Add input and bounding shapes support (#2742)

Basic idea: if the window has a shape, set the parent container shape as
the union of the window shape and the shape of the frame borders.

Co-authored-by: Uli Schlachter <psychon@znc.in>

include/data.h

@@ -484,6 +484,11 @@ struct Window {
     /* aspect ratio from WM_NORMAL_HINTS (MPlayer uses this for example) */
     double min_aspect_ratio;
     double max_aspect_ratio;
+
+    /** The window has a nonrectangular shape. */
+    bool shaped;
+    /** The window has a nonrectangular input shape. */
+    bool input_shaped;
 };
 
 /**

include/handlers.h

@@ -16,6 +16,7 @@
 
 extern int randr_base;
 extern int xkb_base;
+extern int shape_base;
 
 /**
  * Adds the given sequence to the list of events which are ignored.

include/i3.h

@@ -14,6 +14,7 @@
 #include <sys/time.h>
 #include <sys/resource.h>
 
+#include <xcb/shape.h>
 #include <xcb/xcb_keysyms.h>
 #include <xcb/xkb.h>
 
@@ -70,7 +71,7 @@ extern uint8_t root_depth;
 extern xcb_visualid_t visual_id;
 extern xcb_colormap_t colormap;
 
-extern bool xcursor_supported, xkb_supported;
+extern bool xcursor_supported, xkb_supported, shape_supported;
 extern xcb_window_t root;
 extern struct ev_loop *main_loop;
 extern bool only_check_config;

include/x.h

@@ -137,3 +137,8 @@ void x_set_warp_to(Rect *rect);
  *
  */
 void x_mask_event_mask(uint32_t mask);
+
+/**
+ * Enables or disables nonrectangular shape of the container frame.
+ */
+void x_set_shape(Con *con, xcb_shape_sk_t kind, bool enable);