Animate transitions for zoom focus point change.

Handle the transition when focus changes from text cursor to
mouse pointer or vice versa.
diff --git a/src/compositor.c b/src/compositor.c
index 55b0efc..e550926 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -1633,7 +1633,7 @@
 		if (output->zoom.active &&
 		    pixman_region32_contains_point(&output->region,
 						   ix, iy, NULL))
-			weston_output_update_zoom(output, x, y, ZOOM_FOCUS_POINTER);
+			weston_output_update_zoom(output, ZOOM_FOCUS_POINTER);
 
 	weston_device_repick(seat);
 	interface = seat->pointer->grab->interface;
@@ -2783,9 +2783,11 @@
 		    pixman_region32_contains_point(&output->region,
 						wl_fixed_to_int(global_x),
 						wl_fixed_to_int(global_y),
-						NULL))
-			weston_output_update_zoom(output, global_x, global_y,
-							  ZOOM_FOCUS_TEXT);
+						NULL)) {
+			output->zoom.text_cursor.x = global_x;
+			output->zoom.text_cursor.y = global_y;
+			weston_output_update_zoom(output, ZOOM_FOCUS_TEXT);
+		}
 }
 
 static void
@@ -2815,8 +2817,133 @@
 }
 
 static void
-weston_zoom_transition(struct weston_output *output)
+weston_zoom_frame_xy(struct weston_animation *animation,
+		struct weston_output *output, uint32_t msecs)
 {
+	wl_fixed_t x, y;
+	if (animation->frame_counter <= 1)
+		output->zoom.spring_xy.timestamp = msecs;
+
+	weston_spring_update(&output->zoom.spring_xy, msecs);
+
+	x = output->zoom.from.x - ((output->zoom.from.x - output->zoom.to.x) *
+						output->zoom.spring_xy.current);
+	y = output->zoom.from.y - ((output->zoom.from.y - output->zoom.to.y) *
+						output->zoom.spring_xy.current);
+
+	output->zoom.current.x = x;
+	output->zoom.current.y = y;
+
+	if (weston_spring_done(&output->zoom.spring_xy)) {
+		output->zoom.spring_xy.current = output->zoom.spring_xy.target;
+		output->zoom.current.x =
+				(output->zoom.type == ZOOM_FOCUS_POINTER) ?
+					output->compositor->seat->pointer.x :
+					output->zoom.text_cursor.x;
+		output->zoom.current.y =
+				(output->zoom.type == ZOOM_FOCUS_POINTER) ?
+					output->compositor->seat->pointer.y :
+					output->zoom.text_cursor.y;
+		wl_list_remove(&animation->link);
+		wl_list_init(&animation->link);
+	}
+
+	output->dirty = 1;
+	weston_output_damage(output);
+}
+
+static void
+zoom_area_center_from_pointer(struct weston_output *output,
+				wl_fixed_t *x, wl_fixed_t *y)
+{
+	float level = output->zoom.spring_z.current;
+	wl_fixed_t offset_x = wl_fixed_from_int(output->x);
+	wl_fixed_t offset_y = wl_fixed_from_int(output->y);
+	wl_fixed_t w = wl_fixed_from_int(output->current->width);
+	wl_fixed_t h = wl_fixed_from_int(output->current->height);
+
+	*x -= ((((*x - offset_x) / (float) w) - 0.5) * (w * (1.0 - level)));
+	*y -= ((((*y - offset_y) / (float) h) - 0.5) * (h * (1.0 - level)));
+}
+
+static void
+weston_output_update_zoom_transform(struct weston_output *output)
+{
+	uint32_t type = output->zoom.type;
+	float global_x, global_y;
+	wl_fixed_t x = output->zoom.current.x;
+	wl_fixed_t y = output->zoom.current.y;
+	float trans_min, trans_max;
+	float ratio, level;
+
+	level = output->zoom.spring_z.current;
+	ratio = 1 / level;
+
+	if (!output->zoom.active || level > output->zoom.max_level)
+		return;
+
+	if (type == ZOOM_FOCUS_POINTER &&
+			wl_list_empty(&output->zoom.animation_xy.link))
+		zoom_area_center_from_pointer(output, &x, &y);
+
+	global_x = wl_fixed_to_double(x);
+	global_y = wl_fixed_to_double(y);
+
+	output->zoom.trans_x =
+		((((global_x - output->x) / output->current->width) *
+		(level * 2)) - level) * ratio;
+	output->zoom.trans_y =
+		((((global_y - output->y) / output->current->height) *
+		(level * 2)) - level) * ratio;
+
+	trans_max = level * 2 - level;
+	trans_min = -trans_max;
+
+	/* Clip zoom area to output */
+	if (output->zoom.trans_x > trans_max)
+		output->zoom.trans_x = trans_max;
+	else if (output->zoom.trans_x < trans_min)
+		output->zoom.trans_x = trans_min;
+	if (output->zoom.trans_y > trans_max)
+		output->zoom.trans_y = trans_max;
+	else if (output->zoom.trans_y < trans_min)
+		output->zoom.trans_y = trans_min;
+}
+
+static void
+weston_zoom_transition(struct weston_output *output, uint32_t type,
+						wl_fixed_t x, wl_fixed_t y)
+{
+	if (output->zoom.type != type) {
+		/* Set from/to points and start animation */
+		output->zoom.spring_xy.current = 0.0;
+		output->zoom.spring_xy.previous = 0.0;
+		output->zoom.spring_xy.target = 1.0;
+
+		if (wl_list_empty(&output->zoom.animation_xy.link)) {
+			output->zoom.animation_xy.frame_counter = 0;
+			wl_list_insert(output->animation_list.prev,
+				&output->zoom.animation_xy.link);
+
+			output->zoom.from.x = (type == ZOOM_FOCUS_TEXT) ?
+						x : output->zoom.text_cursor.x;
+			output->zoom.from.y = (type == ZOOM_FOCUS_TEXT) ?
+						y : output->zoom.text_cursor.y;
+		} else {
+			output->zoom.from.x = output->zoom.current.x;
+			output->zoom.from.y = output->zoom.current.y;
+		}
+
+		output->zoom.to.x = (type == ZOOM_FOCUS_POINTER) ?
+						x : output->zoom.text_cursor.x;
+		output->zoom.to.y = (type == ZOOM_FOCUS_POINTER) ?
+						y : output->zoom.text_cursor.y;
+		output->zoom.current.x = output->zoom.from.x;
+		output->zoom.current.y = output->zoom.from.y;
+
+		output->zoom.type = type;
+	}
+
 	if (output->zoom.level != output->zoom.spring_z.current) {
 		output->zoom.spring_z.target = output->zoom.level;
 		if (wl_list_empty(&output->zoom.animation_z.link)) {
@@ -2831,55 +2958,37 @@
 }
 
