19 files changed, 256 insertions, 46 deletions

diff --git a/include/backend/drm/drm.h b/include/backend/drm/drm.h
index 72671f45..af472ede 100644
--- a/include/backend/drm/drm.h
+++ b/include/backend/drm/drm.h
@@ -123,8 +123,8 @@ struct wlr_drm_connector {
 
 	union wlr_drm_connector_props props;
 
-	uint32_t width;
-	uint32_t height;
+	uint32_t width, height;
+	int32_t cursor_x, cursor_y;
 
 	drmModeCrtc *old_crtc;
 
diff --git a/include/backend/drm/renderer.h b/include/backend/drm/renderer.h
index 45127cd0..a3f19fc3 100644
--- a/include/backend/drm/renderer.h
+++ b/include/backend/drm/renderer.h
@@ -45,7 +45,7 @@ bool wlr_drm_plane_surfaces_init(struct wlr_drm_plane *plane, struct wlr_drm_bac
 		int32_t width, uint32_t height, uint32_t format);
 
 void wlr_drm_surface_finish(struct wlr_drm_surface *surf);
-void wlr_drm_surface_make_current(struct wlr_drm_surface *surf);
+bool wlr_drm_surface_make_current(struct wlr_drm_surface *surf, int *buffer_age);
 struct gbm_bo *wlr_drm_surface_swap_buffers(struct wlr_drm_surface *surf);
 struct gbm_bo *wlr_drm_surface_get_front(struct wlr_drm_surface *surf);
 void wlr_drm_surface_post(struct wlr_drm_surface *surf);
diff --git a/include/rootston/desktop.h b/include/rootston/desktop.h
index 9dfd7b10..1232121a 100644
--- a/include/rootston/desktop.h
+++ b/include/rootston/desktop.h
@@ -16,15 +16,7 @@
 #include <wlr/types/wlr_idle.h>
 #include "rootston/view.h"
 #include "rootston/config.h"
-
-struct roots_output {
-	struct roots_desktop *desktop;
-	struct wlr_output *wlr_output;
-	struct wl_listener frame;
-	struct timespec last_frame;
-	struct wl_list link; // roots_desktop:outputs
-	struct roots_view *fullscreen_view;
-};
+#include "rootston/output.h"
 
 struct roots_desktop {
 	struct wl_list views; // roots_view::link
@@ -64,7 +56,7 @@ struct roots_desktop {
 struct roots_server;
 
 struct roots_desktop *desktop_create(struct roots_server *server,
-		struct roots_config *config);
+	struct roots_config *config);
 void desktop_destroy(struct roots_desktop *desktop);
 struct roots_output *desktop_output_from_wlr_output(
 	struct roots_desktop *desktop, struct wlr_output *output);
@@ -72,11 +64,12 @@ struct roots_view *desktop_view_at(struct roots_desktop *desktop, double lx,
 	double ly, struct wlr_surface **surface, double *sx, double *sy);
 
 void view_init(struct roots_view *view, struct roots_desktop *desktop);
-void view_destroy(struct roots_view *view);
+void view_finish(struct roots_view *view);
 void view_activate(struct roots_view *view, bool activate);
-
-void output_add_notify(struct wl_listener *listener, void *data);
-void output_remove_notify(struct wl_listener *listener, void *data);
+void view_apply_damage(struct roots_view *view);
+void view_damage_whole(struct roots_view *view);
+void view_update_position(struct roots_view *view, double x, double y);
+void view_update_size(struct roots_view *view, uint32_t width, uint32_t height);
 
