/*
- * Copyright 2007 Google Inc.
+ * Copyright 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.
package com.google.zxing.client.j2se;
-import com.google.zxing.BlackPointEstimationMethod;
import com.google.zxing.MonochromeBitmapSource;
-import com.google.zxing.common.BitArray;
-import com.google.zxing.common.BlackPointEstimator;
+import com.google.zxing.common.BaseMonochromeBitmapSource;
+import java.awt.geom.AffineTransform;
+import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
+import java.awt.image.BufferedImageOp;
/**
* <p>An implementation based upon {@link BufferedImage}. This provides access to the
* underlying image as if it were a monochrome image. Behind the scenes, it is evaluating
* the luminance of the underlying image by retrieving its pixels' RGB values.</p>
*
- * @author srowen@google.com (Sean Owen), Daniel Switkin (dswitkin@google.com)
+ * <p>This may also be used to construct a {@link MonochromeBitmapSource}
+ * based on a region of a {@link BufferedImage}; see
+ * {@link #BufferedImageMonochromeBitmapSource(BufferedImage, int, int, int, int)}.</p>
+ *
+ * @author Sean Owen
+ * @author Daniel Switkin (dswitkin@google.com)
*/
-public final class BufferedImageMonochromeBitmapSource implements MonochromeBitmapSource {
+public final class BufferedImageMonochromeBitmapSource extends BaseMonochromeBitmapSource {
private final BufferedImage image;
- private int blackPoint;
- private BlackPointEstimationMethod lastMethod;
- private int lastArgument;
-
- private static final int LUMINANCE_BITS = 5;
- private static final int LUMINANCE_SHIFT = 8 - LUMINANCE_BITS;
- private static final int LUMINANCE_BUCKETS = 1 << LUMINANCE_BITS;
+ private final int left;
+ private final int top;
+ private final int width;
+ private final int height;
+ /**
+ * Creates an instance that uses the entire given image as a source of pixels to decode.
+ *
+ * @param image image to decode
+ */
public BufferedImageMonochromeBitmapSource(BufferedImage image) {
- this.image = image;
- blackPoint = 0x7F;
- lastMethod = null;
- lastArgument = 0;
+ this(image, 0, 0, image.getWidth(), image.getHeight());
}
- public boolean isBlack(int x, int y) {
- return computeRGBLuminance(image.getRGB(x, y)) < blackPoint;
+ /**
+ * Creates an instance that uses only a region of the given image as a source of pixels to decode.
+ *
+ * @param image image to decode a region of
+ * @param left x coordinate of leftmost pixels to decode
+ * @param top y coordinate of topmost pixels to decode
+ * @param right one more than the x coordinate of rightmost pixels to decode. That is, we will decode
+ * pixels whose x coordinate is in [left,right)
+ * @param bottom likewise, one more than the y coordinate of the bottommost pixels to decode
+ */
+ public BufferedImageMonochromeBitmapSource(BufferedImage image, int left, int top, int right, int bottom) {
+ this.image = image;
+ int sourceHeight = image.getHeight();
+ int sourceWidth = image.getWidth();
+ if (left < 0 || top < 0 || right > sourceWidth || bottom > sourceHeight || right <= left || bottom <= top) {
+ throw new IllegalArgumentException("Invalid bounds: (" + top + ',' + left + ") (" + right + ',' + bottom + ')');
+ }
+ this.left = left;
+ this.top = top;
+ this.width = right - left;
+ this.height = bottom - top;
}
- public BitArray getBlackRow(int y, BitArray row, int startX, int getWidth) {
- if (row == null) {
- row = new BitArray(getWidth);
- } else {
- row.clear();
- }
- int[] pixelRow = image.getRGB(startX, y, getWidth, 1, null, 0, getWidth);
- for (int i = 0; i < getWidth; i++) {
- if (computeRGBLuminance(pixelRow[i]) < blackPoint) {
- row.set(i);
- }
- }
- return row;
+ /**
+ * @return underlying {@link BufferedImage} behind this instance. Note that even if this instance
+ * only uses a subset of the full image, the returned value here represents the entire backing image.
