Add cage clone mode

The main window will be restricted to the smallest dimensions of all possible screens

cage.1.scd

@@ -16,6 +16,9 @@ activities outside the scope of the running application are prevented.
 
 # OPTIONS
 
+*-c*
+	Enable clone mode for all attached screens
+
 *-d*
 	Don't draw client side decorations when possible.
 

cage.c

@@ -241,6 +241,7 @@ usage(FILE *file, const char *cage)
 	fprintf(file,
 		"Usage: %s [OPTIONS] [--] [APPLICATION...]\n"
 		"\n"
+		" -c\t Enable clone mode for all attached screens\n"
 		" -d\t Don't draw client side decorations, when possible\n"
 		" -D\t Enable debug logging\n"
 		" -h\t Display this help message\n"
@@ -257,8 +258,11 @@ static bool
 parse_args(struct cg_server *server, int argc, char *argv[])
 {
 	int c;
-	while ((c = getopt(argc, argv, "dDhm:sv")) != -1) {
+	while ((c = getopt(argc, argv, "cdDhm:sv")) != -1) {
 		switch (c) {
+		case 'c':
+			server->clone_mode = true;
+			break;
 		case 'd':
 			server->xdg_decoration = true;
 			break;

output.c

@@ -66,6 +66,13 @@ update_output_manager_config(struct cg_server *server)
 	}
 
 	wlr_output_manager_v1_set_configuration(server->output_manager_v1, config);
+
+	if (server->clone_mode) {
+		struct wlr_box confine_box;
+		seat_get_clone_confines(server, &confine_box);
+		server->seat->clone_confine_box = confine_box;
+	}
+
 }
 
 static inline void
@@ -110,7 +117,11 @@ output_enable(struct cg_output *output)
 	wlr_output_state_set_enabled(&state, true);
 
 	if (wlr_output_commit_state(wlr_output, &state)) {
-		output_layout_add_auto(output);
+		if (output->server->clone_mode) {
+			output_layout_add(output, 0, 0);
+		} else {
+			output_layout_add_auto(output);
+		}
 	}
 
 	update_output_manager_config(output->server);
@@ -313,7 +324,11 @@ handle_new_output(struct wl_listener *listener, void *data)
 
 	wlr_log(WLR_DEBUG, "Enabling new output %s", wlr_output->name);
 	if (wlr_output_commit_state(wlr_output, &state)) {
-		output_layout_add_auto(output);
+		if (output->server->clone_mode) {
+			output_layout_add(output, 0, 0);
+		} else {
+			output_layout_add_auto(output);
+		}
 	}
 
 	view_position_all(output->server);

seat.c

@@ -626,6 +626,7 @@ process_cursor_motion(struct cg_seat *seat, uint32_t time_msec, double dx, doubl
 	struct wlr_surface *surface = NULL;
 
 	struct cg_view *view = desktop_view_at(seat->server, seat->cursor->x, seat->cursor->y, &surface, &sx, &sy);
+
 	if (!view) {
 		wlr_seat_pointer_clear_focus(wlr_seat);
 	} else {
@@ -669,9 +670,23 @@ handle_cursor_motion_relative(struct wl_listener *listener, void *data)
 {
 	struct cg_seat *seat = wl_container_of(listener, seat, cursor_motion_relative);
 	struct wlr_pointer_motion_event *event = data;
+	double delta_x = event->delta_x;
+	double delta_y = event->delta_y;
 
-	wlr_cursor_move(seat->cursor, &event->pointer->base, event->delta_x, event->delta_y);
+	if (seat->server->clone_mode) {
-	process_cursor_motion(seat, event->time_msec, event->delta_x, event->delta_y, event->unaccel_dx,
+		struct wlr_box confine_box = seat->clone_confine_box;
+
+		if (seat->cursor->x + delta_x >= confine_box.width) {
+			delta_x = confine_box.width - seat->cursor->x;
+		}
+
+		if (seat->cursor->y + delta_y >= confine_box.height) {
+			delta_y = confine_box.height - seat->cursor->y;
+		}
+	}
+
+	wlr_cursor_move(seat->cursor, &event->pointer->base, delta_x, delta_y);
+	process_cursor_motion(seat, event->time_msec, delta_x, delta_y, event->unaccel_dx,
 			      event->unaccel_dy);
 	wlr_idle_notifier_v1_notify_activity(seat->server->idle, seat->seat);
 }
@@ -978,6 +993,34 @@ seat_center_cursor(struct cg_seat *seat)
 {
 	/* Place the cursor in the center of the output layout. */
 	struct wlr_box layout_box;
-	wlr_output_layout_get_box(seat->server->output_layout, NULL, &layout_box);
+	if (seat->server->clone_mode) {
+		layout_box = seat->clone_confine_box;
+	} else {
+		wlr_output_layout_get_box(seat->server->output_layout, NULL, &layout_box);
+	}
 	wlr_cursor_warp(seat->cursor, NULL, layout_box.width / 2, layout_box.height / 2);
 }
+
+void
+seat_get_clone_confines(struct cg_server *server, struct wlr_box *confine_box)
+{
+	int width = 0;
+	int height = 0;
+	struct cg_output *output;
+
+	/* Get the smallest dimensions out of all the screens */
+	wl_list_for_each (output, &server->outputs, link) {
+		if (width == 0 || width > output->wlr_output->width) {
+			width = output->wlr_output->width;
+		}
+
+		if (height == 0 || height > output->wlr_output->height) {
+			height = output->wlr_output->height;
+		}
+	}
+
+	confine_box->x = 0;
+	confine_box->y = 0;
+	confine_box->width = width;
+	confine_box->height = height;
+}

