From 59291ede879e339ac40c3dec0a16ddfa8de486b7 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Tue, 16 Sep 2014 12:42:39 -0400
Subject: [PATCH] add a focus handling callback so that all button press events
 on CairoWidgets will cause a focus reset.

Conflicts:
	libs/gtkmm2ext/cairo_widget.cc
	libs/gtkmm2ext/gtkmm2ext/cairo_widget.h
---
 libs/gtkmm2ext/cairo_widget.cc          | 17 +++++++++++++++++
 libs/gtkmm2ext/gtkmm2ext/cairo_widget.h | 21 +++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/libs/gtkmm2ext/cairo_widget.cc b/libs/gtkmm2ext/cairo_widget.cc
index d600052bad..0b7fdad306 100644
--- a/libs/gtkmm2ext/cairo_widget.cc
+++ b/libs/gtkmm2ext/cairo_widget.cc
@@ -24,6 +24,10 @@
 
 static const char* has_cairo_widget_background_info = "has_cairo_widget_background_info";
 
+
+static void noop() { }
+sigc::slot<void> CairoWidget::focus_handler (sigc::ptr_fun (noop));
+
 CairoWidget::CairoWidget ()
 	: _active_state (Gtkmm2ext::Off)
 	, _visual_state (Gtkmm2ext::NoVisualState)
@@ -38,6 +42,13 @@ CairoWidget::~CairoWidget ()
 {
 }
 
+bool
+CairoWidget::on_button_press_event (GdkEventButton*)
+{
+	focus_handler();
+	return false;
+}
+
 bool
 CairoWidget::on_expose_event (GdkEventExpose *ev)
 {
@@ -194,3 +205,9 @@ CairoWidget::provide_background_for_cairo_widget (Gtk::Widget& w, const Gdk::Col
 
 	g_object_set_data (G_OBJECT(w.gobj()), has_cairo_widget_background_info, (void*) 0xfeedface);
 }
+
+void
+CairoWidget::set_focus_handler (sigc::slot<void> s)
+{
+	focus_handler = s;
+}
diff --git a/libs/gtkmm2ext/gtkmm2ext/cairo_widget.h b/libs/gtkmm2ext/gtkmm2ext/cairo_widget.h
index 35e353054a..a82c12fd70 100644
--- a/libs/gtkmm2ext/gtkmm2ext/cairo_widget.h
+++ b/libs/gtkmm2ext/gtkmm2ext/cairo_widget.h
@@ -69,11 +69,30 @@ public:
 
 	virtual void render (cairo_t *, cairo_rectangle_t*) = 0;
 
+	/* set_focus_handler() will cause all button-press events on any
+	   CairoWidget to invoke this slot/functor/function/method/callback.
+	   
+	   We do this because in general, CairoWidgets do not grab
+	   keyboard focus, but a button press on them should
+	   clear focus from any active text entry.
+
+	   This is global to all CairoWidgets and derived types.
+
+	   However, derived types can override the behaviour by defining their
+	   own on_button_press_event() handler which returns true under all
+	   conditions (which will block this handler from being called). If 
+	   they wish to invoke any existing focus handler from their own
+	   button press handler, they can just use: focus_handler();
+	*/
+	static void set_focus_handler (sigc::slot<void>);
+
 protected:
 	/** Render the widget to the given Cairo context */
 	virtual bool on_expose_event (GdkEventExpose *);
 	void on_size_allocate (Gtk::Allocation &);
 	void on_state_changed (Gtk::StateType);
+	bool on_button_press_event (GdkEventButton*);
+
 	Gdk::Color get_parent_bg ();
 	
 	/* this is an additional virtual "on_..." method. Glibmm does not
@@ -87,6 +106,8 @@ protected:
 	bool                   _need_bg;
     GdkEventExpose*        _current_event_expose; // Valid only when on_expose_event
 
+	static sigc::slot<void> focus_handler;
+
   private:
 	Glib::SignalProxyProperty _name_proxy;
 };