tdf#121305 Increase accuracy of custom shape circle

The old implementation has used 4 segments and a questionable control
point distance. The patch changes this to use the common
implementation in basegfx. The method in basegfx is extended to allow
to set the start quarter, so that the custom shape circle can get the
same start quarter as it has before. The method descriptions in
basegfx are adapted to the current implementation.

Change-Id: I3a40f81827227ee0037d336bdf3c1ec6fdd64b4b
Reviewed-on: https://gerrit.libreoffice.org/63366
Tested-by: Jenkins
Reviewed-by: Regina Henschel <rb.henschel@t-online.de>

basegfx/source/polygon/b2dpolygontools.cxx

@@ -1768,9 +1768,9 @@ namespace basegfx
             }
         }
 
-        B2DPolygon createPolygonFromEllipse( const B2DPoint& rCenter, double fRadiusX, double fRadiusY )
+        B2DPolygon createPolygonFromEllipse( const B2DPoint& rCenter, double fRadiusX, double fRadiusY, sal_uInt32 nStartQuadrant)
         {
-            B2DPolygon aRetval(createPolygonFromUnitCircle());
+            B2DPolygon aRetval(createPolygonFromUnitCircle(nStartQuadrant));
             const B2DHomMatrix aMatrix(createScaleTranslateB2DHomMatrix(fRadiusX, fRadiusY, rCenter.getX(), rCenter.getY()));
 
             aRetval.transform(aMatrix);

include/basegfx/polygon/b2dpolygontools.hxx

@@ -231,7 +231,7 @@ namespace basegfx
         /** Create a circle polygon with given radius.
 
             This method creates a circle approximation consisting of
-            four cubic bezier segments, which approximate the given
+            12 cubic bezier segments, which approximate the given
             circle with an error of less than 0.5 percent.
 
             @param rCenter
@@ -260,7 +260,7 @@ namespace basegfx
         /** Create an ellipse polygon with given radii.
 
             This method creates an ellipse approximation consisting of
-            four cubic bezier segments, which approximate the given
+            12 cubic bezier segments, which approximate the given
             ellipse with an error of less than 0.5 percent.
 
             @param rCenter
@@ -271,8 +271,11 @@ namespace basegfx
 
             @param fRadiusY
             Radius of the ellipse in Y direction
+
+            @param nStartQuadrant
+            With Y down on screens, 0 = 3 o'clock, 1 = 6 o'clock, 2 = 9 o'clock, 3 = 12 o'clock
          */
-        BASEGFX_DLLPUBLIC B2DPolygon createPolygonFromEllipse( const B2DPoint& rCenter, double fRadiusX, double fRadiusY );
+        BASEGFX_DLLPUBLIC B2DPolygon createPolygonFromEllipse( const B2DPoint& rCenter, double fRadiusX, double fRadiusY, sal_uInt32 nStartQuadrant = 0);
 
         /** Create an unit ellipse polygon with the given angles, from start to end
          */

svx/source/customshapes/EnhancedCustomShape2d.cxx

@@ -1688,41 +1688,11 @@ void EnhancedCustomShape2d::CreateSubPath(
                                 aNewB2DPolygon.append(CreateArc( aRect, Point( static_cast<sal_Int32>(fx1), static_cast<sal_Int32>(fy1) ), Point( static_cast<sal_Int32>(fx2), static_cast<sal_Int32>(fy2) ), false));
                             }
                             else
-                            {   /* SJ: TODO: this block should be replaced sometimes, because the current point
-                                   is not set correct, it also does not use the correct moveto
-                                   point if ANGLEELLIPSETO was used, but the method CreateArc
-                                   is at the moment not able to draw full circles (if startangle is 0
-                                   and endangle 360 nothing is painted :-( */
-                                sal_Int32 nXControl = static_cast<sal_Int32>(static_cast<double>(aRect.GetWidth()) * 0.2835 );
-                                sal_Int32 nYControl = static_cast<sal_Int32>(static_cast<double>(aRect.GetHeight()) * 0.2835 );
-                                Point aCenter( aRect.Center() );
-
-                                // append start point
-                                aNewB2DPolygon.append(basegfx::B2DPoint(aCenter.X(), aRect.Top()));
-
-                                // append four bezier segments
-                                aNewB2DPolygon.appendBezierSegment(
-                                    basegfx::B2DPoint(aCenter.X() + nXControl, aRect.Top()),
-                                    basegfx::B2DPoint(aRect.Right(), aCenter.Y() - nYControl),
-                                    basegfx::B2DPoint(aRect.Right(), aCenter.Y()));
-
-                                aNewB2DPolygon.appendBezierSegment(
-                                    basegfx::B2DPoint(aRect.Right(), aCenter.Y() + nYControl),
-                                    basegfx::B2DPoint(aCenter.X() + nXControl, aRect.Bottom()),
-                                    basegfx::B2DPoint(aCenter.X(), aRect.Bottom()));
-
-                                aNewB2DPolygon.appendBezierSegment(
-                                    basegfx::B2DPoint(aCenter.X() - nXControl, aRect.Bottom()),
-                                    basegfx::B2DPoint(aRect.Left(), aCenter.Y() + nYControl),
-                                    basegfx::B2DPoint(aRect.Left(), aCenter.Y()));
-
-                                aNewB2DPolygon.appendBezierSegment(
-                                    basegfx::B2DPoint(aRect.Left(), aCenter.Y() - nYControl),
-                                    basegfx::B2DPoint(aCenter.X() - nXControl, aRect.Top()),
-                                    basegfx::B2DPoint(aCenter.X(), aRect.Top()));
-
-                                // close, rescue last controlpoint, remove double last point
-                                basegfx::utils::closeWithGeometryChange(aNewB2DPolygon);
+                            {
+                                basegfx::B2DPoint aEllipseCenter(aRect.Center().X(),aRect.Center().Y());
+                                double fRadiusX(aRect.GetWidth()/2.0);
+                                double fRadiusY(aRect.GetHeight()/2.0);
+                                aNewB2DPolygon.append(basegfx::utils::createPolygonFromEllipse(aEllipseCenter,fRadiusX,fRadiusY, 3));
                             }
                         }
                         rSrcPt += 3;