}
float dimMinusThree = (float) dimension - 3.5f;
- JAIPerspectiveTransform transform = JAIPerspectiveTransform.getQuadToQuad(
+ PerspectiveTransform transform = PerspectiveTransform.quadrilateralToQuadrilateral(
3.5f,
3.5f,
dimMinusThree,
points[j] = (float) (j >> 1) + 0.5f;
points[j + 1] = iValue;
}
- transform.transform(points);
+ transform.transformPoints(points);
// Quick check to see if points transformed to something inside the image;
// sufficent to check the endpoints
checkEndpoint(image, points);
*/
public abstract class GridSampler {
- private static final String DEFAULT_IMPL_CLASS =
- "com.google.zxing.qrcode.detector.DefaultGridSampler";
+ private static final String DEFAULT_IMPL_CLASS = "com.google.zxing.qrcode.detector.DefaultGridSampler";
private static String gridSamplerClassName = DEFAULT_IMPL_CLASS;
private static GridSampler gridSampler;
+ /**
+ * <p>Sets the (fully-qualified) name of the implementation of {@link GridSampler} which will be
+ * returned from {@link #getInstance()}.</p>
+ *
+ * @param className {@link GridSampler} implementation to instantiate
+ */
public static void setGridSamplerClassName(String className) {
if (className == null) {
throw new IllegalArgumentException();
gridSamplerClassName = className;
}
+ /**
+ * @return the current implementation of {@link GridSampler}, instantiating one if one does
+ * not already exist. The class which is instantied may be set by
+ * {@link #setGridSamplerClassName(String)}
+ */
public static GridSampler getInstance() {
if (gridSampler == null) {
+ // We don't need to synchronize this -- don't really care if two threads initialize at once.
+ // The second one will win.
try {
Class gridSamplerClass = Class.forName(gridSamplerClassName);
gridSampler = (GridSampler) gridSamplerClass.newInstance();
} catch (ClassNotFoundException cnfe) {
+ // The exceptions below would represent bad programming errors;
+ // For J2ME we're punting them out with RuntimeException
throw new RuntimeException(cnfe.toString());
} catch (IllegalAccessException iae) {
throw new RuntimeException(iae.toString());
return gridSampler;
}
+ /**
+ * <p>Given an image, locations of a QR Code's finder patterns and bottom-right alignment pattern,
+ * and the presumed dimension in modules of the QR Code, implemntations of this method extract
+ * the QR Code from the image by sampling the points in the image which should correspond to the
+ * modules of the QR Code.</p>
+ *
+ * @param image image to sample
+ * @param topLeft top-left finder pattern location
+ * @param topRight top-right finder pattern location
+ * @param bottomLeft bottom-left finder pattern location
+ * @param alignmentPattern bottom-right alignment pattern location
+ * @param dimension dimension of QR Code
+ * @return {@link BitMatrix} representing QR Code's modules
+ * @throws ReaderException if QR Code cannot be reasonably sampled -- for example if the location
+ * of the finder patterns imply a transformation that would require sampling off the image
+ */
protected abstract BitMatrix sampleGrid(MonochromeBitmapSource image,
FinderPattern topLeft,
FinderPattern topRight,
AlignmentPattern alignmentPattern,
int dimension) throws ReaderException;
- protected static void checkEndpoint(MonochromeBitmapSource image, float[] points)
- throws ReaderException {
+ /**
+ * <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 endpoints are even within the image.
+ * This method actually only checks the endpoints since the points are assumed to lie
+ * on a line.</p>
+ *
+ * @param image image into which the points should map
+ * @param points actual points in x1,y1,...,xn,yn form
+ * @throws ReaderException if an endpoint is lies outside the image boundaries
+ */
+ protected static void checkEndpoint(MonochromeBitmapSource image, float[] points) throws ReaderException {
int x = (int) points[0];
int y = (int) points[1];
if (x < 0 || x >= image.getWidth() || y < 0 || y >= image.getHeight()) {
+++ /dev/null
-package com.google.zxing.qrcode.detector;
-
-/**
- * TODO need to reimplement this from scratch. This is derived from jai-core from Sun
- * and it is not clear we can redistribute this modification.
