From cbaf997ae22902319958275240db5c386fe3d8f1 Mon Sep 17 00:00:00 2001
From: Michael Natterer <mitch@gimp.org>
Date: Fri, 24 Sep 2010 23:25:19 +0200
Subject: [PATCH] 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 8eb23116c0..3da6930582 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 99746380d9..e10775b57f 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);