    // 2. This work will only be done once even if the caller installs multiple 2D Readers.
    if (this.matrix === null || this.matrix === undefined) {
      this.matrix = this.binarizer.getBlackMatrix()
    }
    return this.matrix
  }

  /**
   * @return Whether this bitmap can be cropped.
   */
  public isCropSupported(): boolean {
    return this.binarizer.getLuminanceSource().isCropSupported()
  }

  /**
   * Returns a new object with cropped image data. Implementations may keep a reference to the
   * original data rather than a copy. Only callable if isCropSupported() is true.
   *
   * @param left The left coordinate, which must be in [0,getWidth())
   * @param top The top coordinate, which must be in [0,getHeight())
   * @param width The width of the rectangle to crop.
   * @param height The height of the rectangle to crop.
   * @return A cropped version of this object.
   */
  public crop(left: number/*int*/, top: number/*int*/, width: number/*int*/, height: number/*int*/): BinaryBitmap {
    const newSource: LuminanceSource = this.binarizer.getLuminanceSource().crop(left, top, width, height)
    return new BinaryBitmap(this.binarizer.createBinarizer(newSource))
  }

  /**
   * @return Whether this bitmap supports counter-clockwise rotation.
   */
  public isRotateSupported(): boolean {
    return this.binarizer.getLuminanceSource().isRotateSupported()
  }

  /**
   * Returns a new object with rotated image data by 90 degrees counterclockwise.
   * Only callable if {@link #isRotateSupported()} is true.
   *
   * @return A rotated version of this object.
   */
  public rotateCounterClockwise(): BinaryBitmap {
    const newSource: LuminanceSource = this.binarizer.getLuminanceSource().rotateCounterClockwise()
    return new BinaryBitmap(this.binarizer.createBinarizer(newSource))
  }

  /**
   * Returns a new object with rotated image data by 45 degrees counterclockwise.
   * Only callable if {@link #isRotateSupported()} is true.
   *
   * @return A rotated version of this object.
   */
  public rotateCounterClockwise45(): BinaryBitmap {
    const newSource: LuminanceSource = this.binarizer.getLuminanceSource().rotateCounterClockwise45()
    return new BinaryBitmap(this.binarizer.createBinarizer(newSource))
  }

  /*@Override*/
  public toString(): string {
    try {
      return this.getBlackMatrix().toString()
    } catch (e /*: NotFoundException*/) {
      return ""
    }
  }

}