Merge pull request #418 from acrisci/feature/wlr-seat-touch

wlr-seat: touch

backend/libinput/touch.c

@@ -33,7 +33,7 @@ void handle_touch_down(struct libinput_event *event,
 	wlr_event.device = wlr_dev;
 	wlr_event.time_msec =
 		usec_to_msec(libinput_event_touch_get_time_usec(tevent));
-	wlr_event.slot = libinput_event_touch_get_slot(tevent);
+	wlr_event.touch_id = libinput_event_touch_get_slot(tevent);
 	wlr_event.x_mm = libinput_event_touch_get_x(tevent);
 	wlr_event.y_mm = libinput_event_touch_get_y(tevent);
 	libinput_device_get_size(libinput_dev, &wlr_event.width_mm, &wlr_event.height_mm);
@@ -54,7 +54,7 @@ void handle_touch_up(struct libinput_event *event,
 	wlr_event.device = wlr_dev;
 	wlr_event.time_msec =
 		usec_to_msec(libinput_event_touch_get_time_usec(tevent));
-	wlr_event.slot = libinput_event_touch_get_slot(tevent);
+	wlr_event.touch_id = libinput_event_touch_get_slot(tevent);
 	wl_signal_emit(&wlr_dev->touch->events.up, &wlr_event);
 }
 
@@ -72,7 +72,7 @@ void handle_touch_motion(struct libinput_event *event,
 	wlr_event.device = wlr_dev;
 	wlr_event.time_msec =
 		usec_to_msec(libinput_event_touch_get_time_usec(tevent));
-	wlr_event.slot = libinput_event_touch_get_slot(tevent);
+	wlr_event.touch_id = libinput_event_touch_get_slot(tevent);
 	wlr_event.x_mm = libinput_event_touch_get_x(tevent);
 	wlr_event.y_mm = libinput_event_touch_get_y(tevent);
 	libinput_device_get_size(libinput_dev, &wlr_event.width_mm, &wlr_event.height_mm);
@@ -93,6 +93,6 @@ void handle_touch_cancel(struct libinput_event *event,
 	wlr_event.device = wlr_dev;
 	wlr_event.time_msec =
 		usec_to_msec(libinput_event_touch_get_time_usec(tevent));
-	wlr_event.slot = libinput_event_touch_get_slot(tevent);
+	wlr_event.touch_id = libinput_event_touch_get_slot(tevent);
 	wl_signal_emit(&wlr_dev->touch->events.cancel, &wlr_event);
 }

examples/pointer.c

@@ -55,7 +55,7 @@ struct sample_state {
 };
 
 struct touch_point {
-	int32_t slot;
+	int32_t touch_id;
 	double x, y;
 };
 
@@ -199,7 +199,7 @@ static void handle_touch_up(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_up *event = data;
 	for (size_t i = 0; i < sample->touch_points->length; ++i) {
 		struct touch_point *point = sample->touch_points->items[i];
-		if (point->slot == event->slot) {
+		if (point->touch_id == event->touch_id) {
 			wlr_list_del(sample->touch_points, i);
 			break;
 		}
@@ -212,7 +212,7 @@ static void handle_touch_down(struct wl_listener *listener, void *data) {
 	struct sample_state *sample = wl_container_of(listener, sample, touch_down);
 	struct wlr_event_touch_down *event = data;
 	struct touch_point *point = calloc(1, sizeof(struct touch_point));
-	point->slot = event->slot;
+	point->touch_id = event->touch_id;
 	point->x = event->x_mm / event->width_mm;
 	point->y = event->y_mm / event->height_mm;
 	if (wlr_list_add(sample->touch_points, point) == -1) {
@@ -228,7 +228,7 @@ static void handle_touch_motion(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_motion *event = data;
 	for (size_t i = 0; i < sample->touch_points->length; ++i) {
 		struct touch_point *point = sample->touch_points->items[i];
-		if (point->slot == event->slot) {
+		if (point->touch_id == event->touch_id) {
 			point->x = event->x_mm / event->width_mm;
 			point->y = event->y_mm / event->height_mm;
 			break;

examples/support/shared.c

@@ -136,7 +136,7 @@ static void touch_down_notify(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_down *event = data;
 	struct touch_state *tstate = wl_container_of(listener, tstate, down);
 	if (tstate->compositor->touch_down_cb) {
-		tstate->compositor->touch_down_cb(tstate, event->slot,
+		tstate->compositor->touch_down_cb(tstate, event->touch_id,
 			event->x_mm, event->y_mm, event->width_mm, event->height_mm);
 	}
 }
@@ -145,7 +145,7 @@ static void touch_motion_notify(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_motion *event = data;
 	struct touch_state *tstate = wl_container_of(listener, tstate, motion);
 	if (tstate->compositor->touch_motion_cb) {
-		tstate->compositor->touch_motion_cb(tstate, event->slot,
+		tstate->compositor->touch_motion_cb(tstate, event->touch_id,
 			event->x_mm, event->y_mm, event->width_mm, event->height_mm);
 	}
 }
@@ -154,7 +154,7 @@ static void touch_up_notify(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_up *event = data;
 	struct touch_state *tstate = wl_container_of(listener, tstate, up);
 	if (tstate->compositor->touch_up_cb) {
-		tstate->compositor->touch_up_cb(tstate, event->slot);
+		tstate->compositor->touch_up_cb(tstate, event->touch_id);
 	}
 }
 
@@ -162,7 +162,7 @@ static void touch_cancel_notify(struct wl_listener *listener, void *data) {
 	struct wlr_event_touch_cancel *event = data;
 	struct touch_state *tstate = wl_container_of(listener, tstate, cancel);
 	if (tstate->compositor->touch_cancel_cb) {
-		tstate->compositor->touch_cancel_cb(tstate, event->slot);
+		tstate->compositor->touch_cancel_cb(tstate, event->touch_id);
 	}
 }
 

examples/support/shared.h

@@ -95,12 +95,12 @@ struct compositor_state {
 		enum wlr_axis_source source,
 		enum wlr_axis_orientation orientation,
 		double delta);
-	void (*touch_down_cb)(struct touch_state *s, int32_t slot,
+	void (*touch_down_cb)(struct touch_state *s, int32_t touch_id,
 		double x, double y, double width, double height);
-	void (*touch_motion_cb)(struct touch_state *s, int32_t slot,
+	void (*touch_motion_cb)(struct touch_state *s, int32_t touch_id,
 		double x, double y, double width, double height);
-	void (*touch_up_cb)(struct touch_state *s, int32_t slot);
-	void (*touch_cancel_cb)(struct touch_state *s, int32_t slot);
+	void (*touch_up_cb)(struct touch_state *s, int32_t touch_id);
+	void (*touch_cancel_cb)(struct touch_state *s, int32_t touch_id);
 	void (*tool_axis_cb)(struct tablet_tool_state *s,
 			struct wlr_event_tablet_tool_axis *event);
 	void (*tool_proximity_cb)(struct tablet_tool_state *s,

examples/touch.c

@@ -28,7 +28,7 @@ struct sample_state {
 };
 
 struct touch_point {
-	int32_t slot;
+	int32_t touch_id;
 	double x, y;
 };
 
@@ -58,11 +58,11 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 	wlr_output_swap_buffers(wlr_output);
 }
 
-static void handle_touch_down(struct touch_state *tstate, int32_t slot,
+static void handle_touch_down(struct touch_state *tstate, int32_t touch_id,
 		double x, double y, double width, double height) {
 	struct sample_state *sample = tstate->compositor->data;
 	struct touch_point *point = calloc(1, sizeof(struct touch_point));
-	point->slot = slot;
+	point->touch_id = touch_id;
 	point->x = x / width;
 	point->y = y / height;
 	if (wlr_list_add(sample->touch_points, point) == -1) {
@@ -70,23 +70,23 @@ static void handle_touch_down(struct touch_state *tstate, int32_t slot,
 	}
 }
 
-static void handle_touch_up(struct touch_state *tstate, int32_t slot) {
+static void handle_touch_up(struct touch_state *tstate, int32_t touch_id) {
 	struct sample_state *sample = tstate->compositor->data;
 	for (size_t i = 0; i < sample->touch_points->length; ++i) {
 		struct touch_point *point = sample->touch_points->items[i];
-		if (point->slot == slot) {
+		if (point->touch_id == touch_id) {
 			wlr_list_del(sample->touch_points, i);
 			break;
 		}
 	}
 }
 
