From c2aa64ea2a2778e4b78b16962281d0e0659de249 Mon Sep 17 00:00:00 2001
From: "Johan B. C. Engelen" <jbc.engelen@swissonline.ch>
Date: Sat, 15 May 2010 01:08:45 +0200
Subject: fix bug when forking LPE stack

Fixed bugs:
  - https://launchpad.net/bugs/578969
  - https://launchpad.net/bugs/505400

(bzr r9419)
---
 src/sp-item.cpp | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

(limited to 'src/sp-item.cpp')

diff --git a/src/sp-item.cpp b/src/sp-item.cpp
index c4411e47d..d6f68fc74 100644
--- a/src/sp-item.cpp
+++ b/src/sp-item.cpp
@@ -1377,22 +1377,36 @@ sp_item_adjust_livepatheffect (SPItem *item, Geom::Matrix const &postmul, bool s
 
     SPLPEItem *lpeitem = SP_LPE_ITEM (item);
     if ( sp_lpe_item_has_path_effect(lpeitem) ) {
+        // If one of the path effects is used by 2 or more items, fork it
+        // so that each object has its own independent copy of the effect.
+        // Forking messes up the path effect list, so after each fork,
+        // reload the list and recheck if more forking is required.
+        bool forked = false;
+        do {
+            forked = false;
+            PathEffectList effect_list =  sp_lpe_item_get_effect_list(lpeitem);
+            for (PathEffectList::iterator it = effect_list.begin(); it != effect_list.end(); it++)
+            {
+                LivePathEffectObject *lpeobj = (*it)->lpeobject;
+                if (lpeobj) {
+                    LivePathEffectObject *new_lpeobj = lpeobj->fork_private_if_necessary();
+                    if (new_lpeobj != lpeobj) {
+                        sp_lpe_item_replace_path_effect(lpeitem, lpeobj, new_lpeobj);
+                        forked = true;
+                        break;  // forked, so break the for-loop and recheck
+                    }
+                }
+            }
+        } while (forked);
+
+        // now that all LPEs are forked_if_necessary, we can apply the transform
         PathEffectList effect_list =  sp_lpe_item_get_effect_list(lpeitem);
         for (PathEffectList::iterator it = effect_list.begin(); it != effect_list.end(); it++)
         {
-            // If the path effect is used by 2 or more items, fork it
-            // so that each object has its own independent copy of the effect
             LivePathEffectObject *lpeobj = (*it)->lpeobject;
-            if (lpeobj) {
-                LivePathEffectObject *new_lpeobj = lpeobj->fork_private_if_necessary();
-                if (new_lpeobj != lpeobj) {
-                    sp_lpe_item_replace_path_effect(lpeitem, lpeobj, new_lpeobj);
-                }
-
-                if (lpeobj->get_lpe()) {
-                    Inkscape::LivePathEffect::Effect * effect = lpeobj->get_lpe();
-                    effect->transform_multiply(postmul, set);
-                }
+            if (lpeobj && lpeobj->get_lpe()) {
+                Inkscape::LivePathEffect::Effect * effect = lpeobj->get_lpe();
+                effect->transform_multiply(postmul, set);
             }
         }
     }
-- 
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