ui: avoid rendering off-viewport items in Scroller (#36659)

avoid rendering off-viewport items in Scroller

Author: deanlee

system/ui/widgets/scroller.py

@@ -161,7 +161,6 @@ def _get_scroll(self, visible_items: list[Widget], content_size: float) -> float
     return self.scroll_panel.get_offset()
 
   def _render(self, _):
-    # TODO: don't draw items that are not in the viewport
     visible_items = [item for item in self._items if item.is_visible]
 
     # Add line separator between items
@@ -219,6 +218,10 @@ def _render(self, _):
       item.set_position(round(x), round(y))  # round to prevent jumping when settling
       item.set_parent_rect(self._rect)
 
+      # Skip rendering if not in viewport
+      if not rl.check_collision_recs(item.rect, self._rect):
+        continue
+
       # Scale each element around its own origin when scrolling
       scale = self._zoom_filter.x
       rl.rl_push_matrix()