Merge pull request #2703 from RyanDwyer/csd-border

Add CSD to border modes

include/sway/server.h

@@ -54,6 +54,10 @@ struct sway_server {
 	struct wl_listener server_decoration;
 	struct wl_list decorations; // sway_server_decoration::link
 
+	struct wlr_xdg_decoration_manager_v1 *xdg_decoration_manager;
+	struct wl_listener xdg_decoration;
+	struct wl_list xdg_decorations; // sway_xdg_decoration::link
+
 	size_t txn_timeout_ms;
 	list_t *transactions;
 	list_t *dirty_nodes;
@@ -78,5 +82,6 @@ void handle_xdg_shell_surface(struct wl_listener *listener, void *data);
 void handle_xwayland_surface(struct wl_listener *listener, void *data);
 #endif
 void handle_server_decoration(struct wl_listener *listener, void *data);
+void handle_xdg_decoration(struct wl_listener *listener, void *data);
 
 #endif

include/sway/tree/container.h

@@ -28,6 +28,7 @@ enum sway_container_border {
 	B_NONE,
 	B_PIXEL,
 	B_NORMAL,
+	B_CSD,
 };
 
 struct sway_root;
@@ -63,7 +64,6 @@ struct sway_container_state {
 	bool border_bottom;
 	bool border_left;
 	bool border_right;
-	bool using_csd;
 };
 
 struct sway_container {

include/sway/tree/view.h

@@ -11,6 +11,7 @@
 #include "sway/input/seat.h"
 
 struct sway_container;
+struct sway_xdg_decoration;
 
 enum sway_view_type {
 	SWAY_VIEW_XDG_SHELL_V6,
@@ -44,7 +45,6 @@ struct sway_view_impl {
 	void (*set_tiled)(struct sway_view *view, bool tiled);
 	void (*set_fullscreen)(struct sway_view *view, bool fullscreen);
 	bool (*wants_floating)(struct sway_view *view);
-	bool (*has_client_side_decorations)(struct sway_view *view);
 	void (*for_each_surface)(struct sway_view *view,
 		wlr_surface_iterator_func_t iterator, void *user_data);
 	void (*for_each_popup)(struct sway_view *view,
@@ -60,6 +60,7 @@ struct sway_view {
 
 	struct sway_container *container; // NULL if unmapped and transactions finished
 	struct wlr_surface *surface; // NULL for unmapped views
+	struct sway_xdg_decoration *xdg_decoration;
 
 	pid_t pid;
 
@@ -75,13 +76,24 @@ struct sway_view {
 	int natural_width, natural_height;
 
 	char *title_format;
+
+	// Our border types are B_NONE, B_PIXEL, B_NORMAL and B_CSD. We normally
+	// just assign this to the border property and ignore the other two.
+	// However, when a view using CSD is tiled, we want to render our own
+	// borders as well. So in this case the border property becomes one of the
+	// first three, and using_csd is true.
+	// Lastly, views can change their decoration mode at any time. When an SSD
+	// view becomes CSD without our approval, we save the SSD border type so it
+	// can be restored if/when the view returns from CSD to SSD.
 	enum sway_container_border border;
+	enum sway_container_border saved_border;
+	bool using_csd;
+
 	int border_thickness;
 	bool border_top;
 	bool border_bottom;
 	bool border_left;
 	bool border_right;
-	bool using_csd;
 
 	struct timespec urgent;
 	bool allow_request_urgent;
@@ -127,8 +139,6 @@ struct sway_view {
 struct sway_xdg_shell_v6_view {
 	struct sway_view view;
 
-	enum wlr_server_decoration_manager_mode deco_mode;
-
 	struct wl_listener commit;
 	struct wl_listener request_move;
 	struct wl_listener request_resize;
@@ -145,8 +155,6 @@ struct sway_xdg_shell_v6_view {
 struct sway_xdg_shell_view {
 	struct sway_view view;
 
