Allow plugins to change foreground text color through manually adding regions

[DanielRosenwasser]

The TypeScript Language Service has an API for getting "classification ranges" of a source file, which are intended to be used for colorization in editors.

A mapping of classifications to Sublime regions seems to be fairly trivial, and so it would appear that the Sublime API would make this easy; however, the foreground color of the text does not seem to change when using add_regions.

I'm not sure if this is an intentional limitation (using build 3083), but it would allow us to focus on other features for our Sublime plugin instead of maintaining a separate grammar file.

[FichteFoll]

Just for the record: There is a workaround for that, which is as follows (inspired by https://github.com/whitequark/rainbowth).

1. Read the color scheme file and determine background color.
2. Artificially determine a new background color that is (marginally) different from the original one, e.g. '#%06x' % max(1, (int(bg[1:], 16) - 1)), with #000001 for when background is black. Otherwise ST will ignore it and behave as if no background color was set.
3. Create a new scope in the color scheme with the above color as background and any color as foreground.
4. Either overwrite existing color scheme (bad) or save new color scheme to a different place and adjust color_scheme setting accordingly.
5. Use the new scope name with view.add_regions.

Just be careful with the color_scheme setting, i.e. consider the user changing it during runtime and restore the original one when the plugin is disabled/removed. I had to do similar but even more complex things here: https://github.com/SublimeText/InactivePanes/

[DanielRosenwasser]

Thanks for the response @FichteFoll! I think this is definitely something we may look into. We'll try to keep you posted on how well it works out with the work-around.

@steveluc @billti @mhegazy

[donysukardi]

Any update on this? I was looking into styling ANSI colors with regions just to realize that I couldn't get Sublime to set just the foreground color. It would end up being reversed as the background as mentioned.

[FichteFoll]

@donysukardi No update.

You might want to check out https://packagecontrol.io/packages/ANSIescape though.

[rwols]

I will need this for LSP's semantic highlighting. Or whatever alternative API.

[eerohele]

My use case is that I need to disable syntax highlighting for a set of regions. It's currently rather unwieldy.