isRectVisible method
Checks if a world coordinate rectangle intersects with the viewport.
Use this for visibility culling to determine if a node or element should be rendered.
Parameters:
worldRect: The rectangle to check in world/graph coordinates
Returns true if any part of the rectangle overlaps the viewport, false otherwise.
Implementation
bool isRectVisible(Rect worldRect) {
return viewportExtent.overlaps(worldRect);
}