-	enum wlr_server_decoration_manager_mode deco_mode;
-
 	struct wl_listener commit;
 	struct wl_listener request_move;
 	struct wl_listener request_resize;
@@ -175,6 +183,7 @@ struct sway_xwayland_view {
 	struct wl_listener set_role;
 	struct wl_listener set_window_type;
 	struct wl_listener set_hints;
+	struct wl_listener set_decorations;
 	struct wl_listener map;
 	struct wl_listener unmap;
 	struct wl_listener destroy;
@@ -275,6 +284,17 @@ void view_set_activated(struct sway_view *view, bool activated);
  */
 void view_request_activate(struct sway_view *view);
 
+/**
+ * If possible, instructs the client to change their decoration mode.
+ */
+void view_set_csd_from_server(struct sway_view *view, bool enabled);
+
+/**
+ * Updates the view's border setting when the client unexpectedly changes their
+ * decoration mode.
+ */
+void view_update_csd_from_client(struct sway_view *view, bool enabled);
+
 void view_set_tiled(struct sway_view *view, bool tiled);
 
 void view_close(struct sway_view *view);

include/sway/xdg_decoration.h

@@ -0,0 +1,19 @@
+#ifndef _SWAY_XDG_DECORATION_H
+#define _SWAY_XDG_DECORATION_H
+
+#include <wlr/types/wlr_xdg_decoration_v1.h>
+
+struct sway_xdg_decoration {
+	struct wlr_xdg_toplevel_decoration_v1 *wlr_xdg_decoration;
+	struct wl_list link;
+
+	struct sway_view *view;
+
+	struct wl_listener destroy;
+	struct wl_listener request_mode;
+};
+
+struct sway_xdg_decoration *xdg_decoration_from_surface(
+	struct wlr_surface *surface);
+
+#endif

sway/commands/border.c

@@ -7,6 +7,51 @@
 #include "sway/tree/container.h"
 #include "sway/tree/view.h"
 
+// A couple of things here:
+// - view->border should never be B_CSD when the view is tiled, even when CSD is
+//   in use (we set using_csd instead and render a sway border).
+// - view->saved_border should be the last applied border when switching to CSD.
+// - view->using_csd should always reflect whether CSD is applied or not.
+static void set_border(struct sway_view *view,
+		enum sway_container_border new_border) {
+	if (view->using_csd && new_border != B_CSD) {
+		view_set_csd_from_server(view, false);
+	} else if (!view->using_csd && new_border == B_CSD) {
+		view_set_csd_from_server(view, true);
+		view->saved_border = view->border;
+	}
+	if (new_border != B_CSD || container_is_floating(view->container)) {
+		view->border = new_border;
+	}
+	view->using_csd = new_border == B_CSD;
+}
+
+static void border_toggle(struct sway_view *view) {
+	if (view->using_csd) {
+		set_border(view, B_NONE);
+		return;
+	}
+	switch (view->border) {
+	case B_NONE:
+		set_border(view, B_PIXEL);
+		break;
+	case B_PIXEL:
+		set_border(view, B_NORMAL);
+		break;
+	case B_NORMAL:
+		if (view->xdg_decoration) {
+			set_border(view, B_CSD);
+		} else {
+			set_border(view, B_NONE);
+		}
+		break;
+	case B_CSD:
+		// view->using_csd should be true so it would have returned above
+		sway_assert(false, "Unreachable");
+		break;
+	}
+}
+
 struct cmd_results *cmd_border(int argc, char **argv) {
 	struct cmd_results *error = NULL;
 	if ((error = checkarg(argc, "border", EXPECTED_AT_LEAST, 1))) {
@@ -21,13 +66,19 @@ struct cmd_results *cmd_border(int argc, char **argv) {
 	struct sway_view *view = container->view;
 
