Fix 1792063: problem with curve gradients when a vertex has split tangents which...

git-svn-id: http://svn.voria.com/code@656 1f10aa63-cdf2-0310-b900-c93c546f37ac

diff --git a/synfig-core/trunk/src/modules/mod_gradient/curvegradient.cpp b/synfig-core/trunk/src/modules/mod_gradient/curvegradient.cpp
index d76d76d..508a464 100644 (file)
--- a/synfig-core/trunk/src/modules/mod_gradient/curvegradient.cpp
+++ b/synfig-core/trunk/src/modules/mod_gradient/curvegradient.cpp
@@ -237,6 +237,7 @@ CurveGradient::color_func(const Point &point_, int quality, float supersample)co
        Real dist;
 
        float perp_dist;
+       bool edge_case = false;
 
        if(bline.size()==0)
                return Color::alpha();
@@ -306,6 +307,31 @@ CurveGradient::color_func(const Point &point_, int quality, float supersample)co
                p1=curve(t);                     // the closest point on the curve
                tangent=deriv(t).norm(); // the unit tangent at that point
 
+               // if the point we're nearest to is at either end of the
+               // bline, our distance from the curve is the distance from the
+               // point on the curve.  we need to know which side of the
+               // curve we're on, so find the average of the two tangents at
+               // this point
+               if (t<0.00001 || t>0.99999)
+               {
+                       if (t<0.5)
+                       {
+                               if (iter->get_split_tangent_flag())
+                               {
+                                       tangent=(iter->get_tangent1().norm()+tangent).norm();
+                                       edge_case=true;
+                               }
+                       }
+                       else
+                       {
+                               if (next->get_split_tangent_flag())
+                               {
+                                       tangent=(next->get_tangent2().norm()+tangent).norm();
+                                       edge_case=true;
+                               }
+                       }
+               }
+
                if(perpendicular)
                {
                        tangent*=curve_length_;
@@ -340,7 +366,15 @@ CurveGradient::color_func(const Point &point_, int quality, float supersample)co
        }
        else                                            // not perpendicular
        {
-               diff=tangent.perp()*thickness*width;
+               if (edge_case)
+               {
+                       diff=(p1-(point_-offset));
+                       if(diff*tangent.perp()<0) diff=-diff;
+                       diff=diff.norm()*thickness*width;
+               }
+               else
+                       diff=tangent.perp()*thickness*width;
+
                p1-=diff*0.5;
                const Real mag(diff.inv_mag());
                supersample=supersample*mag;