Identify topmost interactive layer surface

examples/layer-shell.c

@@ -36,6 +36,7 @@ static int32_t margin_top = 0;
 static double alpha = 1.0;
 static bool run_display = true;
 static bool animate = false;
+static bool keyboard_interactive = false;
 static double frame = 0;
 static int cur_x = -1, cur_y = -1;
 static int buttons = 0;
@@ -274,7 +275,7 @@ int main(int argc, char **argv) {
 	int32_t margin_right = 0, margin_bottom = 0, margin_left = 0;
 	bool found;
 	int c;
-	while ((c = getopt(argc, argv, "nw:h:o:l:a:x:m:t:")) != -1) {
+	while ((c = getopt(argc, argv, "knw:h:o:l:a:x:m:t:")) != -1) {
 		switch (c) {
 		case 'o':
 			output = atoi(optarg);
@@ -354,6 +355,9 @@ int main(int argc, char **argv) {
 		case 'n':
 			animate = true;
 			break;
+		case 'k':
+			keyboard_interactive = true;
+			break;
 		default:
 			break;
 		}
@@ -407,9 +411,10 @@ int main(int argc, char **argv) {
 	zwlr_layer_surface_v1_set_exclusive_zone(layer_surface, exclusive_zone);
 	zwlr_layer_surface_v1_set_margin(layer_surface,
 			margin_top, margin_right, margin_bottom, margin_left);
+	zwlr_layer_surface_v1_set_keyboard_interactivity(
+			layer_surface, keyboard_interactive);
 	zwlr_layer_surface_v1_add_listener(layer_surface,
-				   &layer_surface_listener, layer_surface);
-	// TODO: interactivity
+			&layer_surface_listener, layer_surface);
 	wl_surface_commit(wl_surface);
 	wl_display_roundtrip(display);
 

rootston/layer_shell.c

@@ -192,6 +192,29 @@ void arrange_layers(struct roots_output *output) {
 	arrange_layer(output->wlr_output,
 			&output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
 			&usable_area, false);
+
+	// Find topmost keyboard interactive layer, if such a layer exists
+	uint32_t layers_above_shell[] = {
+		ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY,
+		ZWLR_LAYER_SHELL_V1_LAYER_TOP,
+	};
+	struct roots_layer_surface *layer, *topmost = NULL;
+	for (size_t i = 0;
+			i < sizeof(layers_above_shell) / sizeof(layers_above_shell[0]);
+			++i) {
+		wl_list_for_each_reverse(layer,
+				&output->layers[layers_above_shell[i]],
+				link) {
+			if (layer->layer_surface->current.keyboard_interactive) {
+				topmost = layer;
+				break;
+			}
+		}
+		if (topmost != NULL) {
+			break;
+		}
+	}
+	wlr_log(L_DEBUG, "topmost interactive layer: %p", topmost);
 }
 
 static void handle_output_destroy(struct wl_listener *listener, void *data) {