 	if (strcmp(argv[0], "none") == 0) {
-		view->border = B_NONE;
+		set_border(view, B_NONE);
 	} else if (strcmp(argv[0], "normal") == 0) {
-		view->border = B_NORMAL;
+		set_border(view, B_NORMAL);
 	} else if (strcmp(argv[0], "pixel") == 0) {
-		view->border = B_PIXEL;
+		set_border(view, B_PIXEL);
+	} else if (strcmp(argv[0], "csd") == 0) {
+		if (!view->xdg_decoration) {
+			return cmd_results_new(CMD_INVALID, "border",
+					"This window doesn't support client side decorations");
+		}
+		set_border(view, B_CSD);
 	} else if (strcmp(argv[0], "toggle") == 0) {
-		view->border = (view->border + 1) % 3;
+		border_toggle(view);
 	} else {
 		return cmd_results_new(CMD_INVALID, "border",
 				"Expected 'border <none|normal|pixel|toggle>' "

sway/decoration.c

@@ -1,6 +1,8 @@
 #include <stdlib.h>
 #include "sway/decoration.h"
+#include "sway/desktop/transaction.h"
 #include "sway/server.h"
+#include "sway/tree/arrange.h"
 #include "sway/tree/view.h"
 #include "log.h"
 
@@ -24,20 +26,12 @@ static void server_decoration_handle_mode(struct wl_listener *listener,
 		return;
 	}
 
-	switch (view->type) {
-	case SWAY_VIEW_XDG_SHELL_V6:;
-		struct sway_xdg_shell_v6_view *xdg_shell_v6_view =
-			(struct sway_xdg_shell_v6_view *)view;
-		xdg_shell_v6_view->deco_mode = deco->wlr_server_decoration->mode;
-		break;
-	case SWAY_VIEW_XDG_SHELL:;
-		struct sway_xdg_shell_view *xdg_shell_view =
-			(struct sway_xdg_shell_view *)view;
-		xdg_shell_view->deco_mode = deco->wlr_server_decoration->mode;
-		break;
-	default:
-		break;
-	}
+	bool csd = deco->wlr_server_decoration->mode ==
+			WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
+	view_update_csd_from_client(view, csd);
+
+	arrange_container(view->container);
+	transaction_commit_dirty();
 }
 
 void handle_server_decoration(struct wl_listener *listener, void *data) {

sway/desktop/render.c

@@ -272,7 +272,7 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
 		render_view_toplevels(view, output, damage, view->container->alpha);
 	}
 
-	if (view->container->current.using_csd) {
+	if (con->current.border == B_NONE || con->current.border == B_CSD) {
 		return;
 	}
 
@@ -281,51 +281,49 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
 	float color[4];
 	struct sway_container_state *state = &con->current;
 
-	if (state->border != B_NONE) {
-		if (state->border_left) {
-			memcpy(&color, colors->child_border, sizeof(float) * 4);
-			premultiply_alpha(color, con->alpha);
-			box.x = state->con_x;
-			box.y = state->view_y;
-			box.width = state->border_thickness;
-			box.height = state->view_height;
-			scale_box(&box, output_scale);
-			render_rect(output->wlr_output, damage, &box, color);
-		}
+	if (state->border_left) {
+		memcpy(&color, colors->child_border, sizeof(float) * 4);
+		premultiply_alpha(color, con->alpha);
+		box.x = state->con_x;
+		box.y = state->view_y;
+		box.width = state->border_thickness;
+		box.height = state->view_height;
+		scale_box(&box, output_scale);
+		render_rect(output->wlr_output, damage, &box, color);
+	}
 
-		list_t *siblings = container_get_current_siblings(con);
-		enum sway_container_layout layout =
-			container_current_parent_layout(con);
+	list_t *siblings = container_get_current_siblings(con);
+	enum sway_container_layout layout =
+		container_current_parent_layout(con);
 
