layer-shell: introduce wlr_layer_surface_v1_get_exclusive_edge()

include/wlr/types/wlr_layer_shell_v1.h

@@ -13,6 +13,7 @@
 #include <stdint.h>
 #include <wayland-server-core.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/util/edges.h>
 #include "wlr-layer-shell-unstable-v1-protocol.h"
 
 /**
@@ -187,4 +188,11 @@ struct wlr_surface *wlr_layer_surface_v1_popup_surface_at(
 struct wlr_layer_surface_v1 *wlr_layer_surface_v1_from_resource(
 		struct wl_resource *resource);
 
+/**
+ * Get the edge the exclusive zone must be applied to.
+ *
+ * Returns WLR_EDGE_NONE if the exclusive zone is nonpositive or must not be applied.
+ */
+enum wlr_edges wlr_layer_surface_v1_get_exclusive_edge(struct wlr_layer_surface_v1 *surface);
+
 #endif

types/wlr_layer_shell_v1.c

@@ -654,3 +654,33 @@ struct wlr_surface *wlr_layer_surface_v1_popup_surface_at(
 
 	return NULL;
 }
+
+enum wlr_edges wlr_layer_surface_v1_get_exclusive_edge(struct wlr_layer_surface_v1 *surface) {
+	if (surface->current.exclusive_zone <= 0) {
+		return WLR_EDGE_NONE;
+	}
+	uint32_t anchor = surface->current.anchor;
+	if (surface->current.exclusive_edge != 0) {
+		anchor = surface->current.exclusive_edge;
+	}
+	switch (anchor) {
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP:
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT | ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP:
+		return WLR_EDGE_TOP;
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM:
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT | ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM:
+		return WLR_EDGE_BOTTOM;
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT:
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP | ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT:
+		return WLR_EDGE_LEFT;
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT:
+	case ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP | ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT:
+		return WLR_EDGE_RIGHT;
+	default:
+		return WLR_EDGE_NONE;
+	}
+}