Support xwayland window title bar dragging

Makefile

@@ -13,9 +13,11 @@ ASAN_FLAGS = -O0 -fsanitize=address -fno-common -fno-omit-frame-pointer -rdynami
 WP = `pkg-config --variable=pkgdatadir wayland-protocols`
 WS = `pkg-config --variable=wayland_scanner wayland-scanner`
 
+OBJS = main.o xdg.o view.o xwl.o server.o output.o dbg.o deco.o
+
 all: labwc
 
-labwc: xdg-shell-protocol.o main.o xdg.o view.o xwl.o server.o output.o dbg.o
+labwc: xdg-shell-protocol.o $(OBJS)
 	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
 
 xdg-shell-protocol.h:

README.md

@@ -2,8 +2,6 @@
 
 labwc is a wayland compositor based on wlroots
 
-[https://imgur.com/rb2hJh3](https://imgur.com/rb2hJh3)
-
 ## Dependencies
 
 - wlroots
@@ -15,7 +13,6 @@ labwc is a wayland compositor based on wlroots
 Alt+Escape  Exit labwc
 Alt+F2      Cycle between windows
 Alt+F3      Launch dmenu
-Alt+F6      Move window
 Alt+F12     Print all views (helpful if run from X11)
 ```
 
@@ -47,7 +44,7 @@ In terms of size comparison of these two giants, it's worth reflecting on the si
 
 [sway](https://github.com/swaywm/sway) - 37k LOC
 
-[rootston](https://github.com/swaywm/wlroots/tree/master/rootston) - 7k LOC
+[rootston]() - 7k LOC
 
 [openbox](https://github.com/danakj/openbox) - 53k LOC
 

deco.c

@@ -0,0 +1,39 @@
+#include "labwc.h"
+
+struct wlr_box deco_max_extents(struct view *view)
+{
+	struct wlr_box box = {
+		.x = view->x - XWL_WINDOW_BORDER,
+		.y = view->y - XWL_TITLEBAR_HEIGHT - XWL_WINDOW_BORDER,
+		.width = view->surface->current.width + 2 * XWL_WINDOW_BORDER,
+		.height = view->surface->current.height + XWL_TITLEBAR_HEIGHT +
+			  2 * XWL_WINDOW_BORDER,
+	};
+	return box;
+}
+
+struct wlr_box deco_box(struct view *view, enum deco_part deco_part)
+{
+	struct wlr_box box = { .x = 0, .y = 0, .width = 0, .height = 0 };
+	if (!view)
+		return;
+	switch (deco_part) {
+	case LAB_DECO_PART_TOP:
+		box.x = view->x - XWL_WINDOW_BORDER;
+		box.y = view->y - XWL_TITLEBAR_HEIGHT - XWL_WINDOW_BORDER;
+		box.width = view->surface->current.width + 2 * XWL_WINDOW_BORDER;
+		box.height = XWL_TITLEBAR_HEIGHT + XWL_WINDOW_BORDER;
+		break;
+	}
+	return box;
+}
+
+enum deco_part deco_at(struct view *view, double lx, double ly)
+{
+	struct wlr_box box;
+	box = deco_box(view, LAB_DECO_PART_TOP);
+	if (wlr_box_contains_point(&box, lx, ly))
+		return LAB_DECO_PART_TOP;
+	return LAB_DECO_NONE;
+}
+

labwc.h

@@ -33,7 +33,6 @@
 #define XWL_TITLEBAR_HEIGHT (10)
 #define XWL_WINDOW_BORDER (3)
 
-/* For brevity's sake, struct members are annotated where they are used. */
 enum cursor_mode {
 	TINYWL_CURSOR_PASSTHROUGH,
 	TINYWL_CURSOR_MOVE,
@@ -84,6 +83,11 @@ struct output {
 
 enum view_type { LAB_XDG_SHELL_VIEW, LAB_XWAYLAND_VIEW };
 
+enum deco_part {
+	LAB_DECO_NONE,
+	LAB_DECO_PART_TOP
+};
+
 struct view {
 	enum view_type type;
 	struct wl_list link;
@@ -131,6 +135,7 @@ void xwl_surface_destroy(struct wl_listener *listener, void *data);
 void xwl_surface_configure(struct wl_listener *listener, void *data);
 void xwl_surface_new(struct wl_listener *listener, void *data);
 
+bool view_want_deco(struct view *view);
 void view_focus_last_toplevel(struct server *server);
