[gimp] app: add gimp_display_shell_has_filter()

[Michael Natterer <mitch src gnome org>]

commit 1b9a8b71ba5ea16543379a9f12c71121fa431f3b
Author: Michael Natterer <mitch gimp org>
Date:   Mon Jun 1 08:16:12 2015 +0200

    app: add gimp_display_shell_has_filter()
    
    which checks if there are any filters active on the display.

 app/display/gimpdisplayshell-filter.c |    8 ++++++++
 app/display/gimpdisplayshell-filter.h |   11 +++++++----
 2 files changed, 15 insertions(+), 4 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-filter.c b/app/display/gimpdisplayshell-filter.c
index 47f7015..773ce75 100644
--- a/app/display/gimpdisplayshell-filter.c
+++ b/app/display/gimpdisplayshell-filter.c
@@ -74,6 +74,14 @@ gimp_display_shell_filter_set (GimpDisplayShell      *shell,
   gimp_display_shell_filter_changed (NULL, shell);
 }
 
+gboolean
+gimp_display_shell_has_filter (GimpDisplayShell *shell)
+{
+  g_return_val_if_fail (GIMP_IS_DISPLAY_SHELL (shell), FALSE);
+
+  return shell->filter_stack && shell->filter_stack->filters;
+}
+
 GimpColorDisplayStack *
 gimp_display_shell_filter_new (GimpDisplayShell *shell,
                                GimpColorConfig  *config)
diff --git a/app/display/gimpdisplayshell-filter.h b/app/display/gimpdisplayshell-filter.h
index 20b8947..af22c3d 100644
--- a/app/display/gimpdisplayshell-filter.h
+++ b/app/display/gimpdisplayshell-filter.h
@@ -19,11 +19,14 @@
 #define __GIMP_DISPLAY_SHELL_FILTER_H__
 
 
-void   gimp_display_shell_filter_set (GimpDisplayShell      *shell,
-                                      GimpColorDisplayStack *stack);
+void       gimp_display_shell_filter_set (GimpDisplayShell      *shell,
+                                          GimpColorDisplayStack *stack);
 
-GimpColorDisplayStack * gimp_display_shell_filter_new (GimpDisplayShell *shell,
-                                                       GimpColorConfig  *config);
+gboolean   gimp_display_shell_has_filter (GimpDisplayShell      *shell);
+
+GimpColorDisplayStack *
+           gimp_display_shell_filter_new (GimpDisplayShell      *shell,
+                                          GimpColorConfig       *config);
 
 
 #endif /* __GIMP_DISPLAY_SHELL_FILTER_H__ */