wobbly: Fix resizing for wobbly surfaces

This problem was due to the fact that rotate changed the
surface position when rotating to offset the fact that
resize didn't keep the position updated as expected, that
is, position.p + 0.5 * size.p = center.p. Wobbly must also
make this assumption to sync correctly but the position
must be adjusted during resize, not on rotate motion.

As a side note, shell_surface_adjust_for_transform should
end up in the rotate plugin resize handler, if/when it is
ported to a standalone version.

Author: soreau

desktop-shell/shell.c

@@ -4343,7 +4343,7 @@ rotate_grab_motion(struct weston_pointer_grab *grab, uint32_t time,
 		container_of(grab, struct rotate_grab, base.grab);
 	struct weston_pointer *pointer = grab->pointer;
 	struct shell_surface *shsurf = rotate->base.shsurf;
-	float cx, cy, dx, dy, cposx, cposy, dposx, dposy, r;
+	float cx, cy, dx, dy, r;
 
 	weston_pointer_move(pointer, x, y);
 
@@ -4382,18 +4382,6 @@ rotate_grab_motion(struct weston_pointer_grab *grab, uint32_t time,
 		weston_matrix_init(&rotate->rotation);
 	}
 
-	/* We need to adjust the position of the surface
-	 * in case it was resized in a rotated state before */
-	cposx = shsurf->view->geometry.x + cx;
-	cposy = shsurf->view->geometry.y + cy;
-	dposx = rotate->center.x - cposx;
-	dposy = rotate->center.y - cposy;
-	if (dposx != 0.0f || dposy != 0.0f) {
-		weston_view_set_position(shsurf->view,
-					 shsurf->view->geometry.x + dposx,
-					 shsurf->view->geometry.y + dposy);
-	}
-
 	/* Repaint implies weston_surface_update_transform(), which
 	 * lazily applies the damage due to rotation update.
 	 */
@@ -5063,6 +5051,44 @@ map(struct desktop_shell *shell, struct shell_surface *shsurf,
 	}
 }
 
+static void
+shell_surface_adjust_for_transform(struct shell_surface *shsurf)
+{
+	struct weston_matrix *matrix;
+	float cx, cy, cposx, cposy, dposx, dposy, rcx, rcy;
+
+	/* Adjust for rotation transformation */
+	cx = 0.5f * shsurf->surface->width;
+	cy = 0.5f * shsurf->surface->height;
+
+	wl_list_remove(&shsurf->rotation.transform.link);
+	weston_view_geometry_dirty(shsurf->view);
+
+	matrix = &shsurf->rotation.transform.matrix;
+
+	weston_matrix_init(matrix);
+	weston_matrix_translate(matrix, -cx, -cy, 0.0f);
+	weston_matrix_multiply(matrix, &shsurf->rotation.rotation);
+	weston_matrix_translate(matrix, cx, cy, 0.0f);
+
+	wl_list_insert(
+		&shsurf->view->geometry.transformation_list,
+		&shsurf->rotation.transform.link);
+
+	weston_view_to_global_float(shsurf->view, cx, cy, &rcx, &rcy);
+
+	/* Position surface to maintain expected center coordinates */
+	cposx = shsurf->view->geometry.x + cx;
+	cposy = shsurf->view->geometry.y + cy;
+	dposx = rcx - cposx;
+	dposy = rcy - cposy;
+	if (dposx != 0.0f || dposy != 0.0f) {
+		weston_view_set_position(shsurf->view,
+					 shsurf->view->geometry.x + dposx,
+					 shsurf->view->geometry.y + dposy);
+	}
+}
+
 static void
 configure(struct desktop_shell *shell, struct weston_surface *surface,
 	  float x, float y)
@@ -5097,6 +5123,9 @@ configure(struct desktop_shell *shell, struct weston_surface *surface,
 		if (shsurf->state.maximized)
 			surface->output = shsurf->output;
 	}
+
+	if (!wl_list_empty(&shsurf->rotation.transform.link))
+		shell_surface_adjust_for_transform(shsurf);
 }
 
 static void

src/compositor.h

@@ -628,7 +628,7 @@ struct weston_compositor {
 };
 
 /* WESTON_PLUGIN_CALL_SINGLE(compositor, weston_plugin, function, arguments to function)
- * Call a function for a specific plugin */
+ * Call a function for a weston_plugin */
 #define WESTON_PLUGIN_CALL_SINGLE(p, f, ...) ({				\
 	if (p->interface->f)						\
 		p->interface->f(__VA_ARGS__);				\
@@ -640,7 +640,7 @@ struct weston_compositor {
 	struct weston_plugin *p;					\
 									\
 	wl_list_for_each(p, &(c)->plugin_list, link)			\
-		WESTON_PLUGIN_CALL_SINGLE(p, f, __VA_ARGS__);	\
+		WESTON_PLUGIN_CALL_SINGLE(p, f, __VA_ARGS__);		\
 })
 
 struct weston_plugin;

src/wobbly.c

@@ -827,8 +827,8 @@ wobbly_resize_notify(struct weston_view *view)
 
 	ww = ws->ww;
 
-	x = view->geometry.x;
-	y = view->geometry.y;
+	x = ws->x = view->geometry.x;
+	y = ws->y = view->geometry.y;
 	w = ws->width = surface->width;
 	h = ws->height = surface->height;