Related: #i125349# moved clip enhancements to base clipping functionality

(cherry picked from commit 7c5e9b9b3c5c899d63bf171ee1c9050db860337e)

Change-Id: I570e92c78196895bef329eb308eeb68ffc5e23d3

1 files changed, 67 insertions, 0 deletions

diff --git a/basegfx/source/polygon/b2dpolygonclipper.cxx b/basegfx/source/polygon/b2dpolygonclipper.cxx
index b8d4a04bed30..e73c388044e9 100644
--- a/basegfx/source/polygon/b2dpolygonclipper.cxx
+++ b/basegfx/source/polygon/b2dpolygonclipper.cxx
@@ -341,6 +341,73 @@ namespace basegfx
 
             if(rCandidate.count() && rClip.count())
             {
+                // #125349# detect if both given PolyPolygons are indeed ranges
+                bool bBothRectangle(false);
+
+                if(basegfx::tools::isRectangle(rCandidate))
+                {
+                    if(basegfx::tools::isRectangle(rClip))
+                    {
+                        // both are ranges
+                        bBothRectangle = true;
+                    }
+                    else
+                    {
+                        // rCandidate is rectangle -> clip rClip on rRectangle, use the much
+                        // cheaper and numerically more stable clipping against a range
+                        // This simplification (exchanging content and clip) is valid
+                        // since we do a logical AND operation
+                        return clipPolyPolygonOnRange(rClip, rCandidate.getB2DRange(), bInside, bStroke);
+                    }
+                }
+                else if(basegfx::tools::isRectangle(rClip))
+                {
+                    if(basegfx::tools::isRectangle(rCandidate))
+                    {
+                        // both are ranges
+                        bBothRectangle = true;
+                    }
+                    else
+                    {
+                        // rClip is rectangle -> clip rCandidate on rRectangle, use the much
+                        // cheaper and numerically more stable clipping against a range
+                        return clipPolyPolygonOnRange(rCandidate, rClip.getB2DRange(), bInside, bStroke);
+                    }
+                }
+
+                if(bBothRectangle)
+                {
+                    // both are rectangle
+                    if(rCandidate.getB2DRange().equal(rClip.getB2DRange()))
+                    {
+                        // if both are equal -> no change
+                        return rCandidate;
+                    }
+                    else
+                    {
+                        // not equal -> create new intersection from both ranges,
+                        // but much cheaper based on the ranges
+                        basegfx::B2DRange aIntersectionRange(rCandidate.getB2DRange());
+
+                        aIntersectionRange.intersect(rClip.getB2DRange());
+
+                        if(aIntersectionRange.isEmpty())
+                        {
+                            // no common IntersectionRange -> the clip will be empty
+                            return B2DPolyPolygon();
+                        }
+                        else
+                        {
+                            // use common aIntersectionRange as result, convert
+                            // to expected PolyPolygon form
+                            return basegfx::B2DPolyPolygon(
+                                basegfx::tools::createPolygonFromRect(aIntersectionRange));
+                        }
+                    }
+                }
+
+                // one or both are no rectangle - go the hard way and clip PolyPolygon
+                // against PolyPolygon...
                 if(bStroke)
                 {
                     // line clipping, create line snippets by first adding all cut points and