 void handle_xdg_shell_v6_surface(struct wl_listener *listener, void *data);
 void handle_wl_shell_surface(struct wl_listener *listener, void *data);
diff --git a/include/rootston/output.h b/include/rootston/output.h
new file mode 100644
index 00000000..3a6d3cc7
--- /dev/null
+++ b/include/rootston/output.h
@@ -0,0 +1,50 @@
+#ifndef _ROOTSTON_OUTPUT_H
+#define _ROOTSTON_OUTPUT_H
+
+#include <time.h>
+#include <pixman.h>
+#include <wayland-server.h>
+
+/**
+ * Damage tracking requires to keep track of previous frames' damage. To allow
+ * damage tracking to work with triple buffering, a history of two frames is
+ * required.
+ */
+#define ROOTS_OUTPUT_PREVIOUS_DAMAGE_LEN 2
+
+struct roots_desktop;
+
+struct roots_output {
+	struct roots_desktop *desktop;
+	struct wlr_output *wlr_output;
+	struct wl_list link; // roots_desktop:outputs
+
+	struct roots_view *fullscreen_view;
+
+	struct timespec last_frame;
+	pixman_region32_t damage; // in ouput-local coordinates
+
+	// circular queue for previous damage
+	pixman_region32_t previous_damage[ROOTS_OUTPUT_PREVIOUS_DAMAGE_LEN];
+	size_t previous_damage_idx;
+
+	struct wl_listener frame;
+	struct wl_listener mode;
+	struct wl_listener needs_swap;
+};
+
+void output_add_notify(struct wl_listener *listener, void *data);
+void output_remove_notify(struct wl_listener *listener, void *data);
+
+struct roots_view;
+struct roots_drag_icon;
+
+void output_damage_whole(struct roots_output *output);
+void output_damage_whole_view(struct roots_output *output,
+	struct roots_view *view);
+void output_damage_from_view(struct roots_output *output,
+	struct roots_view *view);
+void output_damage_whole_drag_icon(struct roots_output *output,
+	struct roots_drag_icon *icon);
+
+#endif
diff --git a/include/rootston/seat.h b/include/rootston/seat.h
index 2be8e467..0047522c 100644
--- a/include/rootston/seat.h
+++ b/include/rootston/seat.h
@@ -17,12 +17,15 @@ struct roots_seat {
 	struct wl_list views; // roots_seat_view::link
 	bool has_focus;
 
+	struct wl_list drag_icons; // roots_drag_icon::link
+
 	struct wl_list keyboards;
 	struct wl_list pointers;
 	struct wl_list touch;
 	struct wl_list tablet_tools;
 
-	struct wl_listener seat_destroy;
+	struct wl_listener new_drag_icon;
+	struct wl_listener destroy;
 };
 
 struct roots_seat_view {
@@ -38,6 +41,18 @@ struct roots_seat_view {
 	struct wl_listener view_destroy;
 };
 
+struct roots_drag_icon {
+	struct roots_seat *seat;
+	struct wlr_drag_icon *wlr_drag_icon;
+	struct wl_list link;
+
+	double x, y;
+
+	struct wl_listener surface_commit;
+	struct wl_listener map;
+	struct wl_listener destroy;
+};
+
 struct roots_pointer {
 	struct roots_seat *seat;
 	struct wlr_input_device *device;
@@ -92,6 +107,10 @@ void roots_seat_begin_rotate(struct roots_seat *seat, struct roots_view *view);
 void roots_seat_end_compositor_grab(struct roots_seat *seat);
 
 struct roots_seat_view *roots_seat_view_from_view( struct roots_seat *seat,
-		struct roots_view *view);
+	struct roots_view *view);
+
+void roots_drag_icon_update_position(struct roots_drag_icon *icon);
+
+void roots_drag_icon_damage_whole(struct roots_drag_icon *icon);
 
 #endif
diff --git a/include/rootston/view.h b/include/rootston/view.h
index e1172bca..f6968c7a 100644
--- a/include/rootston/view.h
+++ b/include/rootston/view.h
@@ -11,6 +11,7 @@ struct roots_wl_shell_surface {
 	struct roots_view *view;
 
 	struct wl_listener destroy;
+	struct wl_listener new_popup;
 	struct wl_listener request_move;
 	struct wl_listener request_resize;
 	struct wl_listener request_maximize;
@@ -23,13 +24,15 @@ struct roots_wl_shell_surface {
 struct roots_xdg_surface_v6 {
 	struct roots_view *view;
 
