CODEWITHSUNDEEP
ccommand-linewindowncurses
qwertz
qwertz

Reputation: 14792

ncurses multi colors on screen

I want to make a menu with ncurses.h and more than one color. I mean something like this:

┌────────────────────┐
│░░░░░░░░░░░░░░░░░░░░│ <- color 1
│▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│ <- color 2
└────────────────────┘

But if I use init_pair(), attron()and attroff() the color of the whole screen is the same, and not like I've expected.

initscr();

init_pair(0, COLOR_BLACK, COLOR_RED);
init_pair(1, COLOR_BLACK, COLOR_GREEN);

attron(0);
printw("This should be printed in black with a red background!\n");
refresh();

attron(1);
printw("And this in a green background!\n");
refresh()    

sleep(2);

endwin();

What's wrong with this code?

Thanks for every answer!

Upvotes: 15

Views: 40931

Answers (2)

Michael Slade
Michael Slade

Reputation: 13877

Here's a working version:

#include <curses.h>

int main(void) {
    initscr();
    start_color();

    init_pair(1, COLOR_BLACK, COLOR_RED);
    init_pair(2, COLOR_BLACK, COLOR_GREEN);

    attron(COLOR_PAIR(1));
    printw("This should be printed in black with a red background!\n");

    attron(COLOR_PAIR(2));
    printw("And this in a green background!\n");
    refresh();

    getch();

    endwin();
}

Notes:

  • you need to call start_color() after initscr() to use color.
  • you have to use the COLOR_PAIR macro to pass a color pair allocated with init_pair to attron et al.
  • you can't use color pair 0.
  • you only have to call refresh() once, and only if you want your output to be seen at that point, and you're not calling an input function like getch().

This HOWTO is very helpful.

Upvotes: 28

Morpfh
Morpfh

Reputation: 4093

You need to initialize colors and use the COLOR_PAIR macro.

Color pair 0 is reserved for default colors so you have to start your indexing at 1.

....

initscr();
start_color();

init_pair(1, COLOR_BLACK, COLOR_RED);
init_pair(2, COLOR_BLACK, COLOR_GREEN);

attron(COLOR_PAIR(1));
printw("This should be printed in black with a red background!\n");

....

Upvotes: 2

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