PlanarYUVLuminanceSource.java

package com.zbar.lib.bitmap;

public final class PlanarYUVLuminanceSource extends LuminanceSource {

	private static final int THUMBNAIL_SCALE_FACTOR = 2;

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

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

		// If the width matches the full width of the underlying data, perform a
		// single copy.
		if (width == dataWidth) {
			System.arraycopy(yuvData, inputOffset, matrix, 0, area);
			return matrix;
		}

		// Otherwise copy one cropped row at a time.
		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;
	}

	@Override
	public LuminanceSource crop(int left, int top, int width, int height) {
		return new PlanarYUVLuminanceSource(yuvData, dataWidth, dataHeight, this.left + left, this.top + top, width, height, false);
	}

	public int[] renderThumbnail() {
		int width = getWidth() / THUMBNAIL_SCALE_FACTOR;
		int height = getHeight() / THUMBNAIL_SCALE_FACTOR;
		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 * THUMBNAIL_SCALE_FACTOR] & 0xff;
				pixels[outputOffset + x] = 0xFF000000 | (grey * 0x00010101);
			}
			inputOffset += dataWidth * 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;
			}
		}
	}

}