Hi,
Here is the patch that fixes few errors in the AffineTransform class.
It corrects a small error in shear transformation and fixes
createInverse() to return correct inverse matrix.
Olga.
? .snprj
? libjava.proj
? patch
Index: ChangeLog
===================================================================
RCS file: /cvs/gcc/gcc/libjava/ChangeLog,v
retrieving revision 1.2631
diff -c -p -u -r1.2631 ChangeLog
--- ChangeLog 30 Jan 2004 13:43:14 -0000 1.2631
+++ ChangeLog 30 Jan 2004 19:27:24 -0000
@@ -1,3 +1,11 @@
+2004-01-30 Olga Rodimina <[EMAIL PROTECTED]>
+
+ * java/awt/geom/AffineTransform.java:
+ (shear): Fixed few errors that caused shear
+ transformation to be performed incorrectly.
+ (createInverse): Fixed to return correct
+ inverse of the given matrix.
+
2004-01-30 Mohan Embar <[EMAIL PROTECTED]>
* gnu/java/net/PlainSocketImpl.java
Index: java/awt/geom/AffineTransform.java
===================================================================
RCS file: /cvs/gcc/gcc/libjava/java/awt/geom/AffineTransform.java,v
retrieving revision 1.7
diff -c -p -u -r1.7 AffineTransform.java
--- java/awt/geom/AffineTransform.java 17 Sep 2003 19:06:55 -0000 1.7
+++ java/awt/geom/AffineTransform.java 30 Jan 2004 19:27:26 -0000
@@ -738,9 +738,9 @@ public class AffineTransform implements
*/
public void shear(double shx, double shy)
{
- double n00 = m00 + shx * m01;
+ double n00 = m00 + shy * m01;
double n01 = shx * m00 + m01;
- double n10 = m10 * shy + m11;
+ double n10 = m10 + shy * m11;
double n11 = shx * m10 + m11;
m00 = n00;
m01 = n01;
@@ -996,6 +996,38 @@ public class AffineTransform implements
* map multiple points to the same line or point). A transform exists only
* if getDeterminant() has a non-zero value.
*
+ * The inverse is calculated as:
+ *
+ * <pre>
+ *
+ * Let A be the matrix for which we want to find the inverse:
+ *
+ * A = [ m00 m01 m02 ]
+ * [ m10 m11 m12 ]
+ * [ 0 0 1 ]
+ *
+ *
+ * 1
+ * inverse (A) = --- x adjoint(A)
+ * det
+ *
+ *
+ *
+ * = 1 [ m11 -m01 m01*m12-m02*m11 ]
+ * --- x [ -m10 m00 -m00*m12+m10*m02 ]
+ * det [ 0 0 m00*m11-m10*m01 ]
+ *
+ *
+ *
+ * = [ m11/det -m01/det m01*m12-m02*m11/det ]
+ * [ -m10/det m00/det -m00*m12+m10*m02/det ]
+ * [ 0 0 1 ]
+ *
+ *
+ * </pre>
+ *
+ *
+ *
* @return a new inverse transform
* @throws NoninvertibleTransformException if inversion is not possible
* @see #getDeterminant()
@@ -1006,8 +1038,15 @@ public class AffineTransform implements
double det = getDeterminant();
if (det == 0)
throw new NoninvertibleTransformException("can't invert transform");
- return new AffineTransform(m11 / det, -m10 / det, m01 / det, -m00 / det,
- -m02, -m12);
+
+ double im00 = m11 / det;
+ double im10 = -m10 / det;
+ double im01 = -m01 / det;
+ double im11 = m00 / det;
+ double im02 = (m01 * m12 - m02 * m11) / det;
+ double im12 = (-m00 * m12 + m10 * m02) / det;
+
+ return new AffineTransform (im00, im10, im01, im11, im02, im12);
}
/**
_______________________________________________
Classpath mailing list
[EMAIL PROTECTED]
http://mail.gnu.org/mailman/listinfo/classpath