+ */
+ public BufferedImage getImage() {
+ return image;
}
+ @Override
public int getHeight() {
- return image.getHeight();
+ return height;
}
+ @Override
public int getWidth() {
- return image.getWidth();
+ return width;
}
- public void estimateBlackPoint(BlackPointEstimationMethod method, int argument) {
- if (!method.equals(lastMethod) || argument != lastArgument) {
- int width = image.getWidth();
- int height = image.getHeight();
- int[] histogram = new int[LUMINANCE_BUCKETS];
- float biasTowardsWhite = 1.0f;
- if (method.equals(BlackPointEstimationMethod.TWO_D_SAMPLING)) {
- int minDimension = width < height ? width : height;
- int startI = height == minDimension ? 0 : (height - width) >> 1;
- int startJ = width == minDimension ? 0 : (width - height) >> 1;
- for (int n = 0; n < minDimension; n++) {
- int pixel = image.getRGB(startJ + n, startI + n);
- histogram[computeRGBLuminance(pixel) >> LUMINANCE_SHIFT]++;
- }
- } else if (method.equals(BlackPointEstimationMethod.ROW_SAMPLING)) {
- if (argument < 0 || argument >= height) {
- throw new IllegalArgumentException("Row is not within the image: " + argument);
- }
- biasTowardsWhite = 2.0f;
- int[] rgbArray = new int[width];
- image.getRGB(0, argument, width, 1, rgbArray, 0, width);
- for (int x = 0; x < width; x++) {
- histogram[computeRGBLuminance(rgbArray[x]) >> LUMINANCE_SHIFT]++;
- }
- } else {
- throw new IllegalArgumentException("Unknown method: " + method);
- }
- blackPoint = BlackPointEstimator.estimate(histogram, biasTowardsWhite) << LUMINANCE_SHIFT;
- lastMethod = method;
- lastArgument = argument;
+ @Override
+ public MonochromeBitmapSource rotateCounterClockwise() {
+ if (!isRotateSupported()) {
+ throw new IllegalStateException("Rotate not supported");
}
+ int sourceWidth = image.getWidth();
+ int sourceHeight = image.getHeight();
+ // 90 degrees counterclockwise:
+ AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);
+ BufferedImageOp op = new AffineTransformOp(transform, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
+ // Note width/height are flipped since we are rotating 90 degrees:
+ BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, image.getType());
+ op.filter(image, rotatedImage);
+ return new BufferedImageMonochromeBitmapSource(rotatedImage,
+ top,
+ sourceWidth - (left + width),
+ top + height,
+ sourceWidth - left);
}
- public BlackPointEstimationMethod getLastEstimationMethod() {
- return lastMethod;
+ @Override
+ public boolean isRotateSupported() {
+ // Can't run AffineTransforms on images of unknown format
+ return image.getType() != BufferedImage.TYPE_CUSTOM;
}
/**
*
* where R, G, and B are values in [0,1].
*/
- private static int computeRGBLuminance(int pixel) {
+ @Override
+ protected int getLuminance(int x, int y) {
+ int pixel = image.getRGB(left + x, top + y);
// Coefficients add up to 1024 to make the divide into a fast shift
return (306 * ((pixel >> 16) & 0xFF) +
601 * ((pixel >> 8) & 0xFF) +
117 * (pixel & 0xFF)) >> 10;
}
+ @Override
+ protected int[] getLuminanceRow(int y, int[] row) {
+ if (row == null || row.length < width) {
+ row = new int[width];
+ }
+ image.getRGB(left, top + y, width, 1, row, 0, width);
+ for (int x = 0; x < width; x++) {
+ int pixel = row[x];
+ row[x] = (306 * ((pixel >> 16) & 0xFF) +
+ 601 * ((pixel >> 8) & 0xFF) +
+ 117 * (pixel & 0xFF)) >> 10;
+ }
+ return row;
+ }
+
+ @Override
+ protected int[] getLuminanceColumn(int x, int[] column) {
+ if (column == null || column.length < height) {
+ column = new int[height];
+ }
+ image.getRGB(left + x, top, 1, height, column, 0, 1);
+ for (int y = 0; y < height; y++) {
+ int pixel = column[y];
+ column[y] = (306 * ((pixel >> 16) & 0xFF) +
+ 601 * ((pixel >> 8) & 0xFF) +
+ 117 * (pixel & 0xFF)) >> 10;
+ }
+ return column;
+ }
+
}
projects / zxing.git / blobdiff