- */
-final class JAIPerspectiveTransform {
-
- private float m00, m01, m02, m10, m11, m12, m20, m21, m22;
-
- JAIPerspectiveTransform() {
- m00 = m11 = m22 = 1.0f;
- m01 = m02 = m10 = m12 = m20 = m21 = 0.0f;
- }
-
- private void makeAdjoint() {
- float m00p = m11 * m22 - m12 * m21;
- float m01p = m12 * m20 - m10 * m22; // flipped sign
- float m02p = m10 * m21 - m11 * m20;
- float m10p = m02 * m21 - m01 * m22; // flipped sign
- float m11p = m00 * m22 - m02 * m20;
- float m12p = m01 * m20 - m00 * m21; // flipped sign
- float m20p = m01 * m12 - m02 * m11;
- float m21p = m02 * m10 - m00 * m12; // flipped sign
- float m22p = m00 * m11 - m01 * m10;
- // Transpose and copy sub-determinants
- m00 = m00p;
- m01 = m10p;
- m02 = m20p;
- m10 = m01p;
- m11 = m11p;
- m12 = m21p;
- m20 = m02p;
- m21 = m12p;
- m22 = m22p;
- }
-
- private static void getSquareToQuad(float x0, float y0,
- float x1, float y1,
- float x2, float y2,
- float x3, float y3,
- JAIPerspectiveTransform tx) {
- float dx3 = x0 - x1 + x2 - x3;
- float dy3 = y0 - y1 + y2 - y3;
- tx.m22 = 1.0f;
- if ((dx3 == 0.0f) && (dy3 == 0.0f)) { // to do: use tolerance
- tx.m00 = x1 - x0;
- tx.m01 = x2 - x1;
- tx.m02 = x0;
- tx.m10 = y1 - y0;
- tx.m11 = y2 - y1;
- tx.m12 = y0;
- tx.m20 = 0.0f;
- tx.m21 = 0.0f;
- } else {
- float dx1 = x1 - x2;
- float dy1 = y1 - y2;
- float dx2 = x3 - x2;
- float dy2 = y3 - y2;
- float invdet = 1.0f / (dx1 * dy2 - dx2 * dy1);
- tx.m20 = (dx3 * dy2 - dx2 * dy3) * invdet;
- tx.m21 = (dx1 * dy3 - dx3 * dy1) * invdet;
- tx.m00 = x1 - x0 + tx.m20 * x1;
- tx.m01 = x3 - x0 + tx.m21 * x3;
- tx.m02 = x0;
- tx.m10 = y1 - y0 + tx.m20 * y1;
- tx.m11 = y3 - y0 + tx.m21 * y3;
- tx.m12 = y0;
- }
- }
-
- private static JAIPerspectiveTransform getSquareToQuad(float x0, float y0,
- float x1, float y1,
- float x2, float y2,
- float x3, float y3) {
- JAIPerspectiveTransform tx = new JAIPerspectiveTransform();
- getSquareToQuad(x0, y0, x1, y1, x2, y2, x3, y3, tx);
- return tx;
- }
-
- private static JAIPerspectiveTransform getQuadToSquare(float x0, float y0,
- float x1, float y1,
- float x2, float y2,
- float x3, float y3) {
- JAIPerspectiveTransform tx = new JAIPerspectiveTransform();
- getSquareToQuad(x0, y0, x1, y1, x2, y2, x3, y3, tx);
- tx.makeAdjoint();
- return tx;
- }
-
- static JAIPerspectiveTransform getQuadToQuad(float x0, float y0,
- float x1, float y1,
- float x2, float y2,
- float x3, float y3,
- float x0p, float y0p,
- float x1p, float y1p,
- float x2p, float y2p,
- float x3p, float y3p) {
- JAIPerspectiveTransform tx1 = getQuadToSquare(x0, y0, x1, y1, x2, y2, x3, y3);
- JAIPerspectiveTransform tx2 = getSquareToQuad(x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p);