-static void handle_touch_motion(struct touch_state *tstate, int32_t slot,
+static void handle_touch_motion(struct touch_state *tstate, int32_t touch_id,
 		double x, double y, double width, double height) {
 	struct sample_state *sample = tstate->compositor->data;
 	for (size_t i = 0; i < sample->touch_points->length; ++i) {
 		struct touch_point *point = sample->touch_points->items[i];
-		if (point->slot == slot) {
+		if (point->touch_id == touch_id) {
 			point->x = x / width;
 			point->y = y / height;
 			break;

include/rootston/cursor.h

@@ -39,7 +39,6 @@ struct roots_cursor {
 	uint32_t resize_edges;
 	// Ring buffer of input events that could trigger move/resize/rotate
 	int input_events_idx;
-	struct wl_list touch_points;
 	struct roots_input_event input_events[16];
 
 	struct wl_listener motion;
@@ -57,6 +56,9 @@ struct roots_cursor {
 	struct wl_listener pointer_grab_begin;
 	struct wl_listener pointer_grab_end;
 
+	struct wl_listener touch_grab_begin;
+	struct wl_listener touch_grab_end;
+
 	struct wl_listener request_set_cursor;
 };
 
@@ -100,4 +102,10 @@ void roots_cursor_handle_pointer_grab_begin(struct roots_cursor *cursor,
 void roots_cursor_handle_pointer_grab_end(struct roots_cursor *cursor,
 		struct wlr_seat_pointer_grab *grab);
 
+void roots_cursor_handle_touch_grab_begin(struct roots_cursor *cursor,
+		struct wlr_seat_touch_grab *grab);
+
+void roots_cursor_handle_touch_grab_end(struct roots_cursor *cursor,
+		struct wlr_seat_touch_grab *grab);
+
 #endif

include/rootston/seat.h

@@ -9,6 +9,9 @@ struct roots_drag_icon {
 	struct wl_list link; // roots_seat::drag_icons
 	bool mapped;
 
+	bool is_pointer;
+	int32_t touch_id;
+
 	int32_t sx;
 	int32_t sy;
 
@@ -23,6 +26,10 @@ struct roots_seat {
 	struct wl_list link;
 	struct wl_list drag_icons;
 
+	// coordinates of the first touch point if it exists
+	int32_t touch_id;
+	double touch_x, touch_y;
+
 	struct roots_view *focus;
 
 	struct wl_list keyboards;
@@ -43,13 +50,6 @@ struct roots_touch {
 	struct wl_list link;
 };
 
-struct roots_touch_point {
-	struct roots_touch *device;
-	int32_t slot;
-	double x, y;
-	struct wl_list link;
-};
-
 struct roots_tablet_tool {
 	struct roots_seat *seat;
 	struct wlr_input_device *device;

include/wlr/types/wlr_cursor.h

@@ -126,4 +126,11 @@ void wlr_cursor_map_to_region(struct wlr_cursor *cur, struct wlr_box *box);
 void wlr_cursor_map_input_to_region(struct wlr_cursor *cur,
 	struct wlr_input_device *dev, struct wlr_box *box);
 
+/**
+ * Convert absolute coordinates to layout coordinates for the device.
+ */
+bool wlr_cursor_absolute_to_layout_coords(struct wlr_cursor *cur,
+		struct wlr_input_device *device, double x_mm, double y_mm,
+		double width_mm, double height_mm, double *lx, double *ly);
+
 #endif

include/wlr/types/wlr_data_device.h

@@ -10,6 +10,9 @@ wlr_pointer_grab_interface wlr_data_device_pointer_drag_interface;
 extern const struct
 wlr_keyboard_grab_interface wlr_data_device_keyboard_drag_interface;
 
+extern const struct
+wlr_touch_grab_interface wlr_data_device_touch_drag_interface;
+
 struct wlr_data_device_manager {
 	struct wl_global *global;
 };
@@ -53,16 +56,22 @@ struct wlr_data_source {
 struct wlr_drag {
 	struct wlr_seat_pointer_grab pointer_grab;
 	struct wlr_seat_keyboard_grab keyboard_grab;
+	struct wlr_seat_touch_grab touch_grab;
 
+	struct wlr_seat *seat;
 	struct wlr_seat_client *seat_client;
 	struct wlr_seat_client *focus_client;
 
+	bool is_pointer_grab;
+
 	struct wlr_surface *icon;
 	struct wlr_surface *focus;
 	struct wlr_data_source *source;
 
 	bool cancelling;
+	int32_t grab_touch_id;
 
+	struct wl_listener point_destroy;
 	struct wl_listener icon_destroy;
 	struct wl_listener source_destroy;
 	struct wl_listener seat_client_unbound;

include/wlr/types/wlr_seat.h

@@ -24,6 +24,26 @@ struct wlr_seat_client {
 	struct wl_list link;
 };
 
+struct wlr_touch_point {
+	int32_t touch_id;
+	struct wlr_surface *surface;
+	struct wlr_seat_client *client;
+
+	struct wlr_surface *focus_surface;
+	struct wlr_seat_client *focus_client;
+	double sx, sy;
+
+	struct wl_listener surface_destroy;
+	struct wl_listener focus_surface_destroy;
+	struct wl_listener resource_destroy;
+
+	struct {
+		struct wl_signal destroy;
+	} events;
+
+	struct wl_list link;
+};
+
 struct wlr_seat_pointer_grab;
 
 struct wlr_pointer_grab_interface {
@@ -49,6 +69,32 @@ struct wlr_keyboard_grab_interface {
 	void (*cancel)(struct wlr_seat_keyboard_grab *grab);
 };
 
+struct wlr_seat_touch_grab;
+
+struct wlr_touch_grab_interface {
+	uint32_t (*down)(struct wlr_seat_touch_grab *grab, uint32_t time,
+			struct wlr_touch_point *point);
+	void (*up)(struct wlr_seat_touch_grab *grab, uint32_t time,
+			struct wlr_touch_point *point);
+	void (*motion)(struct wlr_seat_touch_grab *grab, uint32_t time,
+			struct wlr_touch_point *point);
+	void (*enter)(struct wlr_seat_touch_grab *grab, uint32_t time,
+			struct wlr_touch_point *point);
+	// XXX this will conflict with the actual touch cancel which is different so
+	// we need to rename this
+	void (*cancel)(struct wlr_seat_touch_grab *grab);
+};
+
+/**
+ * Passed to `wlr_seat_touch_start_grab()` to start a grab of the touch device.
+ * The grabber is responsible for handling touch events for the seat.
+ */
+struct wlr_seat_touch_grab {
+	const struct wlr_touch_grab_interface *interface;
+	struct wlr_seat *seat;
+	void *data;
+};
+
 /**
  * Passed to `wlr_seat_keyboard_start_grab()` to start a grab of the keyboard.
  * The grabber is responsible for handling keyboard events for the seat.
@@ -86,6 +132,7 @@ struct wlr_seat_pointer_state {
 	struct wl_listener resource_destroy;
 };
 
+// TODO: May be useful to be able to simulate keyboard input events
 struct wlr_seat_keyboard_state {
 	struct wlr_seat *seat;
 	struct wlr_keyboard *keyboard;
@@ -103,6 +150,17 @@ struct wlr_seat_keyboard_state {
 	struct wlr_seat_keyboard_grab *default_grab;
 };
 
+struct wlr_seat_touch_state {
+	struct wlr_seat *seat;
+	struct wl_list touch_points; // wlr_touch_point::link
+
+	uint32_t grab_serial;
+	uint32_t grab_id;
+
+	struct wlr_seat_touch_grab *grab;
+	struct wlr_seat_touch_grab *default_grab;
+};
+
 struct wlr_seat {
 	struct wl_global *wl_global;
 	struct wl_display *display;
@@ -117,6 +175,7 @@ struct wlr_seat {
 
 	struct wlr_seat_pointer_state pointer_state;
 	struct wlr_seat_keyboard_state keyboard_state;
+	struct wlr_seat_touch_state touch_state;
 
 	struct wl_listener selection_data_source_destroy;
 
@@ -130,6 +189,9 @@ struct wlr_seat {
 		struct wl_signal keyboard_grab_begin;
 		struct wl_signal keyboard_grab_end;
 
+		struct wl_signal touch_grab_begin;
+		struct wl_signal touch_grab_end;
+
 		struct wl_signal request_set_cursor;
 
 		struct wl_signal selection;
@@ -259,6 +321,11 @@ uint32_t wlr_seat_pointer_notify_button(struct wlr_seat *wlr_seat,
 void wlr_seat_pointer_notify_axis(struct wlr_seat *wlr_seat, uint32_t time,
 		enum wlr_axis_orientation orientation, double value);
 
