[gimp] app: reduce redraws on statusbar

[Jehan <jehanp src gnome org>]

commit b4099de8cd22ef474ed76d5413b604bb7a046569
Author: Lukas Oberhuber <lukaso gmail com>
Date:   Wed Jan 19 19:46:34 2022 +0000

    app: reduce redraws on statusbar
    
    This change reduces redraws due to spurious status updates.
    Before this change, the status would be unset, then set again to the
    same value it was previously. Each turn around setting and unsetting
    causes a redraw.
    
    On macOS this redraw causes a full screen redraw. With this
    optimization, when the status message is unchanged, no redraw occurs.
    
    This is because `gimp_tool_push_status` checks to see if the message
    has changed.

 app/tools/gimppainttool.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
---
diff --git a/app/tools/gimppainttool.c b/app/tools/gimppainttool.c
index cfa01541f3..52bd340553 100644
--- a/app/tools/gimppainttool.c
+++ b/app/tools/gimppainttool.c
@@ -607,6 +607,7 @@ gimp_paint_tool_oper_update (GimpTool         *tool,
   GimpDisplayShell *shell         = gimp_display_get_shell (display);
   GimpImage        *image         = gimp_display_get_image (display);
   GList            *drawables;
+  gchar            *status        = NULL;
 
   if (gimp_color_tool_is_enabled (GIMP_COLOR_TOOL (tool)))
     {
@@ -621,8 +622,6 @@ gimp_paint_tool_oper_update (GimpTool         *tool,
       draw_tool->display != display)
     gimp_draw_tool_stop (draw_tool);
 
-  gimp_tool_pop_status (tool, display);
-
   if (tool->display            &&
       tool->display != display &&
       gimp_display_get_image (tool->display) == image)
@@ -642,7 +641,6 @@ gimp_paint_tool_oper_update (GimpTool         *tool,
        (g_list_length (drawables) > 1 && paint_tool->can_multi_paint)) &&
       proximity)
     {
-      gchar    *status;
       gboolean  constrain_mask = gimp_get_constrain_behavior_mask ();
 
       core->cur_coords = *coords;
@@ -703,8 +701,6 @@ gimp_paint_tool_oper_update (GimpTool         *tool,
                                            NULL);
           paint_tool->draw_line = FALSE;
         }
-      gimp_tool_push_status (tool, display, "%s", status);
-      g_free (status);
 
       paint_tool->cursor_x = core->cur_coords.x;
       paint_tool->cursor_y = core->cur_coords.y;
@@ -717,6 +713,16 @@ gimp_paint_tool_oper_update (GimpTool         *tool,
       gimp_draw_tool_stop (draw_tool);
     }
 
+  if (status != NULL)
+    {
+      gimp_tool_push_status (tool, display, "%s", status);
+      g_free (status);
+    }
+  else
+    {
+      gimp_tool_pop_status (tool, display);
+    }
+
   GIMP_TOOL_CLASS (parent_class)->oper_update (tool, coords, state, proximity,
                                                display);