- tx1.concatenate(tx2);
- return tx1;
- }
-
- private void concatenate(JAIPerspectiveTransform Tx) {
- float m00p = m00 * Tx.m00 + m10 * Tx.m01 + m20 * Tx.m02;
- float m10p = m00 * Tx.m10 + m10 * Tx.m11 + m20 * Tx.m12;
- float m20p = m00 * Tx.m20 + m10 * Tx.m21 + m20 * Tx.m22;
- float m01p = m01 * Tx.m00 + m11 * Tx.m01 + m21 * Tx.m02;
- float m11p = m01 * Tx.m10 + m11 * Tx.m11 + m21 * Tx.m12;
- float m21p = m01 * Tx.m20 + m11 * Tx.m21 + m21 * Tx.m22;
- float m02p = m02 * Tx.m00 + m12 * Tx.m01 + m22 * Tx.m02;
- float m12p = m02 * Tx.m10 + m12 * Tx.m11 + m22 * Tx.m12;
- float m22p = m02 * Tx.m20 + m12 * Tx.m21 + m22 * Tx.m22;
- m00 = m00p;
- m10 = m10p;
- m20 = m20p;
- m01 = m01p;
- m11 = m11p;
- m21 = m21p;
- m02 = m02p;
- m12 = m12p;
- m22 = m22p;
- }
-
- void transform(float[] points) {
- int max = points.length;
- for (int offset = 0; offset < max; offset += 2) {
- float x = points[offset];
- float y = points[offset + 1];
- float w = m20 * x + m21 * y + m22;
- if (w == 0.0f) {
- points[offset] = x;
- points[offset + 1] = y;
- } else {
- float oneOverW = 1.0f / w;
- points[offset] = (m00 * x + m01 * y + m02) * oneOverW;
- points[offset + 1] = (m10 * x + m11 * y + m12) * oneOverW;
- }
- }
- }
-}
\ No newline at end of file
--- /dev/null
+/*\r
+ * Copyright 2007 Google Inc.\r
+ *\r
+ * Licensed under the Apache License, Version 2.0 (the "License");\r
+ * you may not use this file except in compliance with the License.\r
+ * You may obtain a copy of the License at\r
+ *\r
+ * http://www.apache.org/licenses/LICENSE-2.0\r
+ *\r
+ * Unless required by applicable law or agreed to in writing, software\r
+ * distributed under the License is distributed on an "AS IS" BASIS,\r
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+ * See the License for the specific language governing permissions and\r
+ * limitations under the License.\r
+ */\r
+\r
+/**\r
+ * <p>This class implements a perspective transform in two dimensions. Given four source and four destination\r
+ * points, it will compute the transformation implied between them. The code is based directly upon section\r
+ * 3.4.2 of George Wolberg's "Digital Image Warping"; see pages 54-56.</p>\r
+ *\r
+ * @author srowen@google.com (Sean Owen)\r
+ */\r
+package com.google.zxing.qrcode.detector;\r
+\r
+final class PerspectiveTransform {\r
+\r
+ private final float a11, a12, a13, a21, a22, a23, a31, a32, a33;\r
+\r
+ private PerspectiveTransform(float a11, float a12, float a13,\r
+ float a21, float a22, float a23,\r
+ float a31, float a32, float a33) {\r
+ this.a11 = a11;\r
+ this.a12 = a12;\r
+ this.a13 = a13;\r
+ this.a21 = a21;\r
+ this.a22 = a22;\r
