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Can now instantiate this to represent a region of a BufferedImage rather than the whole thing.

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git-svn-id: https://zxing.googlecode.com/svn/trunk@349 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2008-04-07 20:05:11 +00:00
parent a5b385e764
commit 5659a711a2
1 changed files with 49 additions and 11 deletions
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60
javase/src/com/google/zxing/client/j2se/BufferedImageMonochromeBitmapSource.java
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@ -32,11 +32,19 @@ import java.awt.image.BufferedImageOp;
* 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>
*
* <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 srowen@google.com (Sean Owen), Daniel Switkin (dswitkin@google.com)
*/
public final class BufferedImageMonochromeBitmapSource implements MonochromeBitmapSource {
private final BufferedImage image;
private final int left;
private final int top;
private final int width;
private final int height;
private int blackPoint;
private BlackPointEstimationMethod lastMethod;
private int lastArgument;
@ -46,18 +54,43 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
private static final int LUMINANCE_BUCKETS = 1 << LUMINANCE_BITS;
public BufferedImageMonochromeBitmapSource(BufferedImage image) {
this(image, 0, 0, image.getWidth(), image.getHeight());
}
public BufferedImageMonochromeBitmapSource(BufferedImage image, int left, int top, int right, int bottom) {
this.image = image;
blackPoint = 0x7F;
lastMethod = null;
lastArgument = 0;
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;
}
/**
* @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;
}
private int getRGB(int x, int y) {
return image.getRGB(left + x, top + y);
}
private void getRGBRow(int startX, int startY, int[] result) {
image.getRGB(left + startX, top + startY, result.length, 1, result, 0, result.length);
}
public boolean isBlack(int x, int y) {
return computeRGBLuminance(image.getRGB(x, y)) < blackPoint;
return computeRGBLuminance(getRGB(x, y)) < blackPoint;
}
public BitArray getBlackRow(int y, BitArray row, int startX, int getWidth) {
@ -66,7 +99,8 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
} else {
row.clear();
}
int[] pixelRow = image.getRGB(startX, y, getWidth, 1, null, 0, getWidth);
int[] pixelRow = new int[getWidth];
getRGBRow(startX, y, pixelRow);
for (int i = 0; i < getWidth; i++) {
if (computeRGBLuminance(pixelRow[i]) < blackPoint) {
row.set(i);
@ -76,24 +110,22 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
}
public int getHeight() {
return image.getHeight();
return height;
}
public int getWidth() {
return image.getWidth();
return width;
}
public void estimateBlackPoint(BlackPointEstimationMethod method, int argument) throws ReaderException {
if (!method.equals(lastMethod) || argument != lastArgument) {
int width = image.getWidth();
int height = image.getHeight();
int[] histogram = new int[LUMINANCE_BUCKETS];
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);
int pixel = getRGB(startJ + n, startI + n);
histogram[computeRGBLuminance(pixel) >> LUMINANCE_SHIFT]++;
}
} else if (method.equals(BlackPointEstimationMethod.ROW_SAMPLING)) {
@ -101,7 +133,7 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
throw new IllegalArgumentException("Row is not within the image: " + argument);
}
int[] rgbArray = new int[width];
image.getRGB(0, argument, width, 1, rgbArray, 0, width);
getRGBRow(0, argument, rgbArray);
for (int x = 0; x < width; x++) {
histogram[computeRGBLuminance(rgbArray[x]) >> LUMINANCE_SHIFT]++;
}
@ -122,13 +154,19 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
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, image.getWidth());
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(image.getHeight(), image.getWidth(), image.getType());
BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, image.getType());
op.filter(image, rotatedImage);
return new BufferedImageMonochromeBitmapSource(rotatedImage);
return new BufferedImageMonochromeBitmapSource(rotatedImage,
top,
sourceWidth - (left + width),
top + height,
sourceWidth - left);
}
public boolean isRotateSupported() {