# Objective
The false and true arguments for the select statement in `lerp_hue_long`
are misordered, resulting in it taking the wrong hue path:
## Solution
Swap the arguments around.
Also fixed another case I found during testing. The hue was interpolated
even when it is undefined for one of the endpoints (for example in a
gradient from black to yellow). In those cases it shouldn't interpolate,
instead it should return the hue of the other end point.
## Testing
I added a `linear_gradient` module to the testbed `ui` example, run
with:
```
cargo run --example testbed_ui
```
In the linear gradients screen (press space to switch) it shows a column
of red to yellow linear gradients. The last gradient in the column uses
the OKLCH long path, which should look like this:
matching the same gradient in CSS:
https://jsfiddle.net/fevshkdy/14/
if the correct hue path is chosen.
5e3927ba48