seat.h

@@ -48,6 +48,8 @@ struct cg_seat {
 	struct wl_listener request_set_cursor;
 	struct wl_listener request_set_selection;
 	struct wl_listener request_set_primary_selection;
+
+	struct wlr_box clone_confine_box;
 };
 
 struct cg_keyboard_group {
@@ -92,5 +94,6 @@ void seat_destroy(struct cg_seat *seat);
 struct cg_view *seat_get_focus(struct cg_seat *seat);
 void seat_set_focus(struct cg_seat *seat, struct cg_view *view);
 void seat_center_cursor(struct cg_seat *seat);
+void seat_get_clone_confines(struct cg_server *server, struct wlr_box *confine_box);
 
 #endif

server.h

@@ -70,6 +70,7 @@ struct cg_server {
 
 	struct wlr_foreign_toplevel_manager_v1 *foreign_toplevel_manager;
 
+	bool clone_mode;
 	bool xdg_decoration;
 	bool allow_vt_switch;
 	bool return_app_code;

view.c

@@ -60,7 +60,12 @@ view_extends_output_layout(struct cg_view *view, struct wlr_box *layout_box)
 	int width, height;
 	view->impl->get_geometry(view, &width, &height);
 
-	return (layout_box->height < height || layout_box->width < width);
+	if (view->server->clone_mode) {
+		struct wlr_box confine_box = view->server->seat->clone_confine_box;
+		return (confine_box.height < height || confine_box.width < width);
+	} else {
+		return (layout_box->height < height || layout_box->width < width);
+	}
 }
 
 static void
@@ -73,7 +78,12 @@ view_maximize(struct cg_view *view, struct wlr_box *layout_box)
 		wlr_scene_node_set_position(&view->scene_tree->node, view->lx, view->ly);
 	}
 
-	view->impl->maximize(view, layout_box->width, layout_box->height);
+	if (view->server->clone_mode) {
+		struct wlr_box confine_box = view->server->seat->clone_confine_box;
+		view->impl->maximize(view, confine_box.width, confine_box.height);
+	} else {
+		view->impl->maximize(view, layout_box->width, layout_box->height);
+	}
 }
 
 static void
@@ -82,8 +92,14 @@ view_center(struct cg_view *view, struct wlr_box *layout_box)
 	int width, height;
 	view->impl->get_geometry(view, &width, &height);
 
-	view->lx = (layout_box->width - width) / 2;
+	if (view->server->clone_mode) {
-	view->ly = (layout_box->height - height) / 2;
+		struct wlr_box confine_box = view->server->seat->clone_confine_box;
+		view->lx = (confine_box.width - width) / 2;
+		view->ly = (confine_box.height - height) / 2;
+	} else {
+		view->lx = (layout_box->width - width) / 2;
+		view->ly = (layout_box->height - height) / 2;
+	}
 
 	if (view->scene_tree) {
 		wlr_scene_node_set_position(&view->scene_tree->node, view->lx, view->ly);

xdg_shell.c

@@ -15,6 +15,7 @@
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
 
+#include "seat.h"
 #include "server.h"
 #include "view.h"
 #include "xdg_shell.h"
@@ -100,7 +101,11 @@ popup_unconstrain(struct wlr_xdg_popup *popup)
 	struct wlr_output *wlr_output =
 		wlr_output_layout_output_at(output_layout, view->lx + popup_box->x, view->ly + popup_box->y);
 	struct wlr_box output_box;
-	wlr_output_layout_get_box(output_layout, wlr_output, &output_box);
+	if (server->clone_mode) {
+		output_box = server->seat->clone_confine_box;
+	} else {
+		wlr_output_layout_get_box(output_layout, wlr_output, &output_box);
+	}
 
 	struct wlr_box output_toplevel_box = {
 		.x = output_box.x - view->lx,