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>

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;
     }
 

drawinglayer/source/primitive2d/svggradientprimitive2d.cxx

@@ -404,14 +404,11 @@ namespace drawinglayer
                     aUnitGradientToObject.rotate(atan2(aVector.getY(), aVector.getX()));
                     aUnitGradientToObject.translate(getStart().getX(), getStart().getY());
 
-                    if(!getGradientTransform().isIdentity())
-                    {
-                        aUnitGradientToObject = getGradientTransform() * aUnitGradientToObject;
-                    }
+                    aUnitGradientToObject *= getGradientTransform();
 
                     // create full transform from unit gradient coordinates to object coordinates
                     // including the SvgGradient transformation
-                    aUnitGradientToObject = aObjectTransform * aUnitGradientToObject;
+                    aUnitGradientToObject *= aObjectTransform;
                 }
                 else
                 {
@@ -424,10 +421,7 @@ namespace drawinglayer
                     aUnitGradientToObject.rotate(atan2(aVector.getY(), aVector.getX()));
                     aUnitGradientToObject.translate(aStart.getX(), aStart.getY());
 
-                    if(!getGradientTransform().isIdentity())
-                    {
-                        aUnitGradientToObject = getGradientTransform() * aUnitGradientToObject;
-                    }
+                    aUnitGradientToObject *= getGradientTransform();
                 }
 
                 // create inverse from it
@@ -757,10 +751,7 @@ namespace drawinglayer
                     aUnitGradientToObject.scale(fRadius, fRadius);
                     aUnitGradientToObject.translate(aStart.getX(), aStart.getY());
 
-                    if(!getGradientTransform().isIdentity())
-                    {
-                        aUnitGradientToObject = getGradientTransform() * aUnitGradientToObject;
-                    }
+                    aUnitGradientToObject *= getGradientTransform();
                 }
 
                 // create inverse from it

sw/source/core/layout/wsfrm.cxx

@@ -274,18 +274,8 @@ void TransformableSwFrame::restoreFrameAreas()
 // transform by given B2DHomMatrix
 void TransformableSwFrame::transform(const basegfx::B2DHomMatrix aTransform)
 {
-    if(!aTransform.isIdentity())
-    {
-        if(!maFrameAreaTransformation.isIdentity())
-        {
-            maFrameAreaTransformation *= aTransform;
-        }
-
-        if(!maFramePrintAreaTransformation.isIdentity())
-        {
-            maFramePrintAreaTransformation *= aTransform;
-        }
-    }
+    maFrameAreaTransformation *= aTransform;
+    maFramePrintAreaTransformation *= aTransform;
 }
 
 SwFrame::SwFrame( SwModify *pMod, SwFrame* pSib )