# Objective
We switch back and forwards between logical and physical coordinates all
over the place. Systems have to query for cameras and the UiScale when
they shouldn't need to. It's confusing and fragile and new scale factor
bugs get found constantly.
## Solution
* Use physical coordinates whereever possible in `bevy_ui`.
* Store physical coords in `ComputedNode` and tear out all the unneeded
scale factor calculations and queries.
* Add an `inverse_scale_factor` field to `ComputedNode` and set nodes
changed when their scale factor changes.
## Migration Guide
`ComputedNode`'s fields and methods now use physical coordinates.
`ComputedNode` has a new field `inverse_scale_factor`. Multiplying the
physical coordinates by the `inverse_scale_factor` will give the logical
values.
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Co-authored-by: atlv <email@atlasdostal.com>