-		if (state->border_right) {
-			if (siblings->length == 1 && layout == L_HORIZ) {
-				memcpy(&color, colors->indicator, sizeof(float) * 4);
-			} else {
-				memcpy(&color, colors->child_border, sizeof(float) * 4);
-			}
-			premultiply_alpha(color, con->alpha);
-			box.x = state->view_x + state->view_width;
-			box.y = state->view_y;
-			box.width = state->border_thickness;
-			box.height = state->view_height;
-			scale_box(&box, output_scale);
-			render_rect(output->wlr_output, damage, &box, color);
+	if (state->border_right) {
+		if (siblings->length == 1 && layout == L_HORIZ) {
+			memcpy(&color, colors->indicator, sizeof(float) * 4);
+		} else {
+			memcpy(&color, colors->child_border, sizeof(float) * 4);
 		}
+		premultiply_alpha(color, con->alpha);
+		box.x = state->view_x + state->view_width;
+		box.y = state->view_y;
+		box.width = state->border_thickness;
+		box.height = state->view_height;
+		scale_box(&box, output_scale);
+		render_rect(output->wlr_output, damage, &box, color);
+	}
 
-		if (state->border_bottom) {
-			if (siblings->length == 1 && layout == L_VERT) {
-				memcpy(&color, colors->indicator, sizeof(float) * 4);
-			} else {
-				memcpy(&color, colors->child_border, sizeof(float) * 4);
-			}
-			premultiply_alpha(color, con->alpha);
-			box.x = state->con_x;
-			box.y = state->view_y + state->view_height;
-			box.width = state->con_width;
-			box.height = state->border_thickness;
-			scale_box(&box, output_scale);
-			render_rect(output->wlr_output, damage, &box, color);
+	if (state->border_bottom) {
+		if (siblings->length == 1 && layout == L_VERT) {
+			memcpy(&color, colors->indicator, sizeof(float) * 4);
+		} else {
+			memcpy(&color, colors->child_border, sizeof(float) * 4);
 		}
+		premultiply_alpha(color, con->alpha);
+		box.x = state->con_x;
+		box.y = state->view_y + state->view_height;
+		box.width = state->con_width;
+		box.height = state->border_thickness;
+		scale_box(&box, output_scale);
+		render_rect(output->wlr_output, damage, &box, color);
 	}
 }
 
@@ -645,14 +643,12 @@ static void render_containers_linear(struct sway_output *output,
 				marks_texture = view->marks_unfocused;
 			}
 
-			if (!view->container->current.using_csd) {
-				if (state->border == B_NORMAL) {
-					render_titlebar(output, damage, child, state->con_x,
-							state->con_y, state->con_width, colors,
-							title_texture, marks_texture);
-				} else {
-					render_top_border(output, damage, child, colors);
-				}
+			if (state->border == B_NORMAL) {
+				render_titlebar(output, damage, child, state->con_x,
+						state->con_y, state->con_width, colors,
+						title_texture, marks_texture);
+			} else if (state->border == B_PIXEL) {
+				render_top_border(output, damage, child, colors);
 			}
 			render_view(output, damage, child, colors);
 		} else {
@@ -859,14 +855,12 @@ static void render_floating_container(struct sway_output *soutput,
 			marks_texture = view->marks_unfocused;
 		}
 
-		if (!view->container->current.using_csd) {
-			if (con->current.border == B_NORMAL) {
-				render_titlebar(soutput, damage, con, con->current.con_x,
-						con->current.con_y, con->current.con_width, colors,
-						title_texture, marks_texture);
-			} else if (con->current.border != B_NONE) {
-				render_top_border(soutput, damage, con, colors);
-			}
+		if (con->current.border == B_NORMAL) {
+			render_titlebar(soutput, damage, con, con->current.con_x,
+					con->current.con_y, con->current.con_width, colors,
+					title_texture, marks_texture);
+		} else if (con->current.border == B_PIXEL) {
+			render_top_border(soutput, damage, con, colors);
 		}
 		render_view(soutput, damage, con, colors);
 	} else {

