patch by KoRi for bug 323594

diff --git a/src/livarot/PathOutline.cpp b/src/livarot/PathOutline.cpp
index cd405d664bbce1de576fa8b279c2938d7344809c..d4fc7eb30253326dcb4d6c2c8b26c3b286a15101 100644 (file)
--- a/src/livarot/PathOutline.cpp
+++ b/src/livarot/PathOutline.cpp
@@ -1167,78 +1167,88 @@ void
 Path::OutlineJoin (Path * dest, Geom::Point pos, Geom::Point stNor, Geom::Point enNor, double width,
                    JoinType join, double miter)
 {
+    /* 
+        Arbitrarily decide if we're on the inside or outside of a half turn.
+        A turn of 180 degrees (line path leaves the node in the same direction as it arrived)
+        is symmetric and has no real inside and outside. However when outlining we shall handle
+        one path as inside and the reverse path as outside. Handling both as inside joins (as
+        was done previously) will cut off round joins. Handling both as outside joins could
+        ideally work because both should fall together, but it seems that this causes many
+        extra nodes (due to rounding errors). Solution: for the 'half turn'-case toggle 
+        inside/outside each time the same node is processed 2 consecutive times.
+    */
+    static bool TurnInside = true;
+    static Geom::Point PrevPos(0, 0);
+    TurnInside ^= PrevPos == pos;
+    PrevPos = pos;
+
        const double angSi = cross (enNor,stNor);
        const double angCo = dot (stNor, enNor);
-       // 1/1000 is very big/ugly, but otherwise it stuffs things up a little...
-       // 1/1000 est tres grossier, mais sinon ca merde tout azimut
-       if ((width >= 0 && angSi > -0.001)
-           || (width < 0 && angSi < 0.001)) {
-               if (angCo > 0.999) {
-                       // straight ahead
-                       // tout droit
-               } else if (angCo < -0.999) {
-                       // half turn
-                       // demit-tour
-                       dest->LineTo (pos + width*enNor);
-               } else {
-                       dest->LineTo (pos);
-                       dest->LineTo (pos + width*enNor);
-               }
-       } else {
-               if (join == join_round) {
-                       // Use the ends of the cubic: approximate the arc at the
-                       // point where .., and support better the rounding of
-                       // coordinates of the end points.
-
-                       // utiliser des bouts de cubique: approximation de l'arc (au point ou on en est...), et supporte mieux
-                       // l'arrondi des coordonnees des extremites
-                       /* double   angle=acos(angCo);
-                          if ( angCo >= 0 ) {
-                          Geom::Point   stTgt,enTgt;
-                          RotCCWTo(stNor,stTgt);
-                          RotCCWTo(enNor,enTgt);
-                          dest->CubicTo(pos.x+width*enNor.x,pos.y+width*enNor.y,
-                          angle*width*stTgt.x,angle*width*stTgt.y,
-                          angle*width*enTgt.x,angle*width*enTgt.y);
-                          } else {
-                          Geom::Point   biNor;
-                          Geom::Point   stTgt,enTgt,biTgt;
-                          biNor.x=stNor.x+enNor.x;
-                          biNor.y=stNor.y+enNor.y;
-                          double  biL=sqrt(biNor.x*biNor.x+biNor.y*biNor.y);
-                          biNor.x/=biL;
-                          biNor.y/=biL;
-                          RotCCWTo(stNor,stTgt);
-                          RotCCWTo(enNor,enTgt);
-                          RotCCWTo(biNor,biTgt);
-                          dest->CubicTo(pos.x+width*biNor.x,pos.y+width*biNor.y,
-                          angle*width*stTgt.x,angle*width*stTgt.y,
-                          angle*width*biTgt.x,angle*width*biTgt.y);
-                          dest->CubicTo(pos.x+width*enNor.x,pos.y+width*enNor.y,
-                          angle*width*biTgt.x,angle*width*biTgt.y,
-                          angle*width*enTgt.x,angle*width*enTgt.y);
-                          }*/
-                       if (width > 0) {
-                               dest->ArcTo (pos + width*enNor,
-                                                        1.0001 * width, 1.0001 * width, 0.0, false, true);
-                       } else {
-                               dest->ArcTo (pos + width*enNor,
-                                                        -1.0001 * width, -1.0001 * width, 0.0, false,
-                                                        false);
-                       }
-               } else if (join == join_pointy) {
-                       Geom::Point const biss = unit_vector(Geom::rot90( stNor - enNor ));
-                       double c2 = Geom::dot (biss, enNor);
-                       double l = width / c2;
-                       if ( fabs(l) > miter) {
-                               dest->LineTo (pos + width*enNor);
-                       } else {
-                               dest->LineTo (pos+l*biss);
-                               dest->LineTo (pos+width*enNor);
-                       }
-               } else {
-                       dest->LineTo (pos + width*enNor);
-               }
+
+    if (angSi == 0 && angCo > 0) { // The join is straight -> nothing to do.
