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/*
* 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.
*/
package com.google.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)
*/
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 < 0 || top < 0 || width < 0 || height < 0 ||
width > dataWidth - left || height > dataHeight - top) {
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.
for (int y = 0; y < height; y++) {
int outputOffset = y * width;
System.arraycopy(yuvData, 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;
}
}
}
}
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