-	struct wl_listener commit;
 	struct wl_listener destroy;
+	struct wl_listener new_popup;
 	struct wl_listener request_move;
 	struct wl_listener request_resize;
 	struct wl_listener request_maximize;
 	struct wl_listener request_fullscreen;
 
+	struct wl_listener surface_commit;
+
 	uint32_t pending_move_resize_configure_serial;
 };
 
@@ -61,6 +64,7 @@ struct roots_view {
 	struct wl_list link; // roots_desktop::views
 
 	double x, y;
+	uint32_t width, height;
 	float rotation;
 
 	bool decorated;
@@ -97,17 +101,17 @@ struct roots_view {
 		struct roots_xwayland_surface *roots_xwayland_surface;
 #endif
 	};
+
 	struct wlr_surface *wlr_surface;
+	struct wl_list children; // roots_view_child::link
+
+	struct wl_listener new_subsurface;
 
 	struct {
 		struct wl_signal destroy;
 	} events;
 
-	// TODO: This would probably be better as a field that's updated on a
-	// configure event from the xdg_shell
-	// If not then this should follow the typical type/impl pattern we use
-	// elsewhere
-	void (*get_size)(const struct roots_view *view, struct wlr_box *box);
+	// TODO: this should follow the typical type/impl pattern we use elsewhere
 	void (*activate)(struct roots_view *view, bool active);
 	void (*move)(struct roots_view *view, double x, double y);
 	void (*resize)(struct roots_view *view, uint32_t width, uint32_t height);
@@ -118,6 +122,38 @@ struct roots_view {
 	void (*close)(struct roots_view *view);
 };
 
+struct roots_view_child {
+	struct roots_view *view;
+	struct wlr_surface *wlr_surface;
+	struct wl_list link;
+
+	struct wl_listener commit;
+	struct wl_listener new_subsurface;
+
+	void (*destroy)(struct roots_view_child *child);
+};
+
+struct roots_subsurface {
+	struct roots_view_child view_child;
+	struct wlr_subsurface *wlr_subsurface;
+	struct wl_listener destroy;
+};
+
+struct roots_wl_shell_popup {
+	struct roots_view_child view_child;
+	struct wlr_wl_shell_surface *wlr_wl_shell_surface;
+	struct wl_listener destroy;
+	struct wl_listener set_state;
+	struct wl_listener new_popup;
+};
+
+struct roots_xdg_popup_v6 {
+	struct roots_view_child view_child;
+	struct wlr_xdg_popup_v6 *wlr_popup;
+	struct wl_listener destroy;
+	struct wl_listener new_popup;
+};
+
 void view_get_box(const struct roots_view *view, struct wlr_box *box);
 void view_activate(struct roots_view *view, bool active);
 void view_move(struct roots_view *view, double x, double y);
@@ -127,6 +163,7 @@ void view_move_resize(struct roots_view *view, double x, double y,
 void view_maximize(struct roots_view *view, bool maximized);
 void view_set_fullscreen(struct roots_view *view, bool fullscreen,
 	struct wlr_output *output);
+void view_rotate(struct roots_view *view, float rotation);
 void view_close(struct roots_view *view);
 bool view_center(struct roots_view *view);
 void view_setup(struct roots_view *view);
@@ -145,4 +182,11 @@ enum roots_deco_part {
 
 enum roots_deco_part view_get_deco_part(struct roots_view *view, double sx, double sy);
 