sway/desktop/transaction.c

@@ -148,7 +148,6 @@ static void copy_container_state(struct sway_container *container,
 		state->border_left = view->border_left;
 		state->border_right = view->border_right;
 		state->border_bottom = view->border_bottom;
-		state->using_csd = view->using_csd;
 	} else {
 		state->children = create_list();
 		list_cat(state->children, container->children);

sway/desktop/xdg_shell.c

@@ -175,15 +175,6 @@ static bool wants_floating(struct sway_view *view) {
 		|| toplevel->parent;
 }
 
-static bool has_client_side_decorations(struct sway_view *view) {
-	struct sway_xdg_shell_view *xdg_shell_view =
-		xdg_shell_view_from_view(view);
-	if (xdg_shell_view == NULL) {
-		return true;
-	}
-	return xdg_shell_view->deco_mode != WLR_SERVER_DECORATION_MANAGER_MODE_SERVER;
-}
-
 static void for_each_surface(struct sway_view *view,
 		wlr_surface_iterator_func_t iterator, void *user_data) {
 	if (xdg_shell_view_from_view(view) == NULL) {
@@ -240,7 +231,6 @@ static const struct sway_view_impl view_impl = {
 	.set_tiled = set_tiled,
 	.set_fullscreen = set_fullscreen,
 	.wants_floating = wants_floating,
-	.has_client_side_decorations = has_client_side_decorations,
 	.for_each_surface = for_each_surface,
 	.for_each_popup = for_each_popup,
 	.close = _close,
@@ -385,16 +375,16 @@ static void handle_map(struct wl_listener *listener, void *data) {
 		view->natural_height = view->wlr_xdg_surface->surface->current.height;
 	}
 
-	struct sway_server_decoration *deco =
-		decoration_from_surface(xdg_surface->surface);
-	if (deco != NULL) {
-		xdg_shell_view->deco_mode = deco->wlr_server_decoration->mode;
-	} else {
-		xdg_shell_view->deco_mode = WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
-	}
-
 	view_map(view, view->wlr_xdg_surface->surface);
 
+	if (!view->xdg_decoration) {
+		struct sway_server_decoration *deco =
+			decoration_from_surface(xdg_surface->surface);
+		bool csd = !deco || deco->wlr_server_decoration->mode ==
+			WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
+		view_update_csd_from_client(view, csd);
+	}
+
 	if (xdg_surface->toplevel->client_pending.fullscreen) {
 		container_set_fullscreen(view->container, true);
 		arrange_workspace(view->container->workspace);

sway/desktop/xdg_shell_v6.c

@@ -171,15 +171,6 @@ static bool wants_floating(struct sway_view *view) {
 		|| toplevel->parent;
 }
 
-static bool has_client_side_decorations(struct sway_view *view) {
-	struct sway_xdg_shell_v6_view *xdg_shell_v6_view =
-		xdg_shell_v6_view_from_view(view);
-	if (xdg_shell_v6_view == NULL) {
-		return true;
-	}
-	return xdg_shell_v6_view->deco_mode != WLR_SERVER_DECORATION_MANAGER_MODE_SERVER;
-}
-
 static void for_each_surface(struct sway_view *view,
 		wlr_surface_iterator_func_t iterator, void *user_data) {
 	if (xdg_shell_v6_view_from_view(view) == NULL) {
@@ -237,7 +228,6 @@ static const struct sway_view_impl view_impl = {
 	.set_tiled = set_tiled,
 	.set_fullscreen = set_fullscreen,
 	.wants_floating = wants_floating,
-	.has_client_side_decorations = has_client_side_decorations,
 	.for_each_surface = for_each_surface,
 	.for_each_popup = for_each_popup,
 	.close = _close,
@@ -382,15 +372,13 @@ static void handle_map(struct wl_listener *listener, void *data) {
 		view->natural_height = view->wlr_xdg_surface_v6->surface->current.height;
 	}
 
