[gimp] app: undraw the old canvas items only before drawing new ones

[Michael Natterer <mitch src gnome org>]

commit cbaf997ae22902319958275240db5c386fe3d8f1
Author: Michael Natterer <mitch gimp org>
Date:   Fri Sep 24 23:25:19 2010 +0200

    app: undraw the old canvas items only before drawing new ones
    
    or when the draw tool is really stopped. This seems to get rid of any
    remaining flickering and also reduces expose events. Also get rid of
    the "is_drawn" state and API because they make no sense any longer.

 app/tools/gimpdrawtool.c |   26 +++++---------------------
 app/tools/gimpdrawtool.h |    3 ---
 2 files changed, 5 insertions(+), 24 deletions(-)
---
diff --git a/app/tools/gimpdrawtool.c b/app/tools/gimpdrawtool.c
index 8eb2311..3da6930 100644
--- a/app/tools/gimpdrawtool.c
+++ b/app/tools/gimpdrawtool.c
@@ -105,9 +105,8 @@ static void
 gimp_draw_tool_init (GimpDrawTool *draw_tool)
 {
   draw_tool->display      = NULL;
-
   draw_tool->paused_count = 0;
-  draw_tool->is_drawn     = FALSE;
+  draw_tool->items        = NULL;
 }
 
 static void
@@ -201,29 +200,24 @@ gimp_draw_tool_clear_items (GimpDrawTool *draw_tool)
 static void
 gimp_draw_tool_draw (GimpDrawTool *draw_tool)
 {
-  if (draw_tool->paused_count == 0 &&
-      draw_tool->display)
+  if (draw_tool->display && draw_tool->paused_count == 0)
     {
+      gimp_draw_tool_invalidate_items (draw_tool);
       gimp_draw_tool_clear_items (draw_tool);
 
       GIMP_DRAW_TOOL_GET_CLASS (draw_tool)->draw (draw_tool);
 
       gimp_draw_tool_invalidate_items (draw_tool);
-
-      draw_tool->is_drawn = TRUE;
     }
 }
 
 static void
 gimp_draw_tool_undraw (GimpDrawTool *draw_tool)
 {
-  if (draw_tool->paused_count == 0 &&
-      draw_tool->display)
+  if (draw_tool->display)
     {
       gimp_draw_tool_invalidate_items (draw_tool);
       gimp_draw_tool_clear_items (draw_tool);
-
-      draw_tool->is_drawn = FALSE;
     }
 }
 
@@ -270,8 +264,6 @@ gimp_draw_tool_pause (GimpDrawTool *draw_tool)
 {
   g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));
 
-  gimp_draw_tool_undraw (draw_tool);
-
   draw_tool->paused_count++;
 }
 
@@ -286,14 +278,6 @@ gimp_draw_tool_resume (GimpDrawTool *draw_tool)
   gimp_draw_tool_draw (draw_tool);
 }
 
-gboolean
-gimp_draw_tool_is_drawn (GimpDrawTool *draw_tool)
-{
-  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);
-
-  return draw_tool->is_drawn;
-}
-
 void
 gimp_draw_tool_draw_items (GimpDrawTool *draw_tool,
                            cairo_t      *cr)
@@ -306,7 +290,7 @@ gimp_draw_tool_draw_items (GimpDrawTool *draw_tool,
   g_return_if_fail (cr != NULL);
 
   if (! gimp_draw_tool_is_active (draw_tool) ||
-      ! gimp_draw_tool_is_drawn (draw_tool))
+      draw_tool->paused_count > 0)
     return;
 
   shell  = gimp_display_get_shell (draw_tool->display);
diff --git a/app/tools/gimpdrawtool.h b/app/tools/gimpdrawtool.h
index 9974638..e10775b 100644
--- a/app/tools/gimpdrawtool.h
+++ b/app/tools/gimpdrawtool.h
@@ -41,7 +41,6 @@ struct _GimpDrawTool
                                  */
 
   gint            paused_count; /*  count to keep track of multiple pauses  */
-  gboolean        is_drawn;     /*  is the stuff we draw currently visible  */
 
   GList          *items;
 };
@@ -67,8 +66,6 @@ gboolean   gimp_draw_tool_is_active                (GimpDrawTool     *draw_tool)
 void       gimp_draw_tool_pause                    (GimpDrawTool     *draw_tool);
 void       gimp_draw_tool_resume                   (GimpDrawTool     *draw_tool);
 
-gboolean   gimp_draw_tool_is_drawn                 (GimpDrawTool     *draw_tool);
-
 void       gimp_draw_tool_draw_items               (GimpDrawTool     *draw_tool,
                                                     cairo_t          *cr);