+/**
+ * Whether or not the pointer has a grab other than the default grab.
+ */
+bool wlr_seat_pointer_has_grab(struct wlr_seat *seat);
+
 /**
  * Set this keyboard as the active keyboard for the seat.
  */
@@ -326,6 +393,108 @@ void wlr_seat_keyboard_enter(struct wlr_seat *wlr_seat,
  */
 void wlr_seat_keyboard_clear_focus(struct wlr_seat *wlr_seat);
 
-// TODO: May be useful to be able to simulate keyboard input events
+/**
+ * Whether or not the keyboard has a grab other than the default grab
+ */
+bool wlr_seat_keyboard_has_grab(struct wlr_seat *seat);
+
+/**
+ * Start a grab of the touch device of this seat. The grabber is responsible for
+ * handling all touch events until the grab ends.
+ */
+void wlr_seat_touch_start_grab(struct wlr_seat *wlr_seat,
+		struct wlr_seat_touch_grab *grab);
+
+/**
+ * End the grab of the touch device of this seat. This reverts the grab back to
+ * the default grab for the touch device.
+ */
+void wlr_seat_touch_end_grab(struct wlr_seat *wlr_seat);
+
+/**
+ * Get the active touch point with the given `touch_id`. If the touch point does
+ * not exist or is no longer active, returns NULL.
+ */
+struct wlr_touch_point *wlr_seat_touch_get_point(struct wlr_seat *seat,
+		int32_t touch_id);
+
+/**
+ * Notify the seat of a touch down on the given surface. Defers to any grab of
+ * the touch device.
+ */
+uint32_t wlr_seat_touch_notify_down(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy);
+
+/**
+ * Notify the seat that the touch point given by `touch_id` is up. Defers to any
+ * grab of the touch device.
+ */
+void wlr_seat_touch_notify_up(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id);
+
+/**
+ * Notify the seat that the touch point given by `touch_id` has moved. Defers to
+ * any grab of the touch device. The seat should be notified of touch motion
+ * even if the surface is not the owner of the touch point for processing by
+ * grabs.
+ */
+void wlr_seat_touch_notify_motion(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id, double sx, double sy);
+
+/**
+ * Notify the seat that the touch point given by `touch_id` has entered a new
+ * surface. The surface is required. To clear focus, use
+ * `wlr_seat_touch_point_clear_focus()`.
+ */
+void wlr_seat_touch_point_focus(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy);
+
+/**
+ * Clear the focused surface for the touch point given by `touch_id`.
+ */
+void wlr_seat_touch_point_clear_focus(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id);
+
+/**
+ * Send a touch down event to the client of the given surface. All future touch
+ * events for this point will go to this surface. If the touch down is valid,
+ * this will add a new touch point with the given `touch_id`. The touch down may
+ * not be valid if the surface seat client does not accept touch input.
+ * Coordinates are surface-local. Compositors should use
+ * `wlr_seat_touch_notify_down()` to respect any grabs of the touch device.
+ */
+uint32_t wlr_seat_touch_send_down(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy);
+
+/**
+ * Send a touch up event for the touch point given by the `touch_id`. The event
+ * will go to the client for the surface given in the cooresponding touch down
+ * event. This will remove the touch point. Compositors should use
+ * `wlr_seat_touch_notify_up()` to respect any grabs of the touch device.
+ */
+void wlr_seat_touch_send_up(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id);
+
+/**
+ * Send a touch motion event for the touch point given by the `touch_id`. The
+ * event will go to the client for the surface given in the corresponding touch
+ * down event. Compositors should use `wlr_seat_touch_notify_motion()` to
+ * respect any grabs of the touch device.
+ */
+void wlr_seat_touch_send_motion(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id, double sx, double sy);
+
+/**
+ * How many touch points are currently down for the seat.
+ */
+int wlr_seat_touch_num_points(struct wlr_seat *seat);
+
+/**
+ * Whether or not the seat has a touch grab other than the default grab.
+ */
+bool wlr_seat_touch_has_grab(struct wlr_seat *seat);
 
 #endif

include/wlr/types/wlr_touch.h

@@ -22,7 +22,7 @@ struct wlr_touch {
 struct wlr_event_touch_down {
 	struct wlr_input_device *device;
 	uint32_t time_msec;
-	int32_t slot;
+	int32_t touch_id;
 	double x_mm, y_mm;
 	double width_mm, height_mm;
 };
@@ -30,13 +30,13 @@ struct wlr_event_touch_down {
 struct wlr_event_touch_up {
 	struct wlr_input_device *device;
 	uint32_t time_msec;
-	int32_t slot;
+	int32_t touch_id;
 };
 
 struct wlr_event_touch_motion {
 	struct wlr_input_device *device;
 	uint32_t time_msec;
-	int32_t slot;
+	int32_t touch_id;
 	double x_mm, y_mm;
 	double width_mm, height_mm;
 };
@@ -44,7 +44,7 @@ struct wlr_event_touch_motion {
 struct wlr_event_touch_cancel {
 	struct wlr_input_device *device;
 	uint32_t time_msec;
-	int32_t slot;
+	int32_t touch_id;
 };
 
 #endif

rootston/cursor.c

@@ -28,7 +28,8 @@ void roots_cursor_destroy(struct roots_cursor *cursor) {
 	// TODO
 }
 
-static void roots_cursor_update_position(struct roots_cursor *cursor, uint32_t time) {
+static void roots_cursor_update_position(struct roots_cursor *cursor,
+		uint32_t time) {
 	struct roots_desktop *desktop = cursor->seat->input->server->desktop;
 	struct roots_seat *seat = cursor->seat;
 	struct roots_view *view;
@@ -128,15 +129,18 @@ static void roots_cursor_update_position(struct roots_cursor *cursor, uint32_t t
 
 static void roots_cursor_press_button(struct roots_cursor *cursor,
 		struct wlr_input_device *device, uint32_t time, uint32_t button,
-		uint32_t state) {
+		uint32_t state, double lx, double ly) {
 	struct roots_seat *seat = cursor->seat;
 	struct roots_desktop *desktop = seat->input->server->desktop;
+	bool is_touch = device->type == WLR_INPUT_DEVICE_TOUCH;
+
 	struct wlr_surface *surface;
 	double sx, sy;
-	struct roots_view *view = view_at(desktop,
-		cursor->cursor->x, cursor->cursor->y, &surface, &sx, &sy);
+	struct roots_view *view = view_at(desktop, lx, ly, &surface, &sx, &sy);
 
-	if (state == WLR_BUTTON_PRESSED && view && roots_seat_has_meta_pressed(seat)) {
+	if (state == WLR_BUTTON_PRESSED &&
+			view &&
+			roots_seat_has_meta_pressed(seat)) {
 		roots_seat_focus_view(seat, view);
 
 		uint32_t edges;
@@ -165,14 +169,21 @@ static void roots_cursor_press_button(struct roots_cursor *cursor,
 		return;
 	}
 
-	uint32_t serial =
+	uint32_t serial;
+	if (is_touch) {
+		serial = wl_display_get_serial(desktop->server->wl_display);
+	} else {
+		serial =
 			wlr_seat_pointer_notify_button(seat->seat, time, button, state);
+	}
 
 	int i;
 	switch (state) {
 	case WLR_BUTTON_RELEASED:
 		seat->cursor->mode = ROOTS_CURSOR_PASSTHROUGH;
+		if (!is_touch) {
 			roots_cursor_update_position(cursor, time);
+		}
 		break;
 	case WLR_BUTTON_PRESSED:
 		i = cursor->input_events_idx;
@@ -203,7 +214,7 @@ void roots_cursor_handle_motion_absolute(struct roots_cursor *cursor,
 void roots_cursor_handle_button(struct roots_cursor *cursor,
 		struct wlr_event_pointer_button *event) {
 	roots_cursor_press_button(cursor, event->device, event->time_msec,
-		event->button, event->state);
+		event->button, event->state, cursor->cursor->x, cursor->cursor->y);
 }
 
 void roots_cursor_handle_axis(struct roots_cursor *cursor,
@@ -214,50 +225,86 @@ void roots_cursor_handle_axis(struct roots_cursor *cursor,
 
 void roots_cursor_handle_touch_down(struct roots_cursor *cursor,
 		struct wlr_event_touch_down *event) {
-	struct roots_touch_point *point =
-		calloc(1, sizeof(struct roots_touch_point));
-	if (!point) {
-		wlr_log(L_ERROR, "could not allocate memory for touch point");
+	struct roots_desktop *desktop = cursor->seat->input->server->desktop;
+	struct wlr_surface *surface = NULL;
+	double lx, ly;
+	bool result =
+		wlr_cursor_absolute_to_layout_coords(cursor->cursor,
+			event->device, event->x_mm, event->y_mm, event->width_mm,
+			event->height_mm, &lx, &ly);
+	if (!result) {
 		return;
 	}
+	double sx, sy;
+	view_at(desktop, lx, ly, &surface, &sx, &sy);
 