+	view_map(view, view->wlr_xdg_surface_v6->surface);
+
 	struct sway_server_decoration *deco =
 		decoration_from_surface(xdg_surface->surface);
-	if (deco != NULL) {
-		xdg_shell_v6_view->deco_mode = deco->wlr_server_decoration->mode;
-	} else {
-		xdg_shell_v6_view->deco_mode = WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
-	}
-
-	view_map(view, view->wlr_xdg_surface_v6->surface);
+	bool csd = !deco || deco->wlr_server_decoration->mode ==
+			WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
+	view_update_csd_from_client(view, csd);
 
 	if (xdg_surface->toplevel->client_pending.fullscreen) {
 		container_set_fullscreen(view->container, true);

sway/desktop/xwayland.c

@@ -243,12 +243,14 @@ static bool wants_floating(struct sway_view *view) {
 	return false;
 }
 
-static bool has_client_side_decorations(struct sway_view *view) {
-	if (xwayland_view_from_view(view) == NULL) {
-		return false;
-	}
-	struct wlr_xwayland_surface *surface = view->wlr_xwayland_surface;
-	return surface->decorations != WLR_XWAYLAND_SURFACE_DECORATIONS_ALL;
+static void handle_set_decorations(struct wl_listener *listener, void *data) {
+	struct sway_xwayland_view *xwayland_view =
+		wl_container_of(listener, xwayland_view, set_decorations);
+	struct sway_view *view = &xwayland_view->view;
+	struct wlr_xwayland_surface *xsurface = view->wlr_xwayland_surface;
+
+	bool csd = xsurface->decorations != WLR_XWAYLAND_SURFACE_DECORATIONS_ALL;
+	view_update_csd_from_client(view, csd);
 }
 
 static void _close(struct sway_view *view) {
@@ -274,7 +276,6 @@ static const struct sway_view_impl view_impl = {
 	.set_tiled = set_tiled,
 	.set_fullscreen = set_fullscreen,
 	.wants_floating = wants_floating,
-	.has_client_side_decorations = has_client_side_decorations,
 	.close = _close,
 	.destroy = destroy,
 };
@@ -343,6 +344,7 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_list_remove(&xwayland_view->set_role.link);
 	wl_list_remove(&xwayland_view->set_window_type.link);
 	wl_list_remove(&xwayland_view->set_hints.link);
+	wl_list_remove(&xwayland_view->set_decorations.link);
 	wl_list_remove(&xwayland_view->map.link);
 	wl_list_remove(&xwayland_view->unmap.link);
 	view_begin_destroy(&xwayland_view->view);
@@ -613,6 +615,10 @@ void handle_xwayland_surface(struct wl_listener *listener, void *data) {
 	wl_signal_add(&xsurface->events.set_hints, &xwayland_view->set_hints);
 	xwayland_view->set_hints.notify = handle_set_hints;
 
+	wl_signal_add(&xsurface->events.set_decorations,
+			&xwayland_view->set_decorations);
+	xwayland_view->set_decorations.notify = handle_set_decorations;
+
 	wl_signal_add(&xsurface->events.unmap, &xwayland_view->unmap);
 	xwayland_view->unmap.notify = handle_unmap;
 

sway/input/cursor.c

@@ -175,7 +175,8 @@ static enum wlr_edges find_edge(struct sway_container *cont,
 		return WLR_EDGE_NONE;
 	}
 	struct sway_view *view = cont->view;
-	if (view->border == B_NONE || !view->border_thickness || view->using_csd) {
+	if (view->border == B_NONE || !view->border_thickness ||
+			view->border == B_CSD) {
 		return WLR_EDGE_NONE;
 	}
 

sway/ipc-json.c

@@ -216,6 +216,8 @@ static const char *describe_container_border(enum sway_container_border border)
 		return "pixel";
 	case B_NORMAL:
 		return "normal";
+	case B_CSD:
+		return "csd";
 	}
 	return "unknown";
 }

sway/meson.build

@@ -10,6 +10,7 @@ sway_sources = files(
 	'security.c',
 	'server.c',
 	'swaynag.c',
+	'xdg_decoration.c',
 
