kc3-lang/ftgl

diff --git a/src/FTContour.cpp b/src/FTContour.cpp
index 2717beb..c4a04af 100644
--- a/src/FTContour.cpp
+++ b/src/FTContour.cpp
@@ -228,6 +228,8 @@ FTContour::FTContour(FT_Vector* contour, char* tags, unsigned int n)
 
 void FTContour::buildFrontOutset(float outset)
 {
+    frontPointList.clear();
+
     for(size_t i = 0; i < PointCount(); ++i)
     {
         AddFrontPoint(Point(i) + Outset(i) * outset);
@@ -237,6 +239,8 @@ void FTContour::buildFrontOutset(float outset)
 
 void FTContour::buildBackOutset(float outset)
 {
+    backPointList.clear();
+
     for(size_t i = 0; i < PointCount(); ++i)
     {
         AddBackPoint(Point(i) + Outset(i) * outset);