+void view_child_init(struct roots_view_child *child, struct roots_view *view,
+	struct wlr_surface *wlr_surface);
+void view_child_finish(struct roots_view_child *child);
+
+struct roots_subsurface *subsurface_create(struct roots_view *view,
+	struct wlr_subsurface *wlr_subsurface);
+
 #endif
diff --git a/include/wlr/interfaces/wlr_output.h b/include/wlr/interfaces/wlr_output.h
index d5837def..652be45e 100644
--- a/include/wlr/interfaces/wlr_output.h
+++ b/include/wlr/interfaces/wlr_output.h
@@ -18,8 +18,8 @@ struct wlr_output_impl {
 		int32_t hotspot_x, int32_t hotspot_y, bool update_pixels);
 	bool (*move_cursor)(struct wlr_output *output, int x, int y);
 	void (*destroy)(struct wlr_output *output);
-	void (*make_current)(struct wlr_output *output);
-	void (*swap_buffers)(struct wlr_output *output);
+	bool (*make_current)(struct wlr_output *output, int *buffer_age);
+	bool (*swap_buffers)(struct wlr_output *output);
 	void (*set_gamma)(struct wlr_output *output,
 		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 	uint32_t (*get_gamma_size)(struct wlr_output *output);
@@ -32,5 +32,7 @@ void wlr_output_update_mode(struct wlr_output *output,
 void wlr_output_update_custom_mode(struct wlr_output *output, int32_t width,
 	int32_t height, int32_t refresh);
 void wlr_output_update_enabled(struct wlr_output *output, bool enabled);
+void wlr_output_update_needs_swap(struct wlr_output *output);
+void wlr_output_send_frame(struct wlr_output *output);
 
 #endif
diff --git a/include/wlr/render.h b/include/wlr/render.h
index 00088b52..ccc66d36 100644
--- a/include/wlr/render.h
+++ b/include/wlr/render.h
@@ -5,6 +5,7 @@
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 #include <wayland-server-protocol.h>
+#include <wlr/types/wlr_box.h>
 #include <wlr/types/wlr_output.h>
 
 struct wlr_texture;
@@ -12,6 +13,13 @@ struct wlr_renderer;
 
 void wlr_renderer_begin(struct wlr_renderer *r, struct wlr_output *output);
 void wlr_renderer_end(struct wlr_renderer *r);
+void wlr_renderer_clear(struct wlr_renderer *r, const float (*color)[4]);
+/**
+ * Defines a scissor box. Only pixels that lie within the scissor box can be
+ * modified by drawing functions. Providing a NULL `box` disables the scissor
+ * box.
+ */
+void wlr_renderer_scissor(struct wlr_renderer *r, struct wlr_box *box);
 /**
  * Requests a texture handle from this renderer.
  */
diff --git a/include/wlr/render/egl.h b/include/wlr/render/egl.h
index bdb8d286..6979fd9b 100644
--- a/include/wlr/render/egl.h
+++ b/include/wlr/render/egl.h
@@ -11,8 +11,12 @@ struct wlr_egl {
 	EGLConfig config;
 	EGLContext context;
 
-	const char *egl_exts;
-	const char *gl_exts;
+	const char *egl_exts_str;
+	const char *gl_exts_str;
+
+	struct {
+		bool buffer_age;
+	} egl_exts;
 
 	struct wl_display *wl_display;
 };
@@ -65,4 +69,7 @@ bool wlr_egl_destroy_image(struct wlr_egl *egl, EGLImageKHR image);
  */
 const char *egl_error(void);
 
+bool wlr_egl_make_current(struct wlr_egl *egl, EGLSurface surface,
+	int *buffer_age);
+
 #endif
diff --git a/include/wlr/render/interface.h b/include/wlr/render/interface.h
index bb337409..b8e99898 100644
--- a/include/wlr/render/interface.h
+++ b/include/wlr/render/interface.h
@@ -6,6 +6,7 @@
 #include <EGL/eglext.h>
 #include <stdbool.h>
 #include <wlr/render.h>
+#include <wlr/types/wlr_box.h>
 #include <wlr/types/wlr_output.h>
 