 	'desktop/desktop.c',
 	'desktop/idle_inhibit_v1.c',

sway/server.c

@@ -16,6 +16,7 @@
 #include <wlr/types/wlr_screencopy_v1.h>
 #include <wlr/types/wlr_server_decoration.h>
 #include <wlr/types/wlr_xcursor_manager.h>
+#include <wlr/types/wlr_xdg_decoration_v1.h>
 #include <wlr/types/wlr_xdg_output_v1.h>
 #include <wlr/util/log.h>
 #include "list.h"
@@ -115,6 +116,14 @@ bool server_init(struct sway_server *server) {
 	server->server_decoration.notify = handle_server_decoration;
 	wl_list_init(&server->decorations);
 
+	server->xdg_decoration_manager =
+		wlr_xdg_decoration_manager_v1_create(server->wl_display);
+	wl_signal_add(
+			&server->xdg_decoration_manager->events.new_toplevel_decoration,
+			&server->xdg_decoration);
+	server->xdg_decoration.notify = handle_xdg_decoration;
+	wl_list_init(&server->xdg_decorations);
+
 	wlr_export_dmabuf_manager_v1_create(server->wl_display);
 	wlr_screencopy_manager_v1_create(server->wl_display);
 

sway/tree/container.c

@@ -669,6 +669,9 @@ void container_set_floating(struct sway_container *container, bool enable) {
 		container_init_floating(container);
 		if (container->view) {
 			view_set_tiled(container->view, false);
+			if (container->view->using_csd) {
+				container->view->border = B_CSD;
+			}
 		}
 		if (old_parent) {
 			container_reap_empty(old_parent);
@@ -695,6 +698,9 @@ void container_set_floating(struct sway_container *container, bool enable) {
 		}
 		if (container->view) {
 			view_set_tiled(container->view, true);
+			if (container->view->using_csd) {
+				container->view->border = container->view->saved_border;
+			}
 		}
 		container->is_sticky = false;
 	}
@@ -715,7 +721,7 @@ void container_set_geometry_from_floating_view(struct sway_container *con) {
 	size_t border_width = 0;
 	size_t top = 0;
 
-	if (!view->using_csd) {
+	if (view->border != B_CSD) {
 		border_width = view->border_thickness * (view->border != B_NONE);
 		top = view->border == B_NORMAL ?
 			container_titlebar_height() : border_width;

sway/tree/view.c

@@ -5,6 +5,8 @@
 #include <wlr/render/wlr_renderer.h>
 #include <wlr/types/wlr_buffer.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_server_decoration.h>
+#include <wlr/types/wlr_xdg_decoration_v1.h>
 #include "config.h"
 #ifdef HAVE_XWAYLAND
 #include <wlr/xwayland.h>
@@ -23,6 +25,7 @@
 #include "sway/tree/view.h"
 #include "sway/tree/workspace.h"
 #include "sway/config.h"
+#include "sway/xdg_decoration.h"
 #include "pango.h"
 #include "stringop.h"
 
@@ -248,12 +251,8 @@ void view_autoconfigure(struct sway_view *view) {
 		view->border_top = false;
 	}
 
-	enum sway_container_border border = view->border;
-	if (view->using_csd) {
-		border = B_NONE;
-	}
-
-	switch (border) {
+	switch (view->border) {
+	case B_CSD:
 	case B_NONE:
 		x = con->x;
 		y = con->y + y_offset;
@@ -326,16 +325,32 @@ void view_request_activate(struct sway_view *view) {
 	}
 }
 
