[mapguide-commits] r5437 - trunk/MgDev/Common/Stylization

[svn_mapguide at osgeo.org]

Author: traianstanev
Date: 2010-12-03 10:35:25 -0800 (Fri, 03 Dec 2010)
New Revision: 5437

Modified:
   trunk/MgDev/Common/Stylization/LineBuffer.cpp
   trunk/MgDev/Common/Stylization/LineBuffer.h
Log:
Added a function to return the signed area of a given contour. Same as the existing PolygonArea() call, but without the fabs() and the end.

Modified: trunk/MgDev/Common/Stylization/LineBuffer.cpp
===================================================================
--- trunk/MgDev/Common/Stylization/LineBuffer.cpp	2010-12-03 18:20:44 UTC (rev 5436)
+++ trunk/MgDev/Common/Stylization/LineBuffer.cpp	2010-12-03 18:35:25 UTC (rev 5437)
@@ -2271,8 +2271,7 @@
     return len;
 }
 
-
-double LineBuffer::PolygonArea(int cntr) const
+double LineBuffer::PolygonSignedArea(int cntr) const
 {
     // pointer arithmetic looks ugly, and can be difficult to follow
     // but it produces tighter asm and this routine is called a lot
@@ -2296,10 +2295,16 @@
 
     // make sure we add the close segment
     sum += (*i)*pts[1] - (*(i+1))*pts[0];
-    return 0.5*fabs(sum);
+    return 0.5*sum;
 }
 
 
+double LineBuffer::PolygonArea(int cntr) const
+{
+    return fabs(PolygonSignedArea(cntr));
+}
+
+
 void LineBuffer::MultiPolygonCentroid(double* cx, double* cy) const
 {
     // Computes the centroid of a MultiPolygon.  This is defined to

Modified: trunk/MgDev/Common/Stylization/LineBuffer.h
===================================================================
--- trunk/MgDev/Common/Stylization/LineBuffer.h	2010-12-03 18:20:44 UTC (rev 5436)
+++ trunk/MgDev/Common/Stylization/LineBuffer.h	2010-12-03 18:35:25 UTC (rev 5437)
@@ -142,6 +142,7 @@
     STYLIZATION_API void SetDrawingScale(double drawingScale);
 
     STYLIZATION_API double PolygonArea(int cntr) const;
+    STYLIZATION_API double PolygonSignedArea(int cntr) const;
     STYLIZATION_API double PolylineLength(int cntr) const;
     STYLIZATION_API double PolylineLengthSqr(int cntr) const;