 struct wlr_renderer_impl;
@@ -17,6 +18,8 @@ struct wlr_renderer {
 struct wlr_renderer_impl {
 	void (*begin)(struct wlr_renderer *renderer, struct wlr_output *output);
 	void (*end)(struct wlr_renderer *renderer);
+	void (*clear)(struct wlr_renderer *renderer, const float (*color)[4]);
+	void (*scissor)(struct wlr_renderer *renderer, struct wlr_box *box);
 	struct wlr_texture *(*texture_create)(struct wlr_renderer *renderer);
 	bool (*render_with_matrix)(struct wlr_renderer *renderer,
 		struct wlr_texture *texture, const float (*matrix)[16]);
diff --git a/include/wlr/types/wlr_box.h b/include/wlr/types/wlr_box.h
index 0588201c..fc86f0ac 100644
--- a/include/wlr/types/wlr_box.h
+++ b/include/wlr/types/wlr_box.h
@@ -2,6 +2,7 @@
 #define WLR_TYPES_WLR_BOX_H
 
 #include <stdbool.h>
+#include <wayland-server.h>
 
 struct wlr_box {
 	int x, y;
@@ -18,8 +19,17 @@ bool wlr_box_contains_point(const struct wlr_box *box, double x, double y);
 
 bool wlr_box_empty(const struct wlr_box *box);
 
-enum wl_output_transform;
+/**
+ * Transforms a box inside a `width` x `height` box.
+ */
 void wlr_box_transform(const struct wlr_box *box,
-	enum wl_output_transform transform, struct wlr_box *dest);
+	enum wl_output_transform transform, int width, int height,
+	struct wlr_box *dest);
+
+/**
+ * Creates the smallest box that contains a rotated box.
+ */
+void wlr_box_rotated_bounds(const struct wlr_box *box, float rotation,
+	struct wlr_box *dest);
 
 #endif
diff --git a/include/wlr/types/wlr_compositor.h b/include/wlr/types/wlr_compositor.h
index ceeb64ca..8481c590 100644
--- a/include/wlr/types/wlr_compositor.h
+++ b/include/wlr/types/wlr_compositor.h
@@ -13,7 +13,7 @@ struct wlr_compositor {
 	struct wl_listener display_destroy;
 
 	struct {
-		struct wl_signal create_surface;
+		struct wl_signal new_surface;
 	} events;
 };
 
diff --git a/include/wlr/types/wlr_data_device.h b/include/wlr/types/wlr_data_device.h
index 54514b4c..ff4a0f7e 100644
--- a/include/wlr/types/wlr_data_device.h
+++ b/include/wlr/types/wlr_data_device.h
@@ -71,10 +71,10 @@ struct wlr_drag_icon {
 	bool is_pointer;
 	int32_t touch_id;
 
-	int32_t sx;
-	int32_t sy;
+	int32_t sx, sy;
 
 	struct {
+		struct wl_signal map; // emitted when mapped or unmapped
 		struct wl_signal destroy;
 	} events;
 
diff --git a/include/wlr/types/wlr_output.h b/include/wlr/types/wlr_output.h
index 9df2001e..a653d527 100644
--- a/include/wlr/types/wlr_output.h
+++ b/include/wlr/types/wlr_output.h
@@ -2,6 +2,8 @@
 #define WLR_TYPES_WLR_OUTPUT_H
 
 #include <stdbool.h>
+#include <time.h>
+#include <pixman.h>
 #include <wayland-util.h>
 #include <wayland-server.h>
 
@@ -22,7 +24,6 @@ struct wlr_output_cursor {
 	struct wl_list link;
 
 	// only when using a software cursor without a surface
-	struct wlr_renderer *renderer;
 	struct wlr_texture *texture;
 
 	// only when using a cursor surface
@@ -51,22 +52,26 @@ struct wlr_output {
 	char serial[16];
 	int32_t phys_width, phys_height; // mm
 