 void focus_view(struct view *view, struct wlr_surface *surface);
 void view_focus_next_toplevel(struct server *server);
@@ -139,7 +144,7 @@ void begin_interactive(struct view *view, enum cursor_mode mode,
 bool is_toplevel(struct view *view);
 struct view *desktop_view_at(struct server *server, double lx, double ly,
 			     struct wlr_surface **surface, double *sx,
-			     double *sy);
+			     double *sy, int *view_area);
 
 /* TODO: try to refactor to remove from header file */
 struct view *first_toplevel(struct server *server);
@@ -157,4 +162,8 @@ void output_frame(struct wl_listener *listener, void *data);
 
 void dbg_show_views(struct server *server);
 
+struct wlr_box deco_max_extents(struct view *view);
+struct wlr_box deco_box(struct view *view, enum deco_part deco_part);
+enum deco_part deco_at(struct view *view, double lx, double ly);
+
 #endif /* LABWC_H */

output.c

@@ -1,9 +1,5 @@
 #include "labwc.h"
 
-/*
- * Used to move all of the data necessary to render a surface from the
- * top-level frame handler to the per-surface render function.
- */
 struct render_data {
 	struct wlr_output *output;
 	struct wlr_renderer *renderer;
@@ -13,32 +9,19 @@ struct render_data {
 
 static void render_decorations(struct wlr_output *output, struct view *view)
 {
-	if (!view->surface)
-		return;
-	if (view->type != LAB_XWAYLAND_VIEW)
-		return;
-	if (!is_toplevel(view))
-		return;
-	if (view->xwayland_surface->override_redirect)
-		return;
-	if (view->xwayland_surface->decorations !=
-	    WLR_XWAYLAND_SURFACE_DECORATIONS_ALL)
+	if (!view_want_deco(view))
 		return;
 
-	struct wlr_box box = {
-		.x = view->x - XWL_WINDOW_BORDER,
-		.y = view->y - XWL_TITLEBAR_HEIGHT - XWL_WINDOW_BORDER,
-		.width = view->surface->current.width + 2 * XWL_WINDOW_BORDER,
-		.height = view->surface->current.height + XWL_TITLEBAR_HEIGHT +
-			  2 * XWL_WINDOW_BORDER,
-	};
-
+	struct wlr_box box = deco_max_extents(view);
 	float matrix[9];
 	wlr_matrix_project_box(matrix, &box, WL_OUTPUT_TRANSFORM_NORMAL, 0,
 			       output->transform_matrix);
-
 	float color[] = { 0.2, 0.2, 0.7, 0.9 };
 	wlr_render_quad_with_matrix(view->server->renderer, color, matrix);
+
+	box = deco_box(view, LAB_DECO_PART_TOP);
+	float color2[] = { 0.7, 0.2, 0.2, 0.9 };
+	wlr_render_rect(view->server->renderer, &box, color2, output->transform_matrix);
 }
 
 static void render_surface(struct wlr_surface *surface, int sx, int sy,

server.c

@@ -252,9 +252,10 @@ static void process_cursor_motion(struct server *server, uint32_t time)
 	double sx, sy;
 	struct wlr_seat *seat = server->seat;
 	struct wlr_surface *surface = NULL;
+	int view_area;
 	struct view *view = desktop_view_at(server, server->cursor->x,
 					    server->cursor->y, &surface, &sx,
-					    &sy);
+					    &sy, &view_area);
 	if (!view) {
 		/* If there's no view under the cursor, set the cursor image to
 		 * a default. This is what makes the cursor image appear when
@@ -262,6 +263,12 @@ static void process_cursor_motion(struct server *server, uint32_t time)
 		wlr_xcursor_manager_set_cursor_image(
 			server->cursor_mgr, "left_ptr", server->cursor);
 	}
+	switch (view_area) {
