libweston: handle tablet cursors in the compositor

The tablet is given a separate cursor. Most tablet interaction is an absolute
interaction and shouldn't need a cursor at all, but usually the cursor is used
to indicate the type of virtual tool currently assigned.

Based on patches from
Peter Hutterer <peter.hutterer@who-t.net>
Lyude Paul <thatslyude@gmail.com>
Bastian Farkas <bfarkas@de.adit-jv.com>
Maniraj Devadoss <Maniraj.Devadoss@in.bosch.com>

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>

3 files changed, 144 insertions, 0 deletions

diff --git a/include/libweston/libweston.h b/include/libweston/libweston.h
index b18d0639..207cf771 100644
--- a/include/libweston/libweston.h
+++ b/include/libweston/libweston.h
@@ -908,6 +908,12 @@ struct weston_tablet_tool {
 	bool tip_is_down;
 
 	struct timespec frame_time;
+
+	struct weston_view *sprite;
+	struct weston_coord_surface hotspot;
+	struct wl_listener sprite_destroy_listener;
+
+	struct weston_coord_global pos;
 };
 
 struct weston_tablet {
@@ -1064,6 +1070,10 @@ void
 weston_tablet_tool_send_frame(struct weston_tablet_tool *tool,
 			       const struct timespec *time);
 
+void
+weston_tablet_tool_cursor_move(struct weston_tablet_tool *tool,
+			       struct weston_coord_global pos);
+
 
 void
 weston_seat_set_selection(struct weston_seat *seat,
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 82363d29..ef6d7872 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -2063,6 +2063,7 @@ weston_view_unmap(struct weston_view *view)
 			struct weston_pointer *pointer = weston_seat_get_pointer(seat);
 			struct weston_keyboard *keyboard =
 				weston_seat_get_keyboard(seat);
+			struct weston_tablet_tool *tool;
 
 			if (keyboard && keyboard->focus == view->surface)
 				weston_keyboard_set_focus(keyboard, NULL);
@@ -2070,6 +2071,11 @@ weston_view_unmap(struct weston_view *view)
 				weston_pointer_clear_focus(pointer);
 			if (touch && touch->focus == view)
 				weston_touch_set_focus(touch, NULL);
+
+			wl_list_for_each(tool, &seat->tablet_tool_list, link) {
+				if (tool->focus == view)
+					weston_tablet_tool_set_focus(tool, NULL, 0);
+			}
 		}
 	}
 	weston_signal_emit_mutable(&view->unmap_signal, view);
diff --git a/libweston/input.c b/libweston/input.c
index 4301a288..4f3c7ec1 100644
--- a/libweston/input.c
+++ b/libweston/input.c
@@ -1563,6 +1563,10 @@ weston_tablet_tool_send_proximity_out(struct weston_tablet_tool *tool,
 				      const struct timespec *time)
 {
 	weston_tablet_tool_set_focus(tool, NULL, time);
+
+	/* Hide the cursor */
+	if (tool->sprite && weston_surface_is_mapped(tool->sprite->surface))
+		weston_surface_unmap(tool->sprite->surface);
 }
 
 static void
@@ -1584,6 +1588,7 @@ weston_tablet_tool_send_motion(struct weston_tablet_tool *tool,
 	current_view = weston_compositor_pick_view(tool->seat->compositor, pos);
 	if (current_view != tool->focus)
 		weston_tablet_tool_set_focus(tool, current_view, time);
+	weston_tablet_tool_cursor_move(tool, pos);
 	surf_pos = weston_coord_global_to_surface(tool->focus, pos);
 
 	wl_resource_for_each(resource, &tool->focus_resource_list) {
@@ -1770,6 +1775,29 @@ static struct weston_tablet_tool_grab_interface default_tablet_tool_grab_interfa
 	default_grab_tablet_tool_cancel,
 };
 
+static void
+tablet_tool_unmap_sprite(struct weston_tablet_tool *tool)
+{
+	if (weston_surface_is_mapped(tool->sprite->surface))
+		weston_surface_unmap(tool->sprite->surface);
+
+	wl_list_remove(&tool->sprite_destroy_listener.link);
+	tool->sprite->surface->committed = NULL;
+	tool->sprite->surface->committed_private = NULL;
+	weston_view_destroy(tool->sprite);
+	tool->sprite = NULL;
+}
+
+static void
+tablet_tool_handle_sprite_destroy(struct wl_listener *listener, void *data)
+{
+	struct weston_tablet_tool *tool =
+		container_of(listener, struct weston_tablet_tool,
+			     sprite_destroy_listener);
+
+	tool->sprite = NULL;
+}
+
 WL_EXPORT struct weston_tablet_tool *
 weston_tablet_tool_create(void)
 {
@@ -1782,6 +1810,9 @@ weston_tablet_tool_create(void)
 	wl_list_init(&tool->resource_list);
 	wl_list_init(&tool->focus_resource_list);
 
