move identity checks into B3DHomMatrix::operator*=

and consequently simplify some call-sites

Change-Id: I301fc4c88fdfb8af75a348a41593a27f4c6567c5
Reviewed-on: https://gerrit.libreoffice.org/59916
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 13 insertions, 2 deletions

diff --git a/basegfx/source/matrix/b3dhommatrix.cxx b/basegfx/source/matrix/b3dhommatrix.cxx
index d23aed896120..e3f3d3d28475 100644
--- a/basegfx/source/matrix/b3dhommatrix.cxx
+++ b/basegfx/source/matrix/b3dhommatrix.cxx
@@ -117,9 +117,20 @@ namespace basegfx
 
     B3DHomMatrix& B3DHomMatrix::operator*=(const B3DHomMatrix& rMat)
     {
-        if(!rMat.isIdentity())
+        if(rMat.isIdentity())
+        {
+            // multiply with identity, no change -> nothing to do
+        }
+        else if(isIdentity())
+        {
+            // we are identity, result will be rMat -> assign
+            *this = rMat;
+        }
+        else
+        {
+            // multiply
             mpImpl->doMulMatrix(*rMat.mpImpl);
-
+        }
         return *this;
     }