+	// Note: some backends may have zero modes
+	struct wl_list modes;
+	struct wlr_output_mode *current_mode;
+	int32_t width, height;
+	int32_t refresh; // mHz, may be zero
+
 	bool enabled;
 	float scale;
 	enum wl_output_subpixel subpixel;
 	enum wl_output_transform transform;
-	bool needs_swap;
 
+	bool needs_swap;
+	// damage for cursors and fullscreen surface, in output-local coordinates
+	pixman_region32_t damage;
+	bool frame_pending;
 	float transform_matrix[16];
 
-	// Note: some backends may have zero modes
-	struct wl_list modes;
-	struct wlr_output_mode *current_mode;
-	int32_t width, height;
-	int32_t refresh; // mHz
-
 	struct {
 		struct wl_signal frame;
+		struct wl_signal needs_swap;
 		struct wl_signal swap_buffers;
 		struct wl_signal enable;
 		struct wl_signal mode;
@@ -75,9 +80,12 @@ struct wlr_output {
 		struct wl_signal destroy;
 	} events;
 
+	struct wl_event_source *idle_frame;
+
 	struct wlr_surface *fullscreen_surface;
 	struct wl_listener fullscreen_surface_commit;
 	struct wl_listener fullscreen_surface_destroy;
+	int fullscreen_width, fullscreen_height;
 
 	struct wl_list cursors; // wlr_output_cursor::link
 	struct wlr_output_cursor *hardware_cursor;
@@ -104,16 +112,44 @@ void wlr_output_set_transform(struct wlr_output *output,
 void wlr_output_set_position(struct wlr_output *output, int32_t lx, int32_t ly);
 void wlr_output_set_scale(struct wlr_output *output, float scale);
 void wlr_output_destroy(struct wlr_output *output);
+/**
+ * Computes the transformed output resolution.
+ */
+void wlr_output_transformed_resolution(struct wlr_output *output,
+	int *width, int *height);
+/**
+ * Computes the transformed and scaled output resolution.
+ */
 void wlr_output_effective_resolution(struct wlr_output *output,
 	int *width, int *height);
-void wlr_output_make_current(struct wlr_output *output);
-void wlr_output_swap_buffers(struct wlr_output *output);
+/**
+ * Makes the output rendering context current.
+ *
+ * `buffer_age` is set to the drawing buffer age in number of frames or -1 if
+ * unknown. This is useful for damage tracking.
+ */
+bool wlr_output_make_current(struct wlr_output *output, int *buffer_age);
+/**
+ * Swaps the output buffers. If the time of the frame isn't known, set `when` to
+ * NULL. If the compositor doesn't support damage tracking, set `damage` to
+ * NULL.
+ *
+ * Swapping buffers schedules a `frame` event.
+ */
+bool wlr_output_swap_buffers(struct wlr_output *output, struct timespec *when,
+	pixman_region32_t *damage);
+/**
+ * Manually schedules a `frame` event. If a `frame` event is already pending,
+ * it is a no-op.
+ */
+void wlr_output_schedule_frame(struct wlr_output *output);
 void wlr_output_set_gamma(struct wlr_output *output,
 	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 uint32_t wlr_output_get_gamma_size(struct wlr_output *output);
 void wlr_output_set_fullscreen_surface(struct wlr_output *output,
 	struct wlr_surface *surface);
 
+
 struct wlr_output_cursor *wlr_output_cursor_create(struct wlr_output *output);
 /**
  * Sets the cursor image. The image must be already scaled for the output.
diff --git a/include/wlr/types/wlr_seat.h b/include/wlr/types/wlr_seat.h
index c2a89f33..ffdabd98 100644
--- a/include/wlr/types/wlr_seat.h
+++ b/include/wlr/types/wlr_seat.h
@@ -209,6 +209,8 @@ struct wlr_seat {
 		struct wl_signal selection;
 		struct wl_signal primary_selection;
 
