[gimp] Bug 668814: Cannot move cursor right in on canvas editor

[Massimo Valentini <mvalentini src gnome org>]

commit b9942804734ded8d068de9026b2e370a638d376e
Author: Massimo Valentini <mvalentini src gnome org>
Date:   Thu Feb 9 12:36:43 2012 +0100

    Bug 668814: Cannot move cursor right in on canvas editor
    
    One possible way to decrease the incompatibilities
    between letter spacing in a tagged gtk_text_buffer
    and in an equivalent pango_layout
    
    Remove also a valgrind reported invalid write in
    gimptextbuffer.c

 app/tools/gimptexttool-editor.c |   17 +++++++++++++++--
 app/widgets/gimptextbuffer.c    |    2 +-
 2 files changed, 16 insertions(+), 3 deletions(-)
---
diff --git a/app/tools/gimptexttool-editor.c b/app/tools/gimptexttool-editor.c
index 25af4c4..bb15762 100644
--- a/app/tools/gimptexttool-editor.c
+++ b/app/tools/gimptexttool-editor.c
@@ -677,16 +677,19 @@ gimp_text_tool_move_cursor (GimpTextTool    *text_tool,
       if (! cancel_selection)
         {
           PangoLayout *layout;
+          const gchar *text;
 
           if (! gimp_text_tool_ensure_layout (text_tool))
             break;
 
           layout = gimp_text_layout_get_pango_layout (text_tool->layout);
+          text = pango_layout_get_text (layout);
 
           while (count != 0)
             {
+              const gunichar word_joiner = 8288; /*g_utf8_get_char(WORD_JOINER);*/
               gint index;
-              gint trailing;
+              gint trailing = 0;
               gint new_index;
 
               index = gimp_text_buffer_get_iter_index (text_tool->buffer,
@@ -694,7 +697,13 @@ gimp_text_tool_move_cursor (GimpTextTool    *text_tool,
 
               if (count > 0)
                 {
-                  pango_layout_move_cursor_visually (layout, TRUE, index, 0, 1,
+                  if (g_utf8_get_char (text + index) == word_joiner)
+                    pango_layout_move_cursor_visually (layout, TRUE, index, 0, 1,
+                                                       &new_index, &trailing);
+                  else
+                    new_index = index;
+
+                  pango_layout_move_cursor_visually (layout, TRUE, new_index, trailing, 1,
                                                      &new_index, &trailing);
                   count--;
                 }
@@ -702,6 +711,10 @@ gimp_text_tool_move_cursor (GimpTextTool    *text_tool,
                 {
                   pango_layout_move_cursor_visually (layout, TRUE, index, 0, -1,
                                                      &new_index, &trailing);
+
+                  if (new_index != -1 && g_utf8_get_char (text + new_index) == word_joiner)
+                    pango_layout_move_cursor_visually (layout, TRUE, new_index, trailing, -1,
+                                                       &new_index, &trailing);
                   count++;
                 }
 
diff --git a/app/widgets/gimptextbuffer.c b/app/widgets/gimptextbuffer.c
index 24eb9cb..6a4cfad 100644
--- a/app/widgets/gimptextbuffer.c
+++ b/app/widgets/gimptextbuffer.c
@@ -1373,7 +1373,7 @@ gimp_text_buffer_get_iter_at_index (GimpTextBuffer *buffer,
 
               if (g_list_find (buffer->kerning_tags, tag))
                 {
-                  index -= WORD_JOINER_LENGTH;
+                  index = MAX (0, index - WORD_JOINER_LENGTH);
 
                   break;
                 }