zxing-js/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 Binarizer from './Binarizer';
import BitArray from './common/BitArray';
import BitMatrix from './common/BitMatrix';
import LuminanceSource from './LuminanceSource';
import IllegalArgumentException from './IllegalArgumentException';

export default class BinaryBitmap {
    private matrix: BitMatrix;

    public constructor(private binarizer: Binarizer) {
        if (binarizer === null) {
            throw new 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 '';
        }
    }

}