In this video from Bisqwit, the selected line is colored by a gradient according to column number. Image is below. He implemented the gradient in a custom terminal emulator. Is there any way to recreate it with a Vim plugin?
Vim (and neovim) use some highlighting groups (
:h highlight-groups) to define which color a UI component should have.
For the cursor line the group is
Such groups can only contain one color and the code is not made to support the kind of customization you are looking for. So the answer is: it is not possible to recreate that in a vim plugin.
Maybe this could be done by reworking heavily the source code but I don't see such a patch being merged into Vim (maybe into neovim but even there I'm really not sure).