From 6b9681c7d334c45f1abe7e865880cb28dee250b6 Mon Sep 17 00:00:00 2001
From: Sven Neumann <sven@gimp.org>
Date: Mon, 7 Jul 2003 18:36:00 +0000
Subject: [PATCH] added gimp_matrix2_mult().

2003-07-07  Sven Neumann  <sven@gimp.org>

	* libgimpmath/gimpmatrix.[ch]: added gimp_matrix2_mult().
---
 ChangeLog                                     |  4 ++
 .../libgimpmath/libgimpmath-sections.txt      |  1 +
 devel-docs/libgimpmath/tmpl/gimpmatrix.sgml   |  9 +++
 libgimpmath/gimpmatrix.c                      | 59 +++++++++++++------
 libgimpmath/gimpmatrix.h                      |  4 +-
 5 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index af27f1cdd1..d236cbd6ef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2003-07-07  Sven Neumann  <sven@gimp.org>
+
+	* libgimpmath/gimpmatrix.[ch]: added gimp_matrix2_mult().
+
 2003-07-07  Sven Neumann  <sven@gimp.org>
 
 	* libgimpbase/gimpbasetypes.h: include <libgimpmath/gimpmathtypes.h>.
diff --git a/devel-docs/libgimpmath/libgimpmath-sections.txt b/devel-docs/libgimpmath/libgimpmath-sections.txt
index f1e2695e61..622025bc3c 100644
--- a/devel-docs/libgimpmath/libgimpmath-sections.txt
+++ b/devel-docs/libgimpmath/libgimpmath-sections.txt
@@ -23,6 +23,7 @@ GimpMatrix2
 GimpMatrix3
 GimpMatrix4
 gimp_matrix2_identity
+gimp_matrix2_mult
 gimp_matrix3_identity
 gimp_matrix3_transform_point
 gimp_matrix3_mult
diff --git a/devel-docs/libgimpmath/tmpl/gimpmatrix.sgml b/devel-docs/libgimpmath/tmpl/gimpmatrix.sgml
index 438a06b373..ca7785f43b 100644
--- a/devel-docs/libgimpmath/tmpl/gimpmatrix.sgml
+++ b/devel-docs/libgimpmath/tmpl/gimpmatrix.sgml
@@ -53,6 +53,15 @@ basic matrix manipulations and tests.
 @matrix: 
 
 
+<!-- ##### FUNCTION gimp_matrix2_mult ##### -->
+<para>
+
+</para>
+
+@matrix1: 
+@matrix2: 
+
+
 <!-- ##### FUNCTION gimp_matrix3_identity ##### -->
 <para>
 
diff --git a/libgimpmath/gimpmatrix.c b/libgimpmath/gimpmatrix.c
index a4668fec8f..61d2c22f4d 100644
--- a/libgimpmath/gimpmatrix.c
+++ b/libgimpmath/gimpmatrix.c
@@ -29,6 +29,7 @@
 
 #define EPSILON 1e-6
 
+
 /**
  * gimp_matrix2_identity:
  * @matrix: A matrix.
@@ -44,6 +45,46 @@ gimp_matrix2_identity (GimpMatrix2 *matrix)
   *matrix = identity;
 }
 
+/**
+ * gimp_matrix2_mult:
+ * @matrix1: The first input matrix.
+ * @matrix2: The second input matrix which will be overwritten by the result.
+ * 
+ * Multiplies two matrices and puts the result into the second one.
+ */
+void
+gimp_matrix2_mult (const GimpMatrix2 *matrix1, 
+		   GimpMatrix2       *matrix2)
+{
+  GimpMatrix2  tmp;
+
+  tmp.coeff[0][0] = (matrix1->coeff[0][0] * matrix2->coeff[0][0] +
+                     matrix1->coeff[0][1] * matrix2->coeff[1][0]);
+  tmp.coeff[0][1] = (matrix1->coeff[0][0] * matrix2->coeff[0][1] +
+                     matrix1->coeff[0][1] * matrix2->coeff[1][1]);
+  tmp.coeff[1][0] = (matrix1->coeff[1][0] * matrix2->coeff[0][0] +
+                     matrix1->coeff[1][1] * matrix2->coeff[1][0]);
+  tmp.coeff[1][1] = (matrix1->coeff[1][0] * matrix2->coeff[0][1] +
+                     matrix1->coeff[1][1] * matrix2->coeff[1][1]);
+
+  *matrix2 = tmp;
+}
+
+/**
+ * gimp_matrix3_identity:
+ * @matrix: A matrix.
+ * 
+ * Sets the matrix to the identity matrix.
+ */
+void
+gimp_matrix3_identity (GimpMatrix3 *matrix)
+{
+  static const GimpMatrix3 identity = { { { 1.0, 0.0, 0.0 },
+                                          { 0.0, 1.0, 0.0 },
+                                          { 0.0, 0.0, 1.0 } } };
+
+  *matrix = identity;
+}
 
 /**
  * gimp_matrix3_transform_point:
@@ -82,7 +123,7 @@ gimp_matrix3_transform_point (const GimpMatrix3 *matrix,
 /**
  * gimp_matrix3_mult:
  * @matrix1: The first input matrix.
- * @matrix2: The second input matrix which will be oeverwritten by the result.
+ * @matrix2: The second input matrix which will be overwritten by the result.
  * 
  * Multiplies two matrices and puts the result into the second one.
  */
@@ -111,22 +152,6 @@ gimp_matrix3_mult (const GimpMatrix3 *matrix1,
   *matrix2 = tmp;
 }
 
-/**
- * gimp_matrix3_identity:
- * @matrix: A matrix.
- * 
- * Sets the matrix to the identity matrix.
- */
-void
-gimp_matrix3_identity (GimpMatrix3 *matrix)
-{
-  static const GimpMatrix3 identity = { { { 1.0, 0.0, 0.0 },
-                                          { 0.0, 1.0, 0.0 },
-                                          { 0.0, 0.0, 1.0 } } };
-
-  *matrix = identity;
-}
-
 /**
  * gimp_matrix3_translate:
  * @matrix: The matrix that is to be translated.
diff --git a/libgimpmath/gimpmatrix.h b/libgimpmath/gimpmatrix.h
index 9f83b5dd08..6c14a97b9f 100644
--- a/libgimpmath/gimpmatrix.h
+++ b/libgimpmath/gimpmatrix.h
@@ -44,7 +44,10 @@ struct _GimpMatrix4
 
 
 void          gimp_matrix2_identity        (GimpMatrix2       *matrix);
+void          gimp_matrix2_mult            (const GimpMatrix2 *matrix1, 
+					    GimpMatrix2       *matrix2);
 
+void          gimp_matrix3_identity        (GimpMatrix3       *matrix);
 void          gimp_matrix3_transform_point (const GimpMatrix3 *matrix, 
 					    gdouble            x, 
 					    gdouble            y,
@@ -52,7 +55,6 @@ void          gimp_matrix3_transform_point (const GimpMatrix3 *matrix,
 					    gdouble           *newy);
 void          gimp_matrix3_mult            (const GimpMatrix3 *matrix1, 
 					    GimpMatrix3       *matrix2);
-void          gimp_matrix3_identity        (GimpMatrix3       *matrix);
 void          gimp_matrix3_translate       (GimpMatrix3       *matrix, 
 					    gdouble            x, 
 					    gdouble            y);