+    } else {
+        if ((angSi > 0 && width >= 0) 
+            || (angSi < 0 && width < 0)) { // This is an inside join -> join is independent of chosen JoinType.
+            dest->LineTo (pos);
+            dest->LineTo (pos + width*enNor);
+        } else if (angSi == 0 && TurnInside) { // Half turn (180 degrees) ... inside (see above).
+            dest->LineTo (pos + width*enNor);
+        } else { // This is an outside join -> chosen JoinType should be applied.
+            if (join == join_round) {
+                // Use the ends of the cubic: approximate the arc at the
+                // point where .., and support better the rounding of
+                // coordinates of the end points.
+
+                // utiliser des bouts de cubique: approximation de l'arc (au point ou on en est...), et supporte mieux
+                // l'arrondi des coordonnees des extremites
+                /* double   angle=acos(angCo);
+                   if ( angCo >= 0 ) {
+                   Geom::Point   stTgt,enTgt;
+                   RotCCWTo(stNor,stTgt);
+                   RotCCWTo(enNor,enTgt);
+                   dest->CubicTo(pos.x+width*enNor.x,pos.y+width*enNor.y,
+                   angle*width*stTgt.x,angle*width*stTgt.y,
+                   angle*width*enTgt.x,angle*width*enTgt.y);
+                   } else {
+                   Geom::Point   biNor;
+                   Geom::Point   stTgt,enTgt,biTgt;
+                   biNor.x=stNor.x+enNor.x;
+                   biNor.y=stNor.y+enNor.y;
+                   double  biL=sqrt(biNor.x*biNor.x+biNor.y*biNor.y);
+                   biNor.x/=biL;
+                   biNor.y/=biL;
+                   RotCCWTo(stNor,stTgt);
+                   RotCCWTo(enNor,enTgt);
+                   RotCCWTo(biNor,biTgt);
+                   dest->CubicTo(pos.x+width*biNor.x,pos.y+width*biNor.y,
+                   angle*width*stTgt.x,angle*width*stTgt.y,
+                   angle*width*biTgt.x,angle*width*biTgt.y);
+                   dest->CubicTo(pos.x+width*enNor.x,pos.y+width*enNor.y,
+                   angle*width*biTgt.x,angle*width*biTgt.y,
+                   angle*width*enTgt.x,angle*width*enTgt.y);
+                   }*/
+                if (width > 0) {
+                    dest->ArcTo (pos + width*enNor,
+                                 1.0001 * width, 1.0001 * width, 0.0, false, true);
+                } else {
+                    dest->ArcTo (pos + width*enNor,
+                                 -1.0001 * width, -1.0001 * width, 0.0, false,
+                                 false);
+                }
+            } else if (join == join_pointy) {
+                Geom::Point const biss = unit_vector(Geom::rot90( stNor - enNor ));
+                double c2 = Geom::dot (biss, enNor);
+                double l = width / c2;
+                if ( fabs(l) > miter) {
+                    dest->LineTo (pos + width*enNor);
+                } else {
+                    dest->LineTo (pos+l*biss);
+                    dest->LineTo (pos+width*enNor);
+                }
+            } else { // Bevel join
+                dest->LineTo (pos + width*enNor);
+            }
+        }
        }
 }