Add keepBorder <theme> option and enable it by default

With the new keepBorder option enabled, the
ToggleDecorations action now has 3 states:

- the first time only disables the titlebar
- the second time disables the whole SSD
- the third time enables the whole SSD again

When the keepBorder action is disabled, the old 2-state
behavior is restored, e.g. the ToggleDecorations action
only toggles between on and off.

Fixes #813

include/config/rcxml.h

@@ -48,6 +48,7 @@ struct rcxml {
 	/* theme */
 	char *theme_name;
 	int corner_radius;
+	bool ssd_keep_border;
 	struct font font_activewindow;
 	struct font font_menuitem;
 	struct font font_osd;

include/ssd-internal.h

@@ -54,7 +54,8 @@ struct ssd {
 
 	/* The top of the view, containing buttons, title, .. */
 	struct {
-		/* struct wlr_scene_tree *tree;      unused for now */
+		int height;
+		struct wlr_scene_tree *tree;
 		struct ssd_sub_tree active;
 		struct ssd_sub_tree inactive;
 	} titlebar;

include/ssd.h

@@ -63,6 +63,8 @@ void ssd_set_active(struct ssd *ssd, bool active);
 void ssd_update_title(struct ssd *ssd);
 void ssd_update_geometry(struct ssd *ssd);
 void ssd_destroy(struct ssd *ssd);
+bool ssd_titlebar_is_hidden(struct ssd *ssd);
+void ssd_titlebar_hide(struct ssd *ssd);
 
 void ssd_enable_keybind_inhibit_indicator(struct ssd *ssd, bool enable);
 

include/view.h

@@ -89,6 +89,7 @@ struct view {
 	bool mapped;
 	bool been_mapped;
 	bool ssd_enabled;
+	bool ssd_titlebar_hidden;
 	enum ssd_preference ssd_preference;
 	bool minimized;
 	bool maximized;