tdf#120797: Apply transformation also to the extents of damage

since 7034311d affine transformation
is passed down to drawPolyPolygon and drawPolyLine functions.

The transformation was correctly applied to cairo context, but not
the extents of damage so those had old, untransformed coordinates and
were therefore not redrawn

Change-Id: I61ce005ef8770ce5c4560a9d953cd92f440043be
Reviewed-on: https://gerrit.libreoffice.org/71383Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

remove comment in light of fix for tdf#120797

Change-Id: I3093f764a26abdbdb651596352ba74b7fa1c3306
Reviewed-on: https://gerrit.libreoffice.org/71399
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-on: https://gerrit.libreoffice.org/71511

vcl/headless/svpgdi.cxx

@@ -1143,6 +1143,9 @@ bool SvpSalGraphics::drawPolyLine(
             fMiterMinimumAngle,
             bPixelSnapHairline));
 
+    // if transformation has been applied, transform also extents (ranges)
+    // of damage so they can be correctly redrawn
+    aExtents.transform(rObjectToDevice);
     releaseCairoContext(cr, false, aExtents);
 
     return bRetval;
@@ -1343,21 +1346,9 @@ bool SvpSalGraphics::drawPolyLine(
     }
 
     // extract extents
-    if(nullptr != pExtents)
-    {
-        // This uses cairo_stroke_extents and combines with cairo_clip_extents, so
-        // referring to Cairo-documentation:
-        // "Computes a bounding box in user coordinates covering the area that would
-        //  be affected, (the "inked" area), by a cairo_stroke() operation given the
-        //  current path and stroke parameters."
-        // It *should* use the current set cairo_matrix_t.
+    if (pExtents)
         *pExtents = getClippedStrokeDamage(cr);
 
-        // If not - the following code needs to be used to correct that:
-        // if(!pExtents->isEmpty() && !bObjectToDeviceIsIdentity)
-        //     pExtents->transform(rObjectToDevice);
-    }
-
     // draw and consume
     cairo_stroke(cr);
 
@@ -1490,6 +1481,9 @@ bool SvpSalGraphics::drawPolyPolygon(
         cairo_stroke_preserve(cr);
     }
 
+    // if transformation has been applied, transform also extents (ranges)
+    // of damage so they can be correctly redrawn
+    extents.transform(rObjectToDevice);
     releaseCairoContext(cr, true, extents);
 
     return true;