Add possibility to get terminal default foreground and background colors

[PavelTurk]

I searched through the code but couldn't find a way to retrieve the default background/foreground colors of the terminal. At the same time, for Windows, as I understand, the colors are defined -

jline3/terminal-jna/src/main/java/org/jline/terminal/impl/jna/win/WindowsAnsiWriter.java

Line 90 in 46bd37d

originalColors = info.wAttributes;

That's why I suggest to add this feature.

[gnodet]

Have you tried using Terminal.getPalette() ?

[PavelTurk]

@gnodet Yes, I tried. It returns palette from which you can get concrete color by index. But I didn't a way to find out the index of the foreground color and the index of the background color.

[gnodet]

This way is very Windows specific. On XTerm, it can be retrieved using echo "\033]10;?\033\\" and echo "\033]11;?\033\\".
A single API to support both from the Palette would be needed somehow.