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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 class is used to help decode images from files which arrive as a grayscale
* pixel array.
*
* @author dswitkin@google.com (Daniel Switkin)
* @author Betaminos
*/
public class GrayscaleLuminanceSource extends LuminanceSource {
private final byte[] luminances;
private final int dataWidth;
private final int dataHeight;
private final int left;
private final int top;
public GrayscaleLuminanceSource(int width, int height, byte[] pixels) {
super(width, height);
luminances = pixels;
dataWidth = width;
dataHeight = height;
left = 0;
top = 0;
}
private GrayscaleLuminanceSource(byte[] pixels,
int dataWidth,
int dataHeight,
int left,
int top,
int width,
int height) {
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.luminances = pixels;
this.dataWidth = dataWidth;
this.dataHeight = dataHeight;
this.left = left;
this.top = top;
}
@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(luminances, 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 luminances;
}
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(luminances, 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(luminances, 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 GrayscaleLuminanceSource(luminances,
dataWidth,
dataHeight,
this.left + left,
this.top + top,
width,
height);
}
@Override
public boolean isRotateSupported() {
return true;
}
@Override
public LuminanceSource rotateCounterClockwise() {
byte[] rotated = new byte[luminances.length];
for (int y = 0; y < dataHeight; y++) {
for (int x = 0; x < dataWidth; x++) {
int i = (y * dataWidth) + x;
int x2 = y;
int y2 = dataWidth - 1 - x;
int j = (y2 * dataHeight) + x2;
rotated[j] = luminances[i];
}
}
int newWidth = getHeight();
int newHeight = getWidth();
int newLeft = top;
int newTop = dataWidth - (left + getWidth());
return new GrayscaleLuminanceSource(rotated, dataHeight, dataWidth, newLeft, newTop, newWidth, newHeight);
}
}
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