Partially fix 1684240: gets rid of most of the artifacts

git-svn-id: http://svn.voria.com/code@361 1f10aa63-cdf2-0310-b900-c93c546f37ac

diff --git a/synfig-core/trunk/src/modules/mod_gradient/lineargradient.cpp b/synfig-core/trunk/src/modules/mod_gradient/lineargradient.cpp
index 27364d7..8ee8920 100644 (file)
--- a/synfig-core/trunk/src/modules/mod_gradient/lineargradient.cpp
+++ b/synfig-core/trunk/src/modules/mod_gradient/lineargradient.cpp
@@ -95,14 +95,20 @@ LinearGradient::color_func(const Point &point, float supersample)const
        {
                if(dist+supersample*0.5>1.0)
                {
-                       Color pool(gradient(dist,supersample*0.5).premult_alpha()*(1.0-(dist-supersample*0.5)));
-                       pool+=gradient((dist+supersample*0.5)-1.0,supersample*0.5).premult_alpha()*((dist+supersample*0.5)-1.0);
+                       float  left(supersample*0.5-(dist-1.0));
+                       float right(supersample*0.5+(dist-1.0));
+                       Color pool(gradient(1.0-(left*0.5),left).premult_alpha()*left/supersample);
+                       if (zigzag) pool+=gradient(1.0-right*0.5,right).premult_alpha()*right/supersample;
+                       else            pool+=gradient(right*0.5,right).premult_alpha()*right/supersample;
                        return pool.demult_alpha();
                }
                if(dist-supersample*0.5<0.0)
                {
-                       Color pool(gradient(dist,supersample*0.5).premult_alpha()*(dist+supersample*0.5));
-                       pool+=gradient(1.0-(dist-supersample*0.5),supersample*0.5).premult_alpha()*(-(dist-supersample*0.5));
+                       float  left(supersample*0.5-dist);
+                       float right(supersample*0.5+dist);
+                       Color pool(gradient(right*0.5,right).premult_alpha()*right/supersample);
+                       if (zigzag) pool+=gradient(left*0.5,left).premult_alpha()*left/supersample;
+                       else            pool+=gradient(1.0-left*0.5,left).premult_alpha()*left/supersample;
                        return pool.demult_alpha();
                }
        }