From c0268de2f3b25b925827050b2f3ce35be4ce6b1e Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 16 Nov 2006 06:37:55 +0000
Subject: [PATCH] improve merging of snips when a style change is applied to a
 range (as by the syntax colorer)

svn: r4871
---
 src/mred/wxme/wx_mpriv.cxx | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/mred/wxme/wx_mpriv.cxx b/src/mred/wxme/wx_mpriv.cxx
index a92c03247c..9de80249d1 100644
--- a/src/mred/wxme/wx_mpriv.cxx
+++ b/src/mred/wxme/wx_mpriv.cxx
@@ -235,7 +235,7 @@ void wxMediaEdit::_ChangeStyle(long start, long end,
   wxSnip *gsnip, *startSnip, *endSnip;
   wxStyleChangeRecord *rec;
   wxStyle *style, *style2, *prev_style;
-  long p, prev_style_pos;
+  long p, prev_style_pos, extra_check_pos = 0;
   int something;
 
   if (writeLocked || userLocked)
@@ -317,7 +317,9 @@ void wxMediaEdit::_ChangeStyle(long start, long end,
       gsnip->style = style2;
 
       if (rec && (style != prev_style)) {
-	rec->AddStyleChange(prev_style_pos, p, prev_style);
+        if (prev_style) {
+          rec->AddStyleChange(prev_style_pos, p, prev_style);
+        }
 	prev_style_pos = p;
 	prev_style = style;
       }
@@ -327,6 +329,8 @@ void wxMediaEdit::_ChangeStyle(long start, long end,
       if (maxWidth > 0)
 	gsnip->line->MarkCheckFlow();
 
+      extra_check_pos = p;
+
       something = TRUE;
     } else if (rec && prev_style) {
       rec->AddStyleChange(prev_style_pos, p, prev_style);
@@ -356,7 +360,10 @@ void wxMediaEdit::_ChangeStyle(long start, long end,
       delayedStreak = TRUE;
     
     CheckMergeSnips(start);
-    CheckMergeSnips(end);
+    if (extra_check_pos)
+      CheckMergeSnips(extra_check_pos);
+    if (extra_check_pos != end)
+      CheckMergeSnips(end);
     
     if (!modified && counts_as_mod)
       SetModified(TRUE);