+	wl_list_init(&tool->sprite_destroy_listener.link);
+	tool->sprite_destroy_listener.notify = tablet_tool_handle_sprite_destroy;
+
 	wl_list_init(&tool->focus_view_listener.link);
 	tool->focus_view_listener.notify = tablet_tool_focus_view_destroyed;
 
@@ -1800,6 +1831,9 @@ weston_tablet_tool_destroy(struct weston_tablet_tool *tool)
 {
 	struct wl_resource *resource, *tmp;
 
+	if (tool->sprite)
+		tablet_tool_unmap_sprite(tool);
+
 	wl_resource_for_each_safe(resource, tmp, &tool->resource_list) {
 		zwp_tablet_tool_v2_send_removed(resource);
 		wl_resource_set_user_data(resource, NULL);
@@ -1816,6 +1850,19 @@ weston_tablet_tool_destroy(struct weston_tablet_tool *tool)
 	free(tool);
 }
 
+WL_EXPORT void
+weston_tablet_tool_cursor_move(struct weston_tablet_tool *tool,
+			       struct weston_coord_global pos)
+{
+	tool->pos = pos;
+
+	if (tool->sprite) {
+		weston_view_set_position(tool->sprite,
+					 pos.c.x - tool->hotspot.c.x,
+					 pos.c.y - tool->hotspot.c.y);
+		weston_view_schedule_repaint(tool->sprite);
+	}
+}
 
 static void
 seat_send_updated_caps(struct weston_seat *seat)
@@ -3164,10 +3211,91 @@ notify_tablet_added(struct weston_tablet *tablet)
 }
 
 static void
+tablet_tool_cursor_surface_committed(struct weston_surface *es,
+				     struct weston_coord_surface new_origin)
+{
+	struct weston_tablet_tool *tool = es->committed_private;
+	struct weston_coord_global pos;
+
+	if (es->width == 0)
+		return;
+
+	assert(es == tool->sprite->surface);
+
+	tool->hotspot.c = weston_coord_sub(tool->hotspot.c, new_origin.c);
+	pos.c = weston_coord_sub(tool->pos.c, tool->hotspot.c);
+
+	weston_view_set_position(tool->sprite, pos.c.x, pos.c.y);
+
+	empty_region(&es->pending.input);
+	empty_region(&es->input);
+
+	if (!weston_surface_is_mapped(es)) {
+		weston_layer_entry_insert(
+			&es->compositor->cursor_layer.view_list,
+			&tool->sprite->layer_link);
+		weston_view_update_transform(tool->sprite);
+		es->is_mapped = true;
+		tool->sprite->is_mapped = true;
+	}
+}
+
+static void
 tablet_tool_set_cursor(struct wl_client *client, struct wl_resource *resource,
 		       uint32_t serial, struct wl_resource *surface_resource,
 		       int32_t hotspot_x, int32_t hotspot_y)
 {
+	struct weston_tablet_tool *tool = wl_resource_get_user_data(resource);
+	struct weston_surface *surface = NULL;
+
+	if (!tool)
+		return;
+
+	if (surface_resource)
+		surface = wl_resource_get_user_data(surface_resource);
+
+	if (tool->focus == NULL)
+		return;
+
+	/* tablet->focus->surface->resource can be NULL. Surfaces like the
+	 * black_surface used in shell.c for fullscreen don't have
+	 * a resource, but can still have focus */
+	if (tool->focus->surface->resource == NULL)
+		return;
+
+	if (wl_resource_get_client(tool->focus->surface->resource) != client)
+		return;
+
+	if (tool->focus_serial - serial > UINT32_MAX / 2)
+		return;
+
+	if (surface && tool->sprite && surface != tool->sprite->surface &&
+	    surface->committed) {
+		wl_resource_post_error(surface->resource,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "surface->configure already set");
+		return;
+	}
+
+	if (tool->sprite)
+		tablet_tool_unmap_sprite(tool);
+
+	if (!surface)
+		return;
+
+	wl_signal_add(&surface->destroy_signal,
+		      &tool->sprite_destroy_listener);
+	surface->committed = tablet_tool_cursor_surface_committed;
+	surface->committed_private = tool;
+	tool->sprite = weston_view_create(surface);
+	tool->hotspot = weston_coord_surface(hotspot_x, hotspot_y, surface);
+
+	if (surface->buffer_ref.buffer) {
+		struct weston_coord_surface delta =
+			weston_coord_surface(0, 0, surface);
+
+		tablet_tool_cursor_surface_committed(surface, delta);
+	}
 }
 
 static void