-	point->device = event->device->data;
-	point->slot = event->slot;
-	point->x = event->x_mm / event->width_mm;
-	point->y = event->y_mm / event->height_mm;
-	wlr_cursor_warp_absolute(cursor->cursor, event->device, point->x, point->y);
-	roots_cursor_update_position(cursor, event->time_msec);
-	wl_list_insert(&cursor->touch_points, &point->link);
-	roots_cursor_press_button(cursor,  event->device,
-		event->time_msec, BTN_LEFT, 1);
+	uint32_t serial = 0;
+	if (surface) {
+		serial = wlr_seat_touch_notify_down(cursor->seat->seat, surface,
+			event->time_msec, event->touch_id, sx, sy);
+	}
+
+	if (serial && wlr_seat_touch_num_points(cursor->seat->seat) == 1) {
+		cursor->seat->touch_id = event->touch_id;
+		cursor->seat->touch_x = lx;
+		cursor->seat->touch_y = ly;
+		roots_cursor_press_button(cursor, event->device, event->time_msec,
+			BTN_LEFT, 1, lx, ly);
+	}
 }
 
 void roots_cursor_handle_touch_up(struct roots_cursor *cursor,
 		struct wlr_event_touch_up *event) {
-	struct roots_touch_point *point;
-	wl_list_for_each(point, &cursor->touch_points, link) {
-		if (point->slot == event->slot) {
-			wl_list_remove(&point->link);
-			free(point);
-			break;
+	struct wlr_touch_point *point =
+		wlr_seat_touch_get_point(cursor->seat->seat, event->touch_id);
+	if (!point) {
+		return;
 	}
+
+	if (wlr_seat_touch_num_points(cursor->seat->seat) == 1) {
+		roots_cursor_press_button(cursor, event->device, event->time_msec,
+			BTN_LEFT, 0, cursor->seat->touch_x, cursor->seat->touch_y);
 	}
-	roots_cursor_press_button(cursor, event->device,
-		event->time_msec, BTN_LEFT, 0);
+
+	wlr_seat_touch_notify_up(cursor->seat->seat, event->time_msec,
+		event->touch_id);
 }
 
 void roots_cursor_handle_touch_motion(struct roots_cursor *cursor,
 		struct wlr_event_touch_motion *event) {
-	struct roots_touch_point *point;
-	wl_list_for_each(point, &cursor->touch_points, link) {
-		if (point->slot == event->slot) {
-			point->x = event->x_mm / event->width_mm;
-			point->y = event->y_mm / event->height_mm;
-			wlr_cursor_warp_absolute(cursor->cursor, event->device,
-					point->x, point->y);
-			roots_cursor_update_position(cursor, event->time_msec);
-			break;
+	struct roots_desktop *desktop = cursor->seat->input->server->desktop;
+	struct wlr_touch_point *point =
+		wlr_seat_touch_get_point(cursor->seat->seat, event->touch_id);
+	if (!point) {
+		return;
+	}
+
+	struct wlr_surface *surface = NULL;
+	double lx, ly;
+	bool result =
+		wlr_cursor_absolute_to_layout_coords(cursor->cursor,
+			event->device, event->x_mm, event->y_mm, event->width_mm,
+			event->height_mm, &lx, &ly);
+	if (!result) {
+		return;
+	}
+
+	double sx, sy;
+	view_at(desktop, lx, ly, &surface, &sx, &sy);
+
+	if (surface) {
+		wlr_seat_touch_point_focus(cursor->seat->seat, surface,
+			event->time_msec, event->touch_id, sx, sy);
+		wlr_seat_touch_notify_motion(cursor->seat->seat, event->time_msec,
+			event->touch_id, sx, sy);
+	} else {
+		wlr_seat_touch_point_clear_focus(cursor->seat->seat, event->time_msec,
+			event->touch_id);
 	}
+
+	if (event->touch_id == cursor->seat->touch_id) {
+		cursor->seat->touch_x = lx;
+		cursor->seat->touch_y = ly;
 	}
 }
 
@@ -282,14 +329,16 @@ void roots_cursor_handle_tool_axis(struct roots_cursor *cursor,
 void roots_cursor_handle_tool_tip(struct roots_cursor *cursor,
 		struct wlr_event_tablet_tool_tip *event) {
 	roots_cursor_press_button(cursor, event->device,
-		event->time_msec, BTN_LEFT, event->state);
+		event->time_msec, BTN_LEFT, event->state, cursor->cursor->x,
+		cursor->cursor->y);
 }
 
 void roots_cursor_handle_request_set_cursor(struct roots_cursor *cursor,
 		struct wlr_seat_pointer_request_set_cursor_event *event) {
 	struct wlr_surface *focused_surface =
 		event->seat_client->seat->pointer_state.focused_surface;
-	bool has_focused = focused_surface != NULL && focused_surface->resource != NULL;
+	bool has_focused =
+		focused_surface != NULL && focused_surface->resource != NULL;
 	struct wl_client *focused_client = NULL;
 	if (has_focused) {
 		focused_client = wl_resource_get_client(focused_surface->resource);
@@ -322,33 +371,59 @@ static void handle_drag_icon_destroy(struct wl_listener *listener, void *data) {
 	free(drag_icon);
 }
 
-void roots_cursor_handle_pointer_grab_begin(struct roots_cursor *cursor,
-		struct wlr_seat_pointer_grab *grab) {
-	struct roots_seat *seat = cursor->seat;
-	if (grab->interface == &wlr_data_device_pointer_drag_interface) {
-		struct wlr_drag *drag = grab->data;
-		if (drag->icon) {
+static struct roots_drag_icon *seat_add_drag_icon(struct roots_seat *seat,
+		struct wlr_surface *icon_surface) {
+	if (!icon_surface) {
+		return NULL;
+	}
+
 	struct roots_drag_icon *iter_icon;
 	wl_list_for_each(iter_icon, &seat->drag_icons, link) {
-				if (iter_icon->surface == drag->icon) {
+		if (iter_icon->surface == icon_surface) {
 			// already in the list
-					return;
+			return iter_icon;
 		}
 	}
 
 	struct roots_drag_icon *drag_icon =
 		calloc(1, sizeof(struct roots_drag_icon));
 	drag_icon->mapped = true;
-			drag_icon->surface = drag->icon;
+	drag_icon->surface = icon_surface;
 	wl_list_insert(&seat->drag_icons, &drag_icon->link);
 
-			wl_signal_add(&drag->icon->events.destroy,
+	wl_signal_add(&icon_surface->events.destroy,
 			&drag_icon->surface_destroy);
 	drag_icon->surface_destroy.notify = handle_drag_icon_destroy;
 
-			wl_signal_add(&drag->icon->events.commit,
+	wl_signal_add(&icon_surface->events.commit,
 			&drag_icon->surface_commit);
 	drag_icon->surface_commit.notify = handle_drag_icon_commit;
+
+	return drag_icon;
+}
+
+static void seat_unmap_drag_icon(struct roots_seat *seat,
+		struct wlr_surface *icon_surface) {
+	if (!icon_surface) {
+		return;
+	}
+
+	struct roots_drag_icon *icon;
+	wl_list_for_each(icon, &seat->drag_icons, link) {
+		if (icon->surface == icon_surface) {
+			icon->mapped = false;
+		}
+	}
+}
+
+void roots_cursor_handle_pointer_grab_begin(struct roots_cursor *cursor,
+		struct wlr_seat_pointer_grab *grab) {
+	if (grab->interface == &wlr_data_device_pointer_drag_interface) {
+		struct wlr_drag *drag = grab->data;
+		struct roots_drag_icon *icon =
+			seat_add_drag_icon(cursor->seat, drag->icon);
+		if (icon) {
+			icon->is_pointer = true;
 		}
 	}
 }
@@ -357,13 +432,27 @@ void roots_cursor_handle_pointer_grab_end(struct roots_cursor *cursor,
 		struct wlr_seat_pointer_grab *grab) {
 	if (grab->interface == &wlr_data_device_pointer_drag_interface) {
 		struct wlr_drag *drag = grab->data;
-		struct roots_drag_icon *icon;
-		wl_list_for_each(icon, &cursor->seat->drag_icons, link) {
-			if (icon->surface == drag->icon) {
-				icon->mapped = false;
+		seat_unmap_drag_icon(cursor->seat, drag->icon);
+	}
+}
+
+void roots_cursor_handle_touch_grab_begin(struct roots_cursor *cursor,
+		struct wlr_seat_touch_grab *grab) {
+	if (grab->interface == &wlr_data_device_touch_drag_interface) {
+		struct wlr_drag *drag = grab->data;
+		struct roots_drag_icon *icon =
+			seat_add_drag_icon(cursor->seat, drag->icon);
+		if (icon) {
+			icon->is_pointer = false;
+			icon->touch_id = drag->grab_touch_id;
 		}
 	}
 }
 