-void view_set_tiled(struct sway_view *view, bool tiled) {
-	if (!tiled) {
-		view->using_csd = true;
-		if (view->impl->has_client_side_decorations) {
-			view->using_csd = view->impl->has_client_side_decorations(view);
+void view_set_csd_from_server(struct sway_view *view, bool enabled) {
+	wlr_log(WLR_DEBUG, "Telling view %p to set CSD to %i", view, enabled);
+	if (view->xdg_decoration) {
+		uint32_t mode = enabled ?
+			WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_CLIENT_SIDE :
+			WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE;
+		wlr_xdg_toplevel_decoration_v1_set_mode(
+				view->xdg_decoration->wlr_xdg_decoration, mode);
+	}
+	view->using_csd = enabled;
+}
+
+void view_update_csd_from_client(struct sway_view *view, bool enabled) {
+	wlr_log(WLR_DEBUG, "View %p updated CSD to %i", view, enabled);
+	if (enabled && view->border != B_CSD) {
+		view->saved_border = view->border;
+		if (container_is_floating(view->container)) {
+			view->border = B_CSD;
 		}
-	} else {
-		view->using_csd = false;
+	} else if (!enabled && view->border == B_CSD) {
+		view->border = view->saved_border;
 	}
+	view->using_csd = enabled;
+}
 
+void view_set_tiled(struct sway_view *view, bool tiled) {
 	if (view->impl->set_tiled) {
 		view->impl->set_tiled(view, tiled);
 	}

sway/xdg_decoration.c

@@ -0,0 +1,59 @@
+#include <stdlib.h>
+#include "sway/desktop/transaction.h"
+#include "sway/server.h"
+#include "sway/tree/arrange.h"
+#include "sway/tree/view.h"
+#include "sway/xdg_decoration.h"
+#include "log.h"
+
+static void xdg_decoration_handle_destroy(struct wl_listener *listener,
+		void *data) {
+	struct sway_xdg_decoration *deco =
+		wl_container_of(listener, deco, destroy);
+	deco->view->xdg_decoration = NULL;
+	wl_list_remove(&deco->destroy.link);
+	wl_list_remove(&deco->request_mode.link);
+	wl_list_remove(&deco->link);
+	free(deco);
+}
+
+static void xdg_decoration_handle_request_mode(struct wl_listener *listener,
+		void *data) {
+	struct sway_xdg_decoration *deco =
+		wl_container_of(listener, deco, request_mode);
+	wlr_xdg_toplevel_decoration_v1_set_mode(deco->wlr_xdg_decoration,
+			WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE);
+}
+
+void handle_xdg_decoration(struct wl_listener *listener, void *data) {
+	struct wlr_xdg_toplevel_decoration_v1 *wlr_deco = data;
+	struct sway_xdg_shell_view *xdg_shell_view = wlr_deco->surface->data;
+
+	struct sway_xdg_decoration *deco = calloc(1, sizeof(*deco));
+	if (deco == NULL) {
+		return;
+	}
+
+	deco->view = &xdg_shell_view->view;
+	deco->view->xdg_decoration = deco;
+	deco->wlr_xdg_decoration = wlr_deco;
+
+	wl_signal_add(&wlr_deco->events.destroy, &deco->destroy);
+	deco->destroy.notify = xdg_decoration_handle_destroy;
+
+	wl_signal_add(&wlr_deco->events.request_mode, &deco->request_mode);
+	deco->request_mode.notify = xdg_decoration_handle_request_mode;
+
+	wl_list_insert(&server.xdg_decorations, &deco->link);
+}
+
+struct sway_xdg_decoration *xdg_decoration_from_surface(
+		struct wlr_surface *surface) {
+	struct sway_xdg_decoration *deco;
+	wl_list_for_each(deco, &server.xdg_decorations, link) {
+		if (deco->wlr_xdg_decoration->surface->surface == surface) {
+			return deco;
+		}
+	}
+	return NULL;
+}