PlanarYUVLuminanceSource.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;

/**
 * This object extends LuminanceSource around an array of YUV data returned from the camera driver,
 * with the option to crop to a rectangle within the full data. This can be used to exclude
 * superfluous pixels around the perimeter and speed up decoding.
 *
 * It works for any pixel format where the Y channel is planar and appears first, including
 * YCbCr_420_SP and YCbCr_422_SP.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 */
final class PlanarYUVLuminanceSource extends LuminanceSource
{
    private static $THUMBNAIL_SCALE_FACTOR = 2;

    private $yuvData;
    private $dataWidth;
    private $dataHeight;
    private $left;
    private $top;

    public function __construct($yuvData,
                                $dataWidth,
                                $dataHeight,
                                $left,
                                $top,
                                $width,
                                $height,
                                $reverseHorizontal)
    {
        parent::__construct($width, $height);

        if ($left + $width > $dataWidth || $top + $height > $dataHeight) {
            throw new \InvalidArgumentException("Crop rectangle does not fit within image data.");
        }

        $this->yuvData    = $yuvData;
        $this->dataWidth  = $dataWidth;
        $this->dataHeight = $dataHeight;
        $this->left       = $left;
        $this->top        = $top;
        if ($reverseHorizontal) {
            $this->reverseHorizontal($width, $height);
        }
    }

    //@Override
    public function getRow($y, $row = null)
    {
        if ($y < 0 || $y >= getHeight()) {
            throw new \InvalidArgumentException("Requested row is outside the image: " + y);
        }
        $width = $this->getWidth();
        if ($row == null || count($row) < $width) {
            $row = [];//new byte[width];
        }
        $offset = ($y + $this->top) * $this->dataWidth + $this->left;
        $row    = arraycopy($this->yuvData, $offset, $row, 0, $width);

        return $row;
    }

    //@Override
    public function getMatrix()
    {
        $width  = $this->getWidth();
        $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->yuvData;
        }

        $area        = $width * $height;
        $matrix      = [];//new byte[area];
        $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) {
            $matrix = arraycopy($this->yuvData, $inputOffset, $matrix, 0, $area);

            return $matrix;
        }

        // Otherwise copy one cropped row at a time.
        $yuv = $this->yuvData;
        for ($y = 0; $y < $height; $y++) {
            $outputOffset = $y * $width;
            $matrix       = arraycopy($this->yuvData, $inputOffset, $matrix, $outputOffset, $width);
            $inputOffset  += $this->dataWidth;
        }

        return $matrix;
    }

    // @Override
    public function isCropSupported()
    {
        return true;
    }

    // @Override
    public function crop($left, $top, $width, $height)
    {
        return new PlanarYUVLuminanceSource($this->yuvData,
            $this->dataWidth,
            $this->dataHeight,
            $this->left + $left,
            $this->top + $top,
            $width,
            $height,
            false);
    }

    public function renderThumbnail()
    {
        $width       = (int)($this->getWidth() / self::$THUMBNAIL_SCALE_FACTOR);
        $height      = (int)($this->getHeight() / self::$THUMBNAIL_SCALE_FACTOR);
        $pixels      = [];//new int[width * height];
        $yuv         = $this->yuvData;
        $inputOffset = $this->top * $this->dataWidth + $this->left;

        for ($y = 0; $y < $height; $y++) {
            $outputOffset = $y * $width;
            for ($x = 0; $x < $width; $x++) {
                $grey                       = ($yuv[$inputOffset + $x * self::$THUMBNAIL_SCALE_FACTOR] & 0xff);
                $pixels[$outputOffset + $x] = (0xFF000000 | ($grey * 0x00010101));
            }
            $inputOffset += $this->dataWidth * self::$THUMBNAIL_SCALE_FACTOR;
        }

        return $pixels;
    }

    /**
     * @return width of image from {@link #renderThumbnail()}
     */
    /*
  public int getThumbnailWidth() {
    return getWidth() / THUMBNAIL_SCALE_FACTOR;
  }*/

    /**
     * @return height of image from {@link #renderThumbnail()}
     */
    /*
  public int getThumbnailHeight() {
    return getHeight() / THUMBNAIL_SCALE_FACTOR;
  }

  private void reverseHorizontal(int width, int height) {
    byte[] yuvData = this.yuvData;
    for (int y = 0, rowStart = top * dataWidth + left; y < height; y++, rowStart += dataWidth) {
        int middle = rowStart + width / 2;
      for (int x1 = rowStart, x2 = rowStart + width - 1; x1 < middle; x1++, x2--) {
            byte temp = yuvData[x1];
        yuvData[x1] = yuvData[x2];
        yuvData[x2] = temp;
      }
    }
  }
*/
}