-	roots_cursor_update_position(cursor, 0);
+void roots_cursor_handle_touch_grab_end(struct roots_cursor *cursor,
+		struct wlr_seat_touch_grab *grab) {
+	if (grab->interface == &wlr_data_device_touch_drag_interface) {
+		struct wlr_drag *drag = grab->data;
+		seat_unmap_drag_icon(cursor->seat, drag->icon);
+	}
 }

rootston/output.c

@@ -200,9 +200,20 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 			}
 			struct wlr_surface *icon = drag_icon->surface;
 			struct wlr_cursor *cursor = seat->cursor->cursor;
-			double icon_x = cursor->x + drag_icon->sx;
-			double icon_y = cursor->y + drag_icon->sy;
+			double icon_x = 0, icon_y = 0;
+			if (drag_icon->is_pointer) {
+				icon_x = cursor->x + drag_icon->sx;
+				icon_y = cursor->y + drag_icon->sy;
 				render_surface(icon, desktop, wlr_output, &now, icon_x, icon_y, 0);
+			} else {
+				struct wlr_touch_point *point =
+					wlr_seat_touch_get_point(seat->seat, drag_icon->touch_id);
+				if (point) {
+					icon_x = seat->touch_x + drag_icon->sx;
+					icon_y = seat->touch_y + drag_icon->sy;
+					render_surface(icon, desktop, wlr_output, &now, icon_x, icon_y, 0);
+				}
+			}
 		}
 	}
 

rootston/seat.c

@@ -31,7 +31,8 @@ static void handle_cursor_motion(struct wl_listener *listener, void *data) {
 	roots_cursor_handle_motion(cursor, event);
 }
 
-static void handle_cursor_motion_absolute(struct wl_listener *listener, void *data) {
+static void handle_cursor_motion_absolute(struct wl_listener *listener,
+		void *data) {
 	struct roots_cursor *cursor =
 		wl_container_of(listener, cursor, motion_absolute);
 	struct wlr_event_pointer_motion_absolute *event = data;
@@ -111,7 +112,24 @@ static void handle_pointer_grab_end(struct wl_listener *listener,
 	roots_cursor_handle_pointer_grab_end(cursor, grab);
 }
 
-static void seat_reset_device_mappings(struct roots_seat *seat, struct wlr_input_device *device) {
+static void handle_touch_grab_begin(struct wl_listener *listener,
+		void *data) {
+	struct roots_cursor *cursor =
+		wl_container_of(listener, cursor, touch_grab_begin);
+	struct wlr_seat_touch_grab *grab = data;
+	roots_cursor_handle_touch_grab_begin(cursor, grab);
+}
+
+static void handle_touch_grab_end(struct wl_listener *listener,
+		void *data) {
+	struct roots_cursor *cursor =
+		wl_container_of(listener, cursor, touch_grab_end);
+	struct wlr_seat_touch_grab *grab = data;
+	roots_cursor_handle_touch_grab_end(cursor, grab);
+}
+
+static void seat_reset_device_mappings(struct roots_seat *seat,
+		struct wlr_input_device *device) {
 	struct wlr_cursor *cursor = seat->cursor->cursor;
 	struct roots_config *config = seat->input->config;
 
@@ -194,8 +212,6 @@ static void roots_seat_init_cursor(struct roots_seat *seat) {
 	struct roots_desktop *desktop = seat->input->server->desktop;
 	wlr_cursor_attach_output_layout(wlr_cursor, desktop->layout);
 
-	wl_list_init(&seat->cursor->touch_points);
-
 	roots_seat_configure_cursor(seat);
 	roots_seat_configure_xcursor(seat);
 
@@ -219,10 +235,12 @@ static void roots_seat_init_cursor(struct roots_seat *seat) {
 	wl_signal_add(&wlr_cursor->events.touch_up, &seat->cursor->touch_up);
 	seat->cursor->touch_up.notify = handle_touch_up;
 
-	wl_signal_add(&wlr_cursor->events.touch_motion, &seat->cursor->touch_motion);
+	wl_signal_add(&wlr_cursor->events.touch_motion,
+		&seat->cursor->touch_motion);
 	seat->cursor->touch_motion.notify = handle_touch_motion;
 
-	wl_signal_add(&wlr_cursor->events.tablet_tool_axis, &seat->cursor->tool_axis);
+	wl_signal_add(&wlr_cursor->events.tablet_tool_axis,
+		&seat->cursor->tool_axis);
 	seat->cursor->tool_axis.notify = handle_tool_axis;
 
 	wl_signal_add(&wlr_cursor->events.tablet_tool_tip, &seat->cursor->tool_tip);
@@ -239,6 +257,14 @@ static void roots_seat_init_cursor(struct roots_seat *seat) {
 	wl_signal_add(&seat->seat->events.pointer_grab_end,
 			&seat->cursor->pointer_grab_end);
 	seat->cursor->pointer_grab_end.notify = handle_pointer_grab_end;
+
+	wl_signal_add(&seat->seat->events.touch_grab_begin,
+			&seat->cursor->touch_grab_begin);
+	seat->cursor->touch_grab_begin.notify = handle_touch_grab_begin;
+
+	wl_signal_add(&seat->seat->events.touch_grab_end,
+			&seat->cursor->touch_grab_end);
+	seat->cursor->touch_grab_end.notify = handle_touch_grab_end;
 }
 
 struct roots_seat *roots_seat_create(struct roots_input *input, char *name) {
@@ -282,9 +308,11 @@ void roots_seat_destroy(struct roots_seat *seat) {
 	// TODO
 }
 
-static void seat_add_keyboard(struct roots_seat *seat, struct wlr_input_device *device) {
+static void seat_add_keyboard(struct roots_seat *seat,
+		struct wlr_input_device *device) {
 	assert(device->type == WLR_INPUT_DEVICE_KEYBOARD);
-	struct roots_keyboard *keyboard = roots_keyboard_create(device, seat->input);
+	struct roots_keyboard *keyboard =
+		roots_keyboard_create(device, seat->input);
 	if (keyboard == NULL) {
 		wlr_log(L_ERROR, "could not allocate keyboard for seat");
 		return;
@@ -305,7 +333,8 @@ static void seat_add_keyboard(struct roots_seat *seat, struct wlr_input_device *
 	wlr_seat_set_keyboard(seat->seat, device);
 }
 
-static void seat_add_pointer(struct roots_seat *seat, struct wlr_input_device *device) {
+static void seat_add_pointer(struct roots_seat *seat,
+		struct wlr_input_device *device) {
 	struct roots_pointer *pointer = calloc(sizeof(struct roots_pointer), 1);
 	if (!pointer) {
 		wlr_log(L_ERROR, "could not allocate pointer for seat");
@@ -320,7 +349,8 @@ static void seat_add_pointer(struct roots_seat *seat, struct wlr_input_device *d
 	roots_seat_configure_cursor(seat);
 }
 
-static void seat_add_touch(struct roots_seat *seat, struct wlr_input_device *device) {
+static void seat_add_touch(struct roots_seat *seat,
+		struct wlr_input_device *device) {
 	struct roots_touch *touch = calloc(sizeof(struct roots_touch), 1);
 	if (!touch) {
 		wlr_log(L_ERROR, "could not allocate touch for seat");
@@ -335,12 +365,15 @@ static void seat_add_touch(struct roots_seat *seat, struct wlr_input_device *dev
 	roots_seat_configure_cursor(seat);
 }
 
