BinaryBitmap.php

<?php
/*
* 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 Zxing;

use Zxing\Common\BitMatrix;

/**
 * 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)
 */
final class BinaryBitmap
{
    private $binarizer;
    private $matrix;

    public function __construct(Binarizer $binarizer)
    {
        if ($binarizer === null) {
            throw new \InvalidArgumentException("Binarizer must be non-null.");
        }
        $this->binarizer = $binarizer;
    }

    /**
     * @return int The width of the bitmap.
     */
    public function getWidth()
    {
        return $this->binarizer->getWidth();
    }

    /**
     * @return int The height of the bitmap.
     */
    public function getHeight()
    {
        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 array The array of bits for this row (true means black).
     * @throws NotFoundException if row can't be binarized
     */
    public function getBlackRow($y, $row)
    {
        return $this->binarizer->getBlackRow($y, $row);
    }

    /**
     * @return bool Whether this bitmap can be cropped.
     */
    public function isCropSupported()
    {
        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 BinaryBitmap A cropped version of this object.
     */
    public function crop($left, $top, $width, $height)
    {
        $newSource = $this->binarizer->getLuminanceSource()->crop($left, $top, $width, $height);

        return new BinaryBitmap($this->binarizer->createBinarizer($newSource));
    }

    /**
     * @return Whether this bitmap supports counter-clockwise rotation.
     */
    public function isRotateSupported()
    {
        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 BinaryBitmap A rotated version of this object.
     */
    public function rotateCounterClockwise()
    {
        $newSource = $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 BinaryBitmap A rotated version of this object.
     */
    public function rotateCounterClockwise45()
    {
        $newSource = $this->binarizer->getLuminanceSource()->rotateCounterClockwise45();

        return new BinaryBitmap($this->binarizer->createBinarizer($newSource));
    }

    public function toString()
    {
        try {
            return $this->getBlackMatrix()->toString();
        } catch (NotFoundException $e) {
        }

        return '';
    }

    /**
     * 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 BitMatrix The 2D array of bits for the image (true means black).
     * @throws NotFoundException if image can't be binarized to make a matrix
     */
    public function getBlackMatrix()
    {
        // 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 = $this->binarizer->getBlackMatrix();
        }

        return $this->matrix;
    }
}