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Opening up the Detector a little to allow extension, such as per Ralf

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git-svn-id: https://zxing.googlecode.com/svn/trunk@1143 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2009-12-08 19:58:01 +00:00
parent 27be3fb930
commit 9f3ee05fe1
4 changed files with 79 additions and 40 deletions
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6
core/src/com/google/zxing/common/DefaultGridSampler.java
View file

@ -38,6 +38,12 @@ public final class DefaultGridSampler extends GridSampler {
p1ToX, p1ToY, p2ToX, p2ToY, p3ToX, p3ToY, p4ToX, p4ToY,
p1FromX, p1FromY, p2FromX, p2FromY, p3FromX, p3FromY, p4FromX, p4FromY);
return sampleGrid(image, dimension, transform);
}
public BitMatrix sampleGrid(BitMatrix image,
int dimension,
PerspectiveTransform transform) throws ReaderException {
BitMatrix bits = new BitMatrix(dimension);
float[] points = new float[dimension << 1];
for (int y = 0; y < dimension; y++) {

7
core/src/com/google/zxing/common/GridSampler.java
View file

@ -92,6 +92,13 @@ public abstract class GridSampler {
float p3FromX, float p3FromY,
float p4FromX, float p4FromY) throws ReaderException;
public BitMatrix sampleGrid(BitMatrix image,
int dimension,
PerspectiveTransform transform) throws ReaderException {
throw new UnsupportedOperationException();
}
/**
* <p>Checks a set of points that have been transformed to sample points on an image against
* the image's dimensions to see if the point are even within the image.</p>

22
core/src/com/google/zxing/common/PerspectiveTransform.java
View file

@ -23,7 +23,7 @@ package com.google.zxing.common;
*
* @author Sean Owen
*/
final class PerspectiveTransform {
public final class PerspectiveTransform {
private final float a11, a12, a13, a21, a22, a23, a31, a32, a33;
@ -41,7 +41,7 @@ final class PerspectiveTransform {
this.a33 = a33;
}
static PerspectiveTransform quadrilateralToQuadrilateral(float x0, float y0,
public static PerspectiveTransform quadrilateralToQuadrilateral(float x0, float y0,
float x1, float y1,
float x2, float y2,
float x3, float y3,
@ -55,7 +55,7 @@ final class PerspectiveTransform {
return sToQ.times(qToS);
}
void transformPoints(float[] points) {
public void transformPoints(float[] points) {
int max = points.length;
float a11 = this.a11;
float a12 = this.a12;
@ -75,7 +75,19 @@ final class PerspectiveTransform {
}
}
static PerspectiveTransform squareToQuadrilateral(float x0, float y0,
/** Convenience method, not optimized for performance. */
public void transformPoints(float[] xValues, float[] yValues) {
int n = xValues.length;
for (int i = 0; i < n; i ++) {
float x = xValues[i];
float y = yValues[i];
float denominator = a13 * x + a23 * y + a33;
xValues[i] = (a11 * x + a21 * y + a31) / denominator;
yValues[i] = (a12 * x + a22 * y + a32) / denominator;
}
}
public static PerspectiveTransform squareToQuadrilateral(float x0, float y0,
float x1, float y1,
float x2, float y2,
float x3, float y3) {
@ -99,7 +111,7 @@ final class PerspectiveTransform {
}
}
private static PerspectiveTransform quadrilateralToSquare(float x0, float y0,
public static PerspectiveTransform quadrilateralToSquare(float x0, float y0,
float x1, float y1,
float x2, float y2,
float x3, float y3) {

38
core/src/com/google/zxing/qrcode/detector/Detector.java
View file

@ -23,6 +23,7 @@ import com.google.zxing.ResultPointCallback;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.DetectorResult;
import com.google.zxing.common.GridSampler;
import com.google.zxing.common.PerspectiveTransform;
import com.google.zxing.qrcode.decoder.Version;
import java.util.Hashtable;
@ -46,6 +47,10 @@ public class Detector {
return image;
}
protected ResultPointCallback getResultPointCallback() {
return resultPointCallback;
}
/**
* <p>Detects a QR Code in an image, simply.</p>
*
@ -117,7 +122,10 @@ public class Detector {
// If we didn't find alignment pattern... well try anyway without it
}
BitMatrix bits = sampleGrid(image, topLeft, topRight, bottomLeft, alignmentPattern, dimension);
PerspectiveTransform transform =
createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);
BitMatrix bits = sampleGrid(image, transform, dimension);
ResultPoint[] points;
if (alignmentPattern == null) {
@ -128,12 +136,11 @@ public class Detector {
return new DetectorResult(bits, points);
}
private static BitMatrix sampleGrid(BitMatrix image,
ResultPoint topLeft,
public PerspectiveTransform createTransform(ResultPoint topLeft,
ResultPoint topRight,
ResultPoint bottomLeft,
ResultPoint alignmentPattern,
int dimension) throws ReaderException {
int dimension) {
float dimMinusThree = (float) dimension - 3.5f;
float bottomRightX;
float bottomRightY;
@ -150,10 +157,7 @@ public class Detector {
sourceBottomRightX = sourceBottomRightY = dimMinusThree;
}
GridSampler sampler = GridSampler.getInstance();
return sampler.sampleGrid(
image,
dimension,
PerspectiveTransform transform = PerspectiveTransform.quadrilateralToQuadrilateral(
3.5f,
3.5f,
dimMinusThree,
@ -170,13 +174,23 @@ public class Detector {
bottomRightY,
bottomLeft.getX(),
bottomLeft.getY());
return transform;
}
private static BitMatrix sampleGrid(BitMatrix image,
PerspectiveTransform transform,
int dimension) throws ReaderException {
GridSampler sampler = GridSampler.getInstance();
return sampler.sampleGrid(image, dimension, transform);
}
/**
* <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
* of the finder patterns and estimated module size.</p>
*/
private static int computeDimension(ResultPoint topLeft,
protected static int computeDimension(ResultPoint topLeft,
ResultPoint topRight,
ResultPoint bottomLeft,
float moduleSize) throws ReaderException {
@ -201,7 +215,8 @@ public class Detector {
* <p>Computes an average estimated module size based on estimated derived from the positions
* of the three finder patterns.</p>
*/
private float calculateModuleSize(ResultPoint topLeft, ResultPoint topRight,
protected float calculateModuleSize(ResultPoint topLeft,
ResultPoint topRight,
ResultPoint bottomLeft) {
// Take the average
return (calculateModuleSizeOneWay(topLeft, topRight) +
@ -329,7 +344,7 @@ public class Detector {
* @return {@link AlignmentPattern} if found, or null otherwise
* @throws ReaderException if an unexpected error occurs during detection
*/
private AlignmentPattern findAlignmentInRegion(float overallEstModuleSize,
protected AlignmentPattern findAlignmentInRegion(float overallEstModuleSize,
int estAlignmentX,
int estAlignmentY,
float allowanceFactor)
@ -365,5 +380,4 @@ public class Detector {
private static int round(float d) {
return (int) (d + 0.5f);
}
}