From 20604a9037ad7c995977b20f9e5f16b4fe10125a Mon Sep 17 00:00:00 2001
From: "Johan B. C. Engelen" <jbc.engelen@swissonline.ch>
Date: Tue, 10 Apr 2012 19:56:29 +0200
Subject: fix potential issue with tangent calculation

(bzr r11211)
---
 src/live_effects/lpe-powerstroke.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'src')

diff --git a/src/live_effects/lpe-powerstroke.cpp b/src/live_effects/lpe-powerstroke.cpp
index 878811275..79997ff94 100644
--- a/src/live_effects/lpe-powerstroke.cpp
+++ b/src/live_effects/lpe-powerstroke.cpp
@@ -239,7 +239,7 @@ std::vector<discontinuity_data> find_discontinuities( Geom::Piecewise<Geom::D2<G
             data.der0 = der[i-1].at1();
             data.der1 = der[i].at0();
             if ( Geom::are_near(data.der0.length(), 0) ) {
-                data.der0 = unitTangentAt(der[i-1], 1, 2);
+                data.der0 = -unitTangentAt(reverse(der[i-1]),0.,2); // == unitTangentAt(der[i-1], 1, 2);
             }
             if ( Geom::are_near(data.der1.length(), 0) ) {
                 data.der1 = unitTangentAt(der[i], 0, 2);
@@ -304,7 +304,7 @@ Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis>
                        A 2Geom method was created to do exactly this :)
                        */
 
-                    Geom::Point tang1 = unitTangentAt(B[prev_i],1);
+                    Geom::Point tang1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1);
                     Geom::Point tang2 = unitTangentAt(B[i],0);
                     boost::optional<Geom::Point> O = intersection_point( B[prev_i].at1(), tang1,
                                                                               B[i].at0(), tang2 );
@@ -326,7 +326,7 @@ Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis>
 /*            case LINEJOIN_NONE: {
                 if ( on_outside ) {
                     // we are on the outside
-                    Geom::Point der1 = unitTangentAt(B[prev_i],1);
+                    Geom::Point der1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1);
                     Geom::Point point_on_path = B[prev_i].at1() - rot90(der1) * cusp.width;
                     pb.lineTo(point_on_path);
                     pb.lineTo(B[i].at0());
@@ -339,7 +339,7 @@ Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis>
                 if (on_outside) {
                     // we are on the outside, do something complicated to make it look good ;)
 
-                    Geom::Point der1 = unitTangentAt(B[prev_i],1);
+                    Geom::Point der1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1);
                     Geom::Point der2 = unitTangentAt(B[i],0);
 
                     Geom::D2<Geom::SBasis> newcurve1 = B[prev_i] * Geom::reflection(rot90(der1), B[prev_i].at1());
@@ -377,7 +377,7 @@ Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis>
                 if (on_outside) {
                     // we are on the outside, do something complicated to make it look good ;)
 
-                    Geom::Point der1 = unitTangentAt(B[prev_i],1);
+                    Geom::Point der1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1);
                     Geom::Point der2 = unitTangentAt(B[i],0);
                     boost::optional<Geom::Point> p = intersection_point( B[prev_i].at1(), der1,
                                                                          B[i].at0(), der2 );
@@ -399,7 +399,7 @@ Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis>
             }
             case LINEJOIN_SPIRO: {
                 if (on_outside) {
-                    Geom::Point tang1 = unitTangentAt(B[prev_i],1);
+                    Geom::Point tang1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1);
                     Geom::Point tang2 = unitTangentAt(B[i],0);
 
                     Geom::Point direction = B[i].at0() - B[prev_i].at1();
-- 
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