PlanarYUVLuminanceSource.java

/**
 * Copyright (C) 2013 Eesti Vabariigi Valimiskomisjon 
 * (Estonian National Electoral Committee), www.vvk.ee
 *
 * Written in 2013 by AS Finestmedia, www.finestmedia.ee
 *
 * Vote-verification application for Estonian Internet voting system
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * This file incorporates work covered by the following copyright and  
 * permission notice:  
 * 
 * Copyright (C) 2008 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.
 **/

package ee.vvk.ivotingverification.qr;

import android.graphics.Bitmap;

import com.google.zxing.LuminanceSource;

import ee.vvk.ivotingverification.util.Util;

/**
 * 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)
 */
public final class PlanarYUVLuminanceSource extends LuminanceSource {

	private final byte[] yuvData;
	private final int dataWidth;
	private final int dataHeight;
	private final int left;
	private final int top;

	public PlanarYUVLuminanceSource(byte[] yuvData, int dataWidth,
			int dataHeight, int left, int top, int width, int height,
			boolean reverseHorizontal) {
		super(width, height);

		if (left + width > dataWidth || top + height > dataHeight) {
			if (Util.DEBUGGABLE) {
				throw new IllegalArgumentException(
						"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) {
			reverseHorizontal(width, height);
		}
	}

	@Override
	public byte[] getRow(int y, byte[] row) {
		if (y < 0 || y >= getHeight()) {
			if (Util.DEBUGGABLE) {
				throw new IllegalArgumentException(
						"Requested row is outside the image: " + y);
			}
		}
		int width = getWidth();
		if (row == null || row.length < width) {
			row = new byte[width];
		}
		int offset = (y + top) * dataWidth + left;
		System.arraycopy(yuvData, offset, row, 0, width);
		return row;
	}

	@Override
	public byte[] getMatrix() {
		int width = getWidth();
		int height = getHeight();

		if (width == dataWidth && height == dataHeight) {
			return yuvData;
		}

		int area = width * height;
		byte[] matrix = new byte[area];
		int inputOffset = top * dataWidth + left;

		if (width == dataWidth) {
			System.arraycopy(yuvData, inputOffset, matrix, 0, area);
			return matrix;
		}

		byte[] yuv = yuvData;
		for (int y = 0; y < height; y++) {
			int outputOffset = y * width;
			System.arraycopy(yuv, inputOffset, matrix, outputOffset, width);
			inputOffset += dataWidth;
		}
		return matrix;
	}

	@Override
	public boolean isCropSupported() {
		return true;
	}

	public Bitmap renderCroppedGreyscaleBitmap() {
		int width = getWidth();
		int height = getHeight();
		int[] pixels = new int[width * height];
		byte[] yuv = yuvData;
		int inputOffset = top * dataWidth + left;

		for (int y = 0; y < height; y++) {
			int outputOffset = y * width;
			for (int x = 0; x < width; x++) {
				int grey = yuv[inputOffset + x] & 0xff;
				pixels[outputOffset + x] = 0xFF000000 | (grey * 0x00010101);
			}
			inputOffset += dataWidth;
		}

		Bitmap bitmap = Bitmap.createBitmap(width, height,
				Bitmap.Config.ARGB_8888);
		bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
		return bitmap;
	}

	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;
			}
		}
	}
}