-static void seat_add_tablet_pad(struct roots_seat *seat, struct wlr_input_device *device) {
+static void seat_add_tablet_pad(struct roots_seat *seat,
+		struct wlr_input_device *device) {
 	// TODO
 }
 
-static void seat_add_tablet_tool(struct roots_seat *seat, struct wlr_input_device *device) {
-	struct roots_tablet_tool *tablet_tool = calloc(sizeof(struct roots_tablet_tool), 1);
+static void seat_add_tablet_tool(struct roots_seat *seat,
+		struct wlr_input_device *device) {
+	struct roots_tablet_tool *tablet_tool =
+		calloc(sizeof(struct roots_tablet_tool), 1);
 	if (!tablet_tool) {
 		wlr_log(L_ERROR, "could not allocate tablet_tool for seat");
 		return;

types/wlr_cursor.c

@@ -637,3 +637,21 @@ void wlr_cursor_map_input_to_region(struct wlr_cursor *cur,
 
 	c_device->mapped_box = box;
 }
+
+bool wlr_cursor_absolute_to_layout_coords(struct wlr_cursor *cur,
+		struct wlr_input_device *device, double x_mm, double y_mm,
+		double width_mm, double height_mm, double *lx, double *ly) {
+	if (width_mm <= 0 || height_mm <= 0) {
+		return false;
+	}
+
+	struct wlr_box *mapping = get_mapping(cur, device);
+	if (!mapping) {
+		mapping = wlr_output_layout_get_box(cur->state->layout, NULL);
+	}
+
+	*lx = x_mm > 0 ? mapping->width * (x_mm / width_mm) + mapping->x : cur->x;
+	*ly = y_mm > 0 ? mapping->height * (y_mm / height_mm) + mapping->y : cur->y;
+
+	return true;
+}

types/wlr_data_device.c

@@ -275,7 +275,8 @@ void wlr_seat_client_send_selection(struct wlr_seat_client *seat_client) {
 		struct wlr_data_offer *offer =
 			wlr_data_source_send_offer(seat_client->seat->selection_source,
 				seat_client->data_device);
-		wl_data_device_send_selection(seat_client->data_device, offer->resource);
+		wl_data_device_send_selection(seat_client->data_device,
+			offer->resource);
 	} else {
 		wl_data_device_send_selection(seat_client->data_device, NULL);
 	}
@@ -437,8 +438,12 @@ static void wlr_drag_set_focus(struct wlr_drag *drag,
 static void wlr_drag_end(struct wlr_drag *drag) {
 	if (!drag->cancelling) {
 		drag->cancelling = true;
-		wlr_seat_pointer_end_grab(drag->pointer_grab.seat);
-		wlr_seat_keyboard_end_grab(drag->keyboard_grab.seat);
+		if (drag->is_pointer_grab) {
+			wlr_seat_pointer_end_grab(drag->seat);
+		} else {
+			wlr_seat_touch_end_grab(drag->seat);
+		}
+		wlr_seat_keyboard_end_grab(drag->seat);
 
 		if (drag->source) {
 			wl_list_remove(&drag->source_destroy.link);
@@ -521,6 +526,54 @@ wlr_pointer_grab_interface wlr_data_device_pointer_drag_interface = {
 	.cancel = pointer_drag_cancel,
 };
 
+uint32_t touch_drag_down(struct wlr_seat_touch_grab *grab,
+		uint32_t time, struct wlr_touch_point *point) {
+	// eat the event
+	return 0;
+}
+
+static void touch_drag_up(struct wlr_seat_touch_grab *grab, uint32_t time,
+		struct wlr_touch_point *point) {
+	struct wlr_drag *drag = grab->data;
+	if (drag->grab_touch_id != point->touch_id) {
+		return;
+	}
+
+	if (drag->focus_client && drag->focus_client->data_device) {
+		wl_data_device_send_drop(drag->focus_client->data_device);
+	}
+
+	wlr_drag_end(drag);
+}
+
+static void touch_drag_motion(struct wlr_seat_touch_grab *grab, uint32_t time,
+		struct wlr_touch_point *point) {
+	struct wlr_drag *drag = grab->data;
+	if (drag->focus && drag->focus_client && drag->focus_client->data_device) {
+		wl_data_device_send_motion(drag->focus_client->data_device, time,
+			wl_fixed_from_double(point->sx), wl_fixed_from_double(point->sy));
+	}
+}
+
+static void touch_drag_enter(struct wlr_seat_touch_grab *grab, uint32_t time,
+		struct wlr_touch_point *point) {
+	struct wlr_drag *drag = grab->data;
+	wlr_drag_set_focus(drag, point->focus_surface, point->sx, point->sy);
+}
+
+static void touch_drag_cancel(struct wlr_seat_touch_grab *grab) {
+	struct wlr_drag *drag = grab->data;
+	wlr_drag_end(drag);
+}
+
+const struct wlr_touch_grab_interface wlr_data_device_touch_drag_interface = {
+	.down = touch_drag_down,
+	.up = touch_drag_up,
+	.motion = touch_drag_motion,
+	.enter = touch_drag_enter,
+	.cancel = touch_drag_cancel,
+};
+
 static void keyboard_drag_enter(struct wlr_seat_keyboard_grab *grab,
 		struct wlr_surface *surface) {
 	// nothing has keyboard focus during drags
@@ -562,13 +615,39 @@ static void drag_handle_drag_source_destroy(struct wl_listener *listener,
 }
 
 static bool seat_client_start_drag(struct wlr_seat_client *client,
-		struct wlr_data_source *source, struct wlr_surface *icon) {
+		struct wlr_data_source *source, struct wlr_surface *icon,
+		struct wlr_surface *origin, uint32_t serial) {
 	struct wlr_drag *drag = calloc(1, sizeof(struct wlr_drag));
 	if (drag == NULL) {
 		return false;
 	}
 
-	struct wlr_seat *seat = client->seat;
+	drag->seat = client->seat;
+
+	drag->is_pointer_grab = client->pointer != NULL &&
+		client->seat->pointer_state.button_count == 1 &&
+		client->seat->pointer_state.grab_serial == serial &&
+		client->seat->pointer_state.focused_surface &&
+		client->seat->pointer_state.focused_surface == origin;
+
+	bool is_touch_grab = client->touch &&
+		wlr_seat_touch_num_points(client->seat) == 1 &&
+		client->seat->touch_state.grab_serial == serial;
+
+	// set in the iteration
+	struct wlr_touch_point *point = NULL;
+
+	if (is_touch_grab) {
+		wl_list_for_each(point, &client->seat->touch_state.touch_points, link) {
+			is_touch_grab = point->surface && point->surface == origin;
+			break;
+		}
+	}
+
+	if (!drag->is_pointer_grab && !is_touch_grab) {
+		free(drag);
+		return true;
+	}
 
 	if (icon) {
 		drag->icon = icon;
@@ -587,13 +666,23 @@ static bool seat_client_start_drag(struct wlr_seat_client *client,
 	drag->pointer_grab.data = drag;
 	drag->pointer_grab.interface = &wlr_data_device_pointer_drag_interface;
 
+	drag->touch_grab.data = drag;
+	drag->touch_grab.interface = &wlr_data_device_touch_drag_interface;
+	drag->grab_touch_id = drag->seat->touch_state.grab_id;
+
 	drag->keyboard_grab.data = drag;
 	drag->keyboard_grab.interface = &wlr_data_device_keyboard_drag_interface;
 
-	wlr_seat_pointer_clear_focus(seat);
+	wlr_seat_keyboard_start_grab(drag->seat, &drag->keyboard_grab);
 
-	wlr_seat_keyboard_start_grab(seat, &drag->keyboard_grab);
-	wlr_seat_pointer_start_grab(seat, &drag->pointer_grab);
+	if (drag->is_pointer_grab) {
+		wlr_seat_pointer_clear_focus(drag->seat);
+		wlr_seat_pointer_start_grab(drag->seat, &drag->pointer_grab);
+	} else {
+		assert(point);
+		wlr_seat_touch_start_grab(drag->seat, &drag->touch_grab);
+		wlr_drag_set_focus(drag, point->surface, point->sx, point->sy);
+	}
 
 	return true;
 }
@@ -603,21 +692,12 @@ static void data_device_start_drag(struct wl_client *client,
 		struct wl_resource *source_resource,
 		struct wl_resource *origin_resource, struct wl_resource *icon_resource,
 		uint32_t serial) {
-	struct wlr_seat_client *seat_client = wl_resource_get_user_data(device_resource);
-	struct wlr_seat *seat = seat_client->seat;
+	struct wlr_seat_client *seat_client =
+		wl_resource_get_user_data(device_resource);
 	struct wlr_surface *origin = wl_resource_get_user_data(origin_resource);
 	struct wlr_data_source *source = NULL;
 	struct wlr_surface *icon = NULL;
 