+ this.a23 = a23;\r
+ this.a31 = a31;\r
+ this.a32 = a32;\r
+ this.a33 = a33;\r
+ }\r
+\r
+ static PerspectiveTransform quadrilateralToQuadrilateral(float x0, float y0,\r
+ float x1, float y1,\r
+ float x2, float y2,\r
+ float x3, float y3,\r
+ float x0p, float y0p,\r
+ float x1p, float y1p,\r
+ float x2p, float y2p,\r
+ float x3p, float y3p) {\r
+ return quadrilateralToSquare(x0, y0, x1, y1, x2, y2, x3, y3).times(\r
+ squareToQuadrilateral(x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p));\r
+ }\r
+\r
+ void transformPoints(float[] points) {\r
+ for (int i = 0; i < points.length; i += 2) {\r
+ float x = points[i];\r
+ float y = points[i+1];\r
+ points[i] = a11*x + a12*y + a13;\r
+ points[i+1] = a21*x + a22*y + a23;\r
+ }\r
+ }\r
+\r
+ private static PerspectiveTransform squareToQuadrilateral(float x0, float y0,\r
+ float x1, float y1,\r
+ float x2, float y2,\r
+ float x3, float y3) {\r
+ float dx1 = x1 - x2;\r
+ float dx2 = x3 - x2;\r
+ float dx3 = x0 - x1 + x2 - x3;\r
+ float dy1 = y1 - y2;\r
+ float dy2 = y3 - y2;\r
+ float dy3 = y0 - y1 + y2 - y3;\r
+ float denominator = dx1*dy2 - dx2*dy1;\r
+ float a13 = (dx3*dy2 - dx2*dy3) / denominator;\r
+ float a23 = (dx1*dy3 - dx3*dy1) / denominator;\r
+\r
+ return new PerspectiveTransform(x1 - x0 + a13*x1,\r
+ y1 - y0 + a13*y1,\r
+ a13,\r
+ x3 - x0 + a23*x3,\r
+ y3 - y0 + a23*y3,\r
+ a23,\r
+ x0,\r
+ y0,\r
+ 1.0f);\r
+ }\r
+\r
+ private static PerspectiveTransform quadrilateralToSquare(float x0, float y0,\r
+ float x1, float y1,\r
+ float x2, float y2,\r
+ float x3, float y3) {\r
+ // Here, the adjoint serves as the inverse:\r
+ return squareToQuadrilateral(x0, y0, x1, y1, x2, y2, x3, y3).buildAdjoint();\r
+ }\r
+\r
+ private PerspectiveTransform buildAdjoint() {\r
+ // Adjoint is the transpose of the cofactor matrix:\r
+ return new PerspectiveTransform(a22*a33 - a23*a32,\r
+ a12*a33 - a13*a32,\r
+ a12*a23 - a13*a22,\r
+ a21*a33 - a23*a31,\r
+ a11*a33 - a13*a31,\r
+ a11*a23 - a13*a21,\r
+ a21*a32 - a22*a31,\r
+ a11*a32 - a12*a31,\r
+ a11*a22 - a12*a21);\r
+ }\r
+\r
+ private PerspectiveTransform times(PerspectiveTransform other) {\r
+ return new PerspectiveTransform(a11*other.a11 + a12*other.a21 + a13*other.a31,\r
+ a11*other.a12 + a12*other.a22 + a13*other.a32,\r
+ a11*other.a13 + a12*other.a23 + a13*other.a33,\r
+ a21*other.a11 + a22*other.a21 + a23*other.a31,\r
+ a21*other.a12 + a22*other.a22 + a23*other.a32,\r
+ a21*other.a13 + a22*other.a23 + a23*other.a33,\r
+ a31*other.a11 + a32*other.a21 + a33*other.a31,\r
+ a31*other.a12 + a32*other.a22 + a33*other.a33,\r
+ a31*other.a13 + a32*other.a23 + a33*other.a33);\r
+ }\r
+\r
+}\r
projects / zxing.git / commitdiff