improved B2DHomMatrix

since we know that this is a matrix only used for 2D transforms,
we know that the last row of the matrix is always { 0, 0, 1 }.

Therefore, we don't need to store that information, and
we can simplify some of the computations.

Also remove operations like operator+ which are not legal for
such a matrix.

Change-Id: I482de9a45ebbedf79e3b6033575aab590e61c2d5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/151909
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 7 insertions, 6 deletions

diff --git a/sw/source/core/edit/edfcol.cxx b/sw/source/core/edit/edfcol.cxx
index 47b4eb61684d..1be771b89174 100644
--- a/sw/source/core/edit/edfcol.cxx
+++ b/sw/source/core/edit/edfcol.cxx
@@ -1379,9 +1379,10 @@ static sal_Int16 lcl_GetAngle(const drawing::HomogenMatrix3& rMatrix)
     aTransformation.set(1, 0, rMatrix.Line2.Column1);
     aTransformation.set(1, 1, rMatrix.Line2.Column2);
     aTransformation.set(1, 2, rMatrix.Line2.Column3);
-    aTransformation.set(2, 0, rMatrix.Line3.Column1);
-    aTransformation.set(2, 1, rMatrix.Line3.Column2);
-    aTransformation.set(2, 2, rMatrix.Line3.Column3);
+    // For this to be a valid 2D transform matrix, the last row must be [0,0,1]
+    assert( rMatrix.Line3.Column1 == 0 );
+    assert( rMatrix.Line3.Column2 == 0 );
+    assert( rMatrix.Line3.Column3 == 1 );
 
     aTransformation.decompose(aScale, aTranslate, fRotate, fShear);
     sal_Int16 nDeg = round(basegfx::rad2deg(fRotate));
@@ -1553,9 +1554,9 @@ static void lcl_placeWatermarkInHeader(const SfxWatermarkItem& rWatermark,
     aMatrix.Line2.Column1 = aTransformation.get(1, 0);
     aMatrix.Line2.Column2 = aTransformation.get(1, 1);
     aMatrix.Line2.Column3 = aTransformation.get(1, 2);
-    aMatrix.Line3.Column1 = aTransformation.get(2, 0);
-    aMatrix.Line3.Column2 = aTransformation.get(2, 1);
-    aMatrix.Line3.Column3 = aTransformation.get(2, 2);
+    aMatrix.Line3.Column1 = 0;
+    aMatrix.Line3.Column2 = 0;
+    aMatrix.Line3.Column3 = 1;
     uno::Reference<beans::XPropertySet> xPropertySet(xShape, uno::UNO_QUERY);
     xPropertySet->setPropertyValue(UNO_NAME_ANCHOR_TYPE, uno::Any(text::TextContentAnchorType_AT_CHARACTER));
     uno::Reference<text::XTextContent> xTextContent(xShape, uno::UNO_QUERY);