window: Implement animated cursors (using pointer surfaces)

Since the introduction of pointer.set_cursor(), it is possible for a
client to set the surface containing the pointer image and get frame
callbacks on it thus allowing a clear implementation of animated
cursors.

This also makes the busy cursor hack of using frame callbacks on the
busy surface unnecessary.

clients/desktop-shell.c

@@ -767,42 +767,10 @@ background_create(struct desktop *desktop)
 	return background;
 }
 
-static const struct wl_callback_listener busy_cursor_listener;
-
-static void
-busy_cursor_frame_callback(void *data,
-			   struct wl_callback *callback, uint32_t time)
-{
-	struct input *input = data;
-	struct display *display = input_get_display(input);
-	struct desktop *desktop = display_get_user_data(display);
-	struct wl_surface *surface;
-	int index;
-
-	if (callback)
-		wl_callback_destroy(callback);
-	if (input_get_focus_widget(input) != desktop->busy_widget)
-		return;
-
-	/* FIXME: Get frame duration and number of frames from cursor. */
-	index = (time / 100) % 8;
-	input_set_pointer_image_index(input, CURSOR_WATCH, index);
-
-	surface = window_get_wl_surface(desktop->busy_window);
-	callback = wl_surface_frame(surface);
-	wl_callback_add_listener(callback, &busy_cursor_listener, input);
-}
-
-static const struct wl_callback_listener busy_cursor_listener = {
-	busy_cursor_frame_callback
-};
-
 static int
 busy_surface_enter_handler(struct widget *widget, struct input *input,
 			   float x, float y, void *data)
 {
-	busy_cursor_frame_callback(input, NULL, 0);
-
 	return CURSOR_WATCH;
 }
 

clients/window.c

@@ -189,6 +189,8 @@ struct input {
 	struct window *pointer_focus;
 	struct window *keyboard_focus;
 	int current_cursor;
+	uint32_t cursor_anim_start;
+	struct wl_callback *cursor_frame_cb;
 	struct wl_surface *pointer_surface;
 	uint32_t modifiers;
 	uint32_t pointer_enter_serial;
@@ -2274,14 +2276,14 @@ static const struct wl_data_device_listener data_device_listener = {
 	data_device_selection
 };
 
-void
-input_set_pointer_image_index(struct input *input, int pointer, int index)
+static void
+input_set_pointer_image_index(struct input *input, int index)
 {
 	struct wl_buffer *buffer;
 	struct wl_cursor *cursor;
 	struct wl_cursor_image *image;
 
-	cursor = input->display->cursors[pointer];
+	cursor = input->display->cursors[input->current_cursor];
 	if (!cursor)
 		return;
 
@@ -2295,7 +2297,6 @@ input_set_pointer_image_index(struct input *input, int pointer, int index)
 	if (!buffer)
 		return;
 
-	input->current_cursor = pointer;
 	wl_pointer_set_cursor(input->pointer, input->display->serial,
 			      input->pointer_surface,
 			      image->hotspot_x, image->hotspot_y);
@@ -2304,13 +2305,61 @@ input_set_pointer_image_index(struct input *input, int pointer, int index)
 			  image->width, image->height);
 }
 
+static const struct wl_callback_listener pointer_surface_listener;
+
+static void
+pointer_surface_frame_callback(void *data, struct wl_callback *callback,
+			       uint32_t time)
+{
+	struct input *input = data;
+	struct wl_cursor *cursor =
+		input->display->cursors[input->current_cursor];
+	int i;
+
+	if (callback) {
+		assert(callback == input->cursor_frame_cb);
+		wl_callback_destroy(callback);
+		input->cursor_frame_cb = NULL;
+	}
+
+	if (input->current_cursor == CURSOR_UNSET)
+		return;
+
+	/* FIXME We don't have the current time on the first call so we set
+	 * the animation start to the time of the first frame callback. */
+	if (time == 0)
+		input->cursor_anim_start = 0;
+	else if (input->cursor_anim_start == 0)
+		input->cursor_anim_start = time;
+
+	if (time == 0 || input->cursor_anim_start == 0)
+		i = 0;
+	else
+		i = wl_cursor_frame(cursor, time - input->cursor_anim_start);
+
+	input_set_pointer_image_index(input, i);
+
+	if (cursor->image_count == 1)
+		return;
+
+	input->cursor_frame_cb = wl_surface_frame(input->pointer_surface);
+	wl_callback_add_listener(input->cursor_frame_cb,
+				 &pointer_surface_listener, input);
+}
+
+static const struct wl_callback_listener pointer_surface_listener = {
+	pointer_surface_frame_callback
+};
+
 void
 input_set_pointer_image(struct input *input, int pointer)
 {
 	if (pointer == input->current_cursor)
 		return;
 
-	input_set_pointer_image_index(input, pointer, 0);
+	input->current_cursor = pointer;
+	if (!input->cursor_frame_cb)
+		pointer_surface_frame_callback(input, NULL, 0);
 }
 
 struct wl_data_device *

clients/window.h

@@ -367,9 +367,6 @@ frame_create(struct window *window, void *data);
 void
 input_set_pointer_image(struct input *input, int pointer);
 
-void
-input_set_pointer_image_index(struct input *input, int pointer, int index);
-
 void
 input_get_position(struct input *input, int32_t *x, int32_t *y);