htop "Display options -> shadow other users' processes" returns black on black for TERM=linux-16color on a Linux console (tty)

[fasterit]

Debian bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=793106

Reproducible by:

1. switch to a Linux console (virtual terminal, e.g. ALT-CTRL F1)
2. log in
3. run TERM=linux-16color htop
4. enable "Setup -> Display options -> shadow other users' processes"
5. you see other users' processes black on black unless highlighted

Can this be fixed in the curses magic htop uses or via a work-around or (least desirably) mentioned in the documentation?

[hishamhm]

Please run this test program:

/* color.c */
#include <curses.h>

int main(void) {
    initscr();
    start_color();
    //init_color(8, 500, 500, 500); /* disabled line */

    printw("Can change colors? %c\n", can_change_color() ? 'Y' : 'N');
    for (int i = 0; i <= 15; i++) {
        init_pair(i+2, i, 0);
        attron(COLOR_PAIR(i+2));
        printw("Color %d!\n", i);
        attron(A_BOLD);
        printw("Bold color %d %d!\n", i, COLOR_PAIRS);
        attroff(A_BOLD);
    }
    refresh();

    getch();

    endwin();
}

Compile it with gcc -o color color.c -lncursesw

and run it with and without TERM=linux-16color.

Which colors, if any, appear as dark gray (and in which mode)? Sending images of your results would also be helpful. (If taking a screenshot from the console is problematic, you can take pictures from your phone :) )

If color 8 appears as cyan when running with TERM=linux-16color, try removing the // from the line marked disabled line and recompiling, and let me know if it makes any difference.

I got some weird results in my machine (which would require some ugly workarounds in htop), and I'd like to see if the results are at least consistent across machines/distros.

[fasterit]

fbcat makes nice screenshots from the framebuffer linux consoles.
I did not comment in your line as per instructions. I hope I understood these correctly.
Kind regards,
Daniel

TERM=linux

TERM=linux-16color

[hishamhm]

Got it, thanks!

Interesting results! They look different than what I got in my system, but they look compatible to the tweak I implemented.

Please try this branch, fixedgray:

git clone --branch fixedgray https://github.com/hishamhm/htop
cd htop
./autogen.sh
./configure
make
./htop

Hopefully it fixes the behavior of gray. It may even obsolete the "Broken Gray" mode!

[fasterit]

Yes, that works much better. Gray text (like the "other users' processes" but also in the header section on the gauges) is now readable very well under TERM=linux-16color.
Confirmed working for Linux console (tty), gnome-terminal and xcfe4-terminal.
Thank you!
/DLange

[hishamhm]

@fasterit Excellent, thank you!