Patch by Johan to fix crashing by undefined path parameters in 4 LPEs

[inkscape.git] / src / live_effects / lpe-patternalongpath.cpp

diff --git a/src/live_effects/lpe-patternalongpath.cpp b/src/live_effects/lpe-patternalongpath.cpp
index 29c5517bfe4485814fc4a2fd7704e648035a2fa4..45b2b67b4505630f1cec7ac4cf49c3d8a9018f0c 100644 (file)
--- a/src/live_effects/lpe-patternalongpath.cpp
+++ b/src/live_effects/lpe-patternalongpath.cpp
@@ -33,7 +33,7 @@ B is a map t --> B(t) = ( a(t), b(t) ).
 The first step is to re-parametrize B by its arc length: this is the parametrization in which a point p on B is located by its distance s from start. One obtains a new map s --> U(s) = (a'(s),b'(s)), that still describes the same path B, but where the distance along B from start to
 U(s) is s itself.
 
-We also need a unit normal to the path. This can be obtained by computing a unit tangent vector, and rotate it by 90°. Call this normal vector N(s).
+We also need a unit normal to the path. This can be obtained by computing a unit tangent vector, and rotate it by 90�. Call this normal vector N(s).
 
 The basic deformation associated to B is then given by:
 
@@ -104,6 +104,11 @@ LPEPatternAlongPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > con
 {
     using namespace Geom;
 
+    // Don't allow empty path parameter:
+    if ( pattern.get_pathvector().empty() ) {
+        return pwd2_in;
+    }
+
 /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
     Piecewise<D2<SBasis> > output;
     std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > pre_output;