+	case LAB_DECO_PART_TOP:
+		wlr_xcursor_manager_set_cursor_image(
+			server->cursor_mgr, "left_ptr", server->cursor);
+		break;
+	}
 	if (surface) {
 		bool focus_changed = seat->pointer_state.focused_surface !=
 				     surface;
@@ -332,9 +339,10 @@ void server_cursor_button(struct wl_listener *listener, void *data)
 				       event->button, event->state);
 	double sx, sy;
 	struct wlr_surface *surface;
+	int view_area;
 	struct view *view = desktop_view_at(server, server->cursor->x,
 					    server->cursor->y, &surface, &sx,
-					    &sy);
+					    &sy, &view_area);
 	if (event->state == WLR_BUTTON_RELEASED) {
 		/* If you released any buttons, we exit interactive move/resize
 		 * mode. */
@@ -342,6 +350,11 @@ void server_cursor_button(struct wl_listener *listener, void *data)
 	} else {
 		/* Focus that client if the button was _pressed_ */
 		focus_view(view, surface);
+		switch (view_area) {
+		case LAB_DECO_PART_TOP:
+			begin_interactive(view, TINYWL_CURSOR_MOVE, 0);
+			break;
+		}
 	}
 }
 

view.c

@@ -1,5 +1,21 @@
 #include "labwc.h"
 
+bool view_want_deco(struct view *view)
+{
+	if (!view->surface)
+		return false;
+	if (view->type != LAB_XWAYLAND_VIEW)
+		return false;
+	if (!is_toplevel(view))
+		return false;
+	if (view->xwayland_surface->override_redirect)
+		return false;
+	if (view->xwayland_surface->decorations !=
+	    WLR_XWAYLAND_SURFACE_DECORATIONS_ALL)
+		return false;
+	return true;
+}
+
 static struct view *last_toplevel(struct server *server)
 {
 	struct view *view;
@@ -127,10 +143,6 @@ void begin_interactive(struct view *view, enum cursor_mode mode, uint32_t edges)
 	struct server *server = view->server;
 	struct wlr_surface *focused_surface =
 		server->seat->pointer_state.focused_surface;
-	if (view->surface != focused_surface) {
-		/* Deny move/resize requests from unfocused clients. */
-		return;
-	}
 	server->grabbed_view = view;
 	server->cursor_mode = mode;
 
@@ -216,7 +228,7 @@ static bool view_at(struct view *view, double lx, double ly,
 		break;
 	}
 
-	if (_surface != NULL) {
+	if (_surface) {
 		*sx = _sx;
 		*sy = _sy;
 		*surface = _surface;
@@ -227,16 +239,28 @@ static bool view_at(struct view *view, double lx, double ly,
 
 struct view *desktop_view_at(struct server *server, double lx, double ly,
 			     struct wlr_surface **surface, double *sx,
-			     double *sy)
+			     double *sy, int *view_area)
 {
-	/* This iterates over all of our surfaces and attempts to find one under
-	 * the cursor. This relies on server->views being ordered from
-	 * top-to-bottom. */
+	/*
+	 * This iterates over all of our surfaces and attempts to find one under
+	 * the cursor. It relies on server->views being ordered from
+	 * top-to-bottom.
+	 */
+	struct wlr_box border_box = {
+		.x = 0, .y = 0,
+		.width = 0, .height = 0,
+	};
 	struct view *view;
 	wl_list_for_each (view, &server->views, link) {
-		if (view_at(view, lx, ly, surface, sx, sy)) {
+		if (view_at(view, lx, ly, surface, sx, sy))
+			return view;
+		if (!view_want_deco(view))
+			continue;
+		if (deco_at(view, lx, ly) == LAB_DECO_PART_TOP) {
+			*view_area = LAB_DECO_PART_TOP;
 			return view;
 		}
 	}
 	return NULL;
 }
+