-	bool is_pointer_grab = seat->pointer_state.button_count == 1 &&
-		seat->pointer_state.grab_serial == serial &&
-		seat->pointer_state.focused_surface &&
-		seat->pointer_state.focused_surface == origin;
-
-	if (!is_pointer_grab) {
-		return;
-	}
-
 	if (source_resource) {
 		source = wl_resource_get_user_data(source_resource);
 	}
@@ -634,7 +714,7 @@ static void data_device_start_drag(struct wl_client *client,
 
 	// TODO touch grab
 
-	if (!seat_client_start_drag(seat_client, source, icon)) {
+	if (!seat_client_start_drag(seat_client, source, icon, origin, serial)) {
 		wl_resource_post_no_memory(device_resource);
 		return;
 	}
@@ -653,7 +733,8 @@ static const struct wl_data_device_interface data_device_impl = {
 void data_device_manager_get_data_device(struct wl_client *client,
 		struct wl_resource *manager_resource, uint32_t id,
 		struct wl_resource *seat_resource) {
-	struct wlr_seat_client *seat_client = wl_resource_get_user_data(seat_resource);
+	struct wlr_seat_client *seat_client =
+		wl_resource_get_user_data(seat_resource);
 
 	struct wl_resource *resource =
 		wl_resource_create(client,

types/wlr_seat.c

@@ -300,12 +300,50 @@ static const struct wlr_keyboard_grab_interface default_keyboard_grab_impl = {
 	.cancel = default_keyboard_cancel,
 };
 
+static uint32_t default_touch_down(struct wlr_seat_touch_grab *grab, uint32_t time,
+		struct wlr_touch_point *point) {
+	return wlr_seat_touch_send_down(grab->seat, point->surface, time,
+			point->touch_id, point->sx, point->sy);
+}
+
+static void default_touch_up(struct wlr_seat_touch_grab *grab, uint32_t time,
+		struct wlr_touch_point *point) {
+	wlr_seat_touch_send_up(grab->seat, time, point->touch_id);
+}
+
+static void default_touch_motion(struct wlr_seat_touch_grab *grab,
+		uint32_t time, struct wlr_touch_point *point) {
+	if (!point->focus_surface || point->focus_surface == point->surface) {
+		wlr_seat_touch_send_motion(grab->seat, time, point->touch_id, point->sx,
+			point->sy);
+	}
+}
+
+static void default_touch_enter(struct wlr_seat_touch_grab *grab,
+		uint32_t time, struct wlr_touch_point *point) {
+	// not handled by default
+}
+
+static void default_touch_cancel(struct wlr_seat_touch_grab *grab) {
+	// cannot be cancelled
+}
+
+static const struct wlr_touch_grab_interface default_touch_grab_impl = {
+	.down = default_touch_down,
+	.up = default_touch_up,
+	.motion = default_touch_motion,
+	.enter = default_touch_enter,
+	.cancel = default_touch_cancel,
+};
+
+
 struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	struct wlr_seat *wlr_seat = calloc(1, sizeof(struct wlr_seat));
 	if (!wlr_seat) {
 		return NULL;
 	}
 
+	// pointer state
 	wlr_seat->pointer_state.seat = wlr_seat;
 	wl_list_init(&wlr_seat->pointer_state.surface_destroy.link);
 	wl_list_init(&wlr_seat->pointer_state.resource_destroy.link);
@@ -321,6 +359,7 @@ struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	wlr_seat->pointer_state.default_grab = pointer_grab;
 	wlr_seat->pointer_state.grab = pointer_grab;
 
+	// keyboard state
 	struct wlr_seat_keyboard_grab *keyboard_grab =
 		calloc(1, sizeof(struct wlr_seat_keyboard_grab));
 	if (!keyboard_grab) {
@@ -338,6 +377,23 @@ struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	wl_list_init(
 		&wlr_seat->keyboard_state.surface_destroy.link);
 
+	// touch state
+	struct wlr_seat_touch_grab *touch_grab =
+		calloc(1, sizeof(struct wlr_seat_touch_grab));
+	if (!touch_grab) {
+		free(pointer_grab);
+		free(keyboard_grab);
+		free(wlr_seat);
+		return NULL;
+	}
+	touch_grab->interface = &default_touch_grab_impl;
+	touch_grab->seat = wlr_seat;
+	wlr_seat->touch_state.default_grab = touch_grab;
+	wlr_seat->touch_state.grab = touch_grab;
+
+	wlr_seat->touch_state.seat = wlr_seat;
+	wl_list_init(&wlr_seat->touch_state.touch_points);
+
 	struct wl_global *wl_global = wl_global_create(display,
 		&wl_seat_interface, 6, wlr_seat, wl_seat_bind);
 	if (!wl_global) {
@@ -361,6 +417,9 @@ struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	wl_signal_init(&wlr_seat->events.keyboard_grab_begin);
 	wl_signal_init(&wlr_seat->events.keyboard_grab_end);
 
+	wl_signal_init(&wlr_seat->events.touch_grab_begin);
+	wl_signal_init(&wlr_seat->events.touch_grab_end);
+
 	return wlr_seat;
 }
 
@@ -378,6 +437,7 @@ void wlr_seat_destroy(struct wlr_seat *wlr_seat) {
 	wl_global_destroy(wlr_seat->wl_global);
 	free(wlr_seat->pointer_state.default_grab);
 	free(wlr_seat->keyboard_state.default_grab);
+	free(wlr_seat->touch_state.default_grab);
 	free(wlr_seat->data_device);
 	free(wlr_seat->name);
 	free(wlr_seat);
@@ -550,7 +610,9 @@ void wlr_seat_pointer_send_axis(struct wlr_seat *wlr_seat, uint32_t time,
 
 void wlr_seat_pointer_start_grab(struct wlr_seat *wlr_seat,
 		struct wlr_seat_pointer_grab *grab) {
+	assert(wlr_seat);
 	grab->seat = wlr_seat;
+	assert(grab->seat);
 	wlr_seat->pointer_state.grab = grab;
 
 	wl_signal_emit(&wlr_seat->events.pointer_grab_begin, grab);
@@ -596,7 +658,7 @@ uint32_t wlr_seat_pointer_notify_button(struct wlr_seat *wlr_seat,
 	struct wlr_seat_pointer_grab *grab = wlr_seat->pointer_state.grab;
 	uint32_t serial = grab->interface->button(grab, time, button, state);
 
-	if (wlr_seat->pointer_state.button_count == 1) {
+	if (serial && wlr_seat->pointer_state.button_count == 1) {
 		wlr_seat->pointer_state.grab_serial = serial;
 	}
 
@@ -610,6 +672,10 @@ void wlr_seat_pointer_notify_axis(struct wlr_seat *wlr_seat, uint32_t time,
 	grab->interface->axis(grab, time, orientation, value);
 }
 
+bool wlr_seat_pointer_has_grab(struct wlr_seat *seat) {
+	return seat->pointer_state.grab->interface != &default_pointer_grab_impl;
+}
+
 void wlr_seat_keyboard_send_key(struct wlr_seat *wlr_seat, uint32_t time,
 		uint32_t key, uint32_t state) {
 	struct wlr_seat_client *client = wlr_seat->keyboard_state.focused_client;
@@ -807,6 +873,10 @@ void wlr_seat_keyboard_clear_focus(struct wlr_seat *seat) {
 	wlr_seat_keyboard_enter(seat, NULL);
 }
 