 WL_EXPORT void
-weston_output_update_zoom(struct weston_output *output,
-						wl_fixed_t x,
-						wl_fixed_t y,
-						uint32_t type)
+weston_output_update_zoom(struct weston_output *output, uint32_t type)
 {
-	float global_x, global_y;
-	float trans_min, trans_max;
-	float ratio, level;
+	wl_fixed_t x = output->compositor->seat->pointer.x;
+	wl_fixed_t y = output->compositor->seat->pointer.y;
 
-	level = output->zoom.spring_z.current;
+	zoom_area_center_from_pointer(output, &x, &y);
 
-	if (!output->zoom.active || level > output->zoom.max_level)
-		return;
-
-	output->zoom.type = type;
-
-	output->zoom.fx = x;
-	output->zoom.fy = y;
-
-	global_x = wl_fixed_to_double(x);
-	global_y = wl_fixed_to_double(y);
-
-	output->zoom.trans_x =
-		(((global_x - output->x) / output->current->width) *
-		(level * 2)) - level;
-	output->zoom.trans_y =
-		(((global_y - output->y) / output->current->height) *
-		(level * 2)) - level;
-
-	if (type == ZOOM_FOCUS_TEXT) {
-		ratio = 1 / level;
-
-		output->zoom.trans_x *= ratio;
-		output->zoom.trans_y *= ratio;
-
-		trans_max = level * 2 - level;
-		trans_min = -trans_max;
-
-		if (output->zoom.trans_x > trans_max)
-			output->zoom.trans_x = trans_max;
-		else if (output->zoom.trans_x < trans_min)
-			output->zoom.trans_x = trans_min;
-		if (output->zoom.trans_y > trans_max)
-			output->zoom.trans_y = trans_max;
-		else if (output->zoom.trans_y < trans_min)
-			output->zoom.trans_y = trans_min;
+	if (type == ZOOM_FOCUS_POINTER) {
+		if (wl_list_empty(&output->zoom.animation_xy.link)) {
+			output->zoom.current.x =
+					output->compositor->seat->pointer.x;
+			output->zoom.current.y =
+					output->compositor->seat->pointer.y;
+		} else {
+			output->zoom.to.x = x;
+			output->zoom.to.y = y;
+		}
 	}
 
-	weston_zoom_transition(output);
+	if (type == ZOOM_FOCUS_TEXT) {
+		if (wl_list_empty(&output->zoom.animation_xy.link)) {
+			output->zoom.current.x = output->zoom.text_cursor.x;
+			output->zoom.current.y = output->zoom.text_cursor.y;
+		} else {
+			output->zoom.to.x = output->zoom.text_cursor.x;
+			output->zoom.to.y = output->zoom.text_cursor.y;
+		}
+	}
+
+	weston_zoom_transition(output, type, x, y);
+	weston_output_update_zoom_transform(output);
 }
 
 WL_EXPORT void
@@ -2904,9 +3013,7 @@
 		magnification = 1 / (1 - output->zoom.spring_z.current);
 		weston_matrix_init(&camera);
 		weston_matrix_init(&modelview);
-		weston_output_update_zoom(output, output->zoom.fx,
-						  output->zoom.fy,
-						  output->zoom.type);
+		weston_output_update_zoom(output, output->zoom.type);
 		weston_matrix_translate(&camera, output->zoom.trans_x,
 					  flip * output->zoom.trans_y, 0);
 		weston_matrix_invert(&modelview, &camera);
@@ -2951,10 +3058,15 @@
 	output->zoom.level = 0.0;
 	output->zoom.trans_x = 0.0;
 	output->zoom.trans_y = 0.0;
+	output->zoom.type = ZOOM_FOCUS_POINTER;
 	weston_spring_init(&output->zoom.spring_z, 250.0, 0.0, 0.0);
 	output->zoom.spring_z.friction = 1000;
 	output->zoom.animation_z.frame = weston_zoom_frame_z;
 	wl_list_init(&output->zoom.animation_z.link);
+	weston_spring_init(&output->zoom.spring_xy, 250.0, 0.0, 0.0);
+	output->zoom.spring_xy.friction = 1000;
+	output->zoom.animation_xy.frame = weston_zoom_frame_xy;
+	wl_list_init(&output->zoom.animation_xy.link);
 
 	output->flags = flags;
 	weston_output_move(output, x, y);