+		struct wl_signal new_drag_icon;
+
 		struct wl_signal destroy;
 	} events;
 
diff --git a/include/wlr/types/wlr_surface.h b/include/wlr/types/wlr_surface.h
index 9f88d044..50316abc 100644
--- a/include/wlr/types/wlr_surface.h
+++ b/include/wlr/types/wlr_surface.h
@@ -56,6 +56,10 @@ struct wlr_subsurface {
 	struct wl_list parent_pending_link;
 
 	struct wl_listener parent_destroy_listener;
+
+	struct {
+		struct wl_signal destroy;
+	} events;
 };
 
 struct wlr_surface {
@@ -70,6 +74,7 @@ struct wlr_surface {
 
 	struct {
 		struct wl_signal commit;
+		struct wl_signal new_subsurface;
 		struct wl_signal destroy;
 	} events;
 
diff --git a/include/wlr/types/wlr_wl_shell.h b/include/wlr/types/wlr_wl_shell.h
index 375477c7..00f2bb69 100644
--- a/include/wlr/types/wlr_wl_shell.h
+++ b/include/wlr/types/wlr_wl_shell.h
@@ -79,6 +79,7 @@ struct wlr_wl_shell_surface {
 	struct {
 		struct wl_signal destroy;
 		struct wl_signal ping_timeout;
+		struct wl_signal new_popup;
 
 		struct wl_signal request_move;
 		struct wl_signal request_resize;
diff --git a/include/wlr/types/wlr_xdg_shell_v6.h b/include/wlr/types/wlr_xdg_shell_v6.h
index 280bea27..c7b1a24b 100644
--- a/include/wlr/types/wlr_xdg_shell_v6.h
+++ b/include/wlr/types/wlr_xdg_shell_v6.h
@@ -34,6 +34,7 @@ struct wlr_xdg_client_v6 {
 
 struct wlr_xdg_popup_v6 {
 	struct wlr_xdg_surface_v6 *base;
+	struct wl_list link;
 
 	struct wl_resource *resource;
 	bool committed;
@@ -104,8 +105,7 @@ struct wlr_xdg_surface_v6 {
 		struct wlr_xdg_popup_v6 *popup_state;
 	};
 
-	struct wl_list popups;
-	struct wl_list popup_link;
+	struct wl_list popups; // wlr_xdg_popup_v6::link
 
 	bool configured;
 	bool added;
@@ -126,6 +126,7 @@ struct wlr_xdg_surface_v6 {
 	struct {
 		struct wl_signal destroy;
 		struct wl_signal ping_timeout;
+		struct wl_signal new_popup;
 
 		struct wl_signal request_maximize;
 		struct wl_signal request_fullscreen;
diff --git a/include/wlr/util/region.h b/include/wlr/util/region.h
new file mode 100644
index 00000000..7883af97
--- /dev/null
+++ b/include/wlr/util/region.h
@@ -0,0 +1,29 @@
+#ifndef WLR_UTIL_REGION_H
+#define WLR_UTIL_REGION_H
+
+#include <pixman.h>
+#include <wayland-server.h>
+
+/**
+ * Scales a region, ie. multiplies all its coordinates by `scale`.
+ *
+ * The resulting coordinates are rounded up or down so that the new region is
+ * at least as big as the original one.
+ */
+void wlr_region_scale(pixman_region32_t *dst, pixman_region32_t *src,
+	float scale);
+
+/**
+ * Applies a transform to a region inside a box of size `width` x `height`.
+ */
+void wlr_region_transform(pixman_region32_t *dst, pixman_region32_t *src,
+	enum wl_output_transform transform, int width, int height);
+
+/**
+ * Expands the region of `distance`. If `distance` is negative, it shrinks the
+ * region.
+ */
+void wlr_region_expand(pixman_region32_t *dst, pixman_region32_t *src,
+	int distance);
+
+#endif