Visual render tree, logical widget tree. In Flutter, the render
tree operates in a device-independent, visual coordinate system,
which means smaller values in the x coordinate are always towards
the left, even if the current reading direction is right-to-left.
The widget tree typically operates in logical coordinates, meaning
with start and end values whose visual interpretation depends
on the reading direction. The transformation from logical to visual
coordinates is done in the handoff between the widget tree and the
render tree. This approach is more efficient because layout and
painting calculations in the render tree happen more often than the
widget-to-render tree handoff and can avoid repeated coordinate conversions.