+bool wlr_seat_keyboard_has_grab(struct wlr_seat *seat) {
+	return seat->keyboard_state.grab->interface != &default_keyboard_grab_impl;
+}
+
 void wlr_seat_keyboard_notify_modifiers(struct wlr_seat *seat) {
 	clock_gettime(CLOCK_MONOTONIC, &seat->last_event);
 	struct wlr_seat_keyboard_grab *grab = seat->keyboard_state.grab;
@@ -819,3 +889,265 @@ void wlr_seat_keyboard_notify_key(struct wlr_seat *seat, uint32_t time,
 	struct wlr_seat_keyboard_grab *grab = seat->keyboard_state.grab;
 	grab->interface->key(grab, time, key, state);
 }
+
+void wlr_seat_touch_start_grab(struct wlr_seat *wlr_seat,
+		struct wlr_seat_touch_grab *grab) {
+	grab->seat = wlr_seat;
+	wlr_seat->touch_state.grab = grab;
+
+	wl_signal_emit(&wlr_seat->events.touch_grab_begin, grab);
+}
+
+void wlr_seat_touch_end_grab(struct wlr_seat *wlr_seat) {
+	struct wlr_seat_touch_grab *grab = wlr_seat->touch_state.grab;
+
+	if (grab != wlr_seat->touch_state.default_grab) {
+		wlr_seat->touch_state.grab = wlr_seat->touch_state.default_grab;
+		wl_signal_emit(&wlr_seat->events.touch_grab_end, grab);
+		if (grab->interface->cancel) {
+			grab->interface->cancel(grab);
+		}
+	}
+}
+
+static void touch_point_clear_focus(struct wlr_touch_point *point) {
+	if (point->focus_surface) {
+		wl_list_remove(&point->focus_surface_destroy.link);
+		point->focus_client = NULL;
+		point->focus_surface = NULL;
+	}
+}
+
+static void touch_point_destroy(struct wlr_touch_point *point) {
+	wl_signal_emit(&point->events.destroy, point);
+
+	touch_point_clear_focus(point);
+	wl_list_remove(&point->surface_destroy.link);
+	wl_list_remove(&point->resource_destroy.link);
+	wl_list_remove(&point->link);
+	free(point);
+}
+static void handle_touch_point_resource_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_touch_point *point =
+		wl_container_of(listener, point, resource_destroy);
+	touch_point_destroy(point);
+}
+
+static void handle_touch_point_surface_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_touch_point *point =
+		wl_container_of(listener, point, surface_destroy);
+	touch_point_destroy(point);
+}
+
+static struct wlr_touch_point *touch_point_create(
+		struct wlr_seat *seat, int32_t touch_id,
+		struct wlr_surface *surface, double sx, double sy) {
+	struct wl_client *wl_client = wl_resource_get_client(surface->resource);
+	struct wlr_seat_client *client = wlr_seat_client_for_wl_client(seat, wl_client);
+
+	if (!client || !client->touch) {
+		// touch points are not valid without a connected client with touch
+		return NULL;
+	}
+
+	struct wlr_touch_point *point = calloc(1, sizeof(struct wlr_touch_point));
+	if (!point) {
+		return NULL;
+	}
+
+	point->touch_id = touch_id;
+	point->surface = surface;
+	point->client = client;
+
+	point->sx = sx;
+	point->sy = sy;
+
+	wl_signal_init(&point->events.destroy);
+
+	wl_signal_add(&surface->events.destroy, &point->surface_destroy);
+	point->surface_destroy.notify = handle_touch_point_surface_destroy;
+	wl_resource_add_destroy_listener(surface->resource,
+		&point->resource_destroy);
+	point->resource_destroy.notify = handle_touch_point_resource_destroy;
+
+	wl_list_insert(&seat->touch_state.touch_points, &point->link);
+
+	return point;
+}
+
+struct wlr_touch_point *wlr_seat_touch_get_point(
+		struct wlr_seat *seat, int32_t touch_id) {
+	struct wlr_touch_point *point = NULL;
+	wl_list_for_each(point, &seat->touch_state.touch_points, link) {
+		if (point->touch_id == touch_id) {
+			return point;
+		}
+	}
+
+	return NULL;
+}
+
+uint32_t wlr_seat_touch_notify_down(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy) {
+	clock_gettime(CLOCK_MONOTONIC, &seat->last_event);
+	struct wlr_seat_touch_grab *grab = seat->touch_state.grab;
+	struct wlr_touch_point *point =
+		touch_point_create(seat, touch_id, surface, sx, sy);
+	if (!point) {
+		wlr_log(L_ERROR, "could not create touch point");
+		return 0;
+	}
+
+	uint32_t serial = grab->interface->down(grab, time, point);
+
+	if (serial && wlr_seat_touch_num_points(seat) == 1) {
+		seat->touch_state.grab_serial = serial;
+		seat->touch_state.grab_id = touch_id;
+	}
+
+	return serial;
+}
+
+void wlr_seat_touch_notify_up(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id) {
+	clock_gettime(CLOCK_MONOTONIC, &seat->last_event);
+	struct wlr_seat_touch_grab *grab = seat->touch_state.grab;
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch up for unknown touch point");
+		return;
+	}
+
+	grab->interface->up(grab, time, point);
+
+	touch_point_destroy(point);
+}
+
+void wlr_seat_touch_notify_motion(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id, double sx, double sy) {
+	clock_gettime(CLOCK_MONOTONIC, &seat->last_event);
+	struct wlr_seat_touch_grab *grab = seat->touch_state.grab;
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch motion for unknown touch point");
+		return;
+	}
+
+	point->sx = sx;
+	point->sy = sy;
+
+	grab->interface->motion(grab, time, point);
+}
+
+static void handle_point_focus_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_touch_point *point =
+		wl_container_of(listener, point, focus_surface_destroy);
+	touch_point_clear_focus(point);
+}
+
+static void touch_point_set_focus(struct wlr_touch_point *point,
+		struct wlr_surface *surface, double sx, double sy) {
+	if (point->focus_surface == surface) {
+		return;
+	}
+
+	touch_point_clear_focus(point);
+
+	if (surface && surface->resource) {
+		struct wlr_seat_client *client =
+			wlr_seat_client_for_wl_client(point->client->seat,
+				wl_resource_get_client(surface->resource));
+
+		if (client && client->touch) {
+			wl_signal_add(&surface->events.destroy, &point->focus_surface_destroy);
+			point->focus_surface_destroy.notify = handle_point_focus_destroy;
+			point->focus_surface = surface;
+			point->focus_client = client;
+			point->sx = sx;
+			point->sy = sy;
+		}
+	}
+}
+
+void wlr_seat_touch_point_focus(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy) {
+	assert(surface);
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch point focus for unknown touch point");
+		return;
+	}
+	struct wlr_surface *focus = point->focus_surface;
+	touch_point_set_focus(point, surface, sx, sy);
+
+	if (focus != point->focus_surface) {
+		struct wlr_seat_touch_grab *grab = seat->touch_state.grab;
+		grab->interface->enter(grab, time, point);
+	}
+}
+
+void wlr_seat_touch_point_clear_focus(struct wlr_seat *seat, uint32_t time,
+		int32_t touch_id) {
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch point focus for unknown touch point");
+		return;
+	}
+
+	touch_point_clear_focus(point);
+}
+
+uint32_t wlr_seat_touch_send_down(struct wlr_seat *seat,
+		struct wlr_surface *surface, uint32_t time, int32_t touch_id, double sx,
+		double sy) {
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch down for unknown touch point");
+		return 0;
+	}
+
+	uint32_t serial = wl_display_next_serial(seat->display);
+	wl_touch_send_down(point->client->touch, serial, time, surface->resource,
+		touch_id, wl_fixed_from_double(sx), wl_fixed_from_double(sy));
+	wl_touch_send_frame(point->client->touch);
+
+	return serial;
+}
+
+void wlr_seat_touch_send_up(struct wlr_seat *seat, uint32_t time, int32_t touch_id) {
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch up for unknown touch point");
+		return;
+	}
+
+	uint32_t serial = wl_display_next_serial(seat->display);
+	wl_touch_send_up(point->client->touch, serial, time, touch_id);
+	wl_touch_send_frame(point->client->touch);
+}
+
+void wlr_seat_touch_send_motion(struct wlr_seat *seat, uint32_t time, int32_t touch_id,
+		double sx, double sy) {
+	struct wlr_touch_point *point = wlr_seat_touch_get_point(seat, touch_id);
+	if (!point) {
+		wlr_log(L_ERROR, "got touch motion for unknown touch point");
+		return;
+	}
+
+	wl_touch_send_motion(point->client->touch, time, touch_id,
+		wl_fixed_from_double(sx), wl_fixed_from_double(sy));
+	wl_touch_send_frame(point->client->touch);
+}
+
+int wlr_seat_touch_num_points(struct wlr_seat *seat) {
+	return wl_list_length(&seat->touch_state.touch_points);
+}
+
+bool wlr_seat_touch_has_grab(struct wlr_seat *seat) {
+	return seat->touch_state.grab->interface != &default_touch_grab_impl;
+}