Console program with color output?

[neilms]

Hi,
I am testing a console program written in C++. I want to adjust the output so that instead of the standard white text, I can make certain words appear in different colors. So for example, the following string will output each word in (for example) the following colours:

This is a test

This - appears as blue text
is - appears as red text
a - appears as green text
test - appears as yellow text.

Can anyone tell me what header files would I need to include doing this under the console? Alternatively, could you point me to a program that might have some useful code that achieves a similar effect? Note, I am not using X windows at all for this project.

 

[wblock@]

These are ANSI color codes. There are programs in ports that use them. textproc/codespell, for example.

 

[fonz]

I want to adjust the output so that instead of the standard white text, I can make certain words appear in different colors.

There's also devel/ncurses. Although for the sole purpose of colouring the output it's probably a bit too much (try the ANSI codes first), it's a useful library that you may want to use later for e.g. menus, TUIs and that sort of thing.

 

[expl]

Keep in mind that if you want your output to be pipe friendly you have to detect if your program is not running on a TTY and disable any special characters that TTY would normally escape.

 

[fonz]

Keep in mind that if you want your output to be pipe friendly you have to detect if your program is not running on a TTY and disable any special characters that TTY would normally escape.

Good point. You (=OP) may want to have a look at the source of e.g. ls(1) (-G option) to see how this is done.

 

[wblock@]

Keep in mind that if you want your output to be pipe friendly you have to detect if your program is not running on a TTY and disable any special characters that TTY would normally escape.

Or make the ANSI color output an option. I did that in textproc/igor. less(1) will show ANSI color codes if given the -R option.

 

[neilms]

Or make the ANSI color output an option. I did that in textproc/igor. less(1) will show ANSI color codes if given the -R option.

Can you show the function / code that:
1 - parse the command line argument &
2. -how it links to the ansi code?

 

[wblock@]

Can you show the function / code that:
1 - parse the command line argument &

That depends on the language. igor is in Perl.

2. -how it links to the ansi code?

Look up the ANSI color sequence to use, print them out as characters.

% printf "\033[1;31mThis is red \033[1;34mand this is blue.\033[0;24;27m\n"
[color="Red"]This is red [/color][color="Blue"]and this is blue.[/color]

 

[neilms]

It's ok - I have a C++ solution that I found. It is quite simple really:

#include <iostream>
    
     using namespace std;
     
     int main (int argc, char const *argv[]) {
       const char COL_RESET[] = "\x1b[0m";
       
       // Foreground colors are in form of 3x, bacground are 4x
      const char RED[]     = "\x1b[31m";
      const char GREEN[]   = "\x1b[32m";
      const char YELLOW[]  = "\x1b[33m";
      const char BLUE[]    = "\x1b[34m";
      const char MAGENTA[] = "\x1b[35m";
      const char CYAN[]    = "\x1b[36m";
    
      cout << RED     << "Red looks good" << endl;
      cout << GREEN   << "Green looks good" << endl;
      cout << YELLOW  << "Yellow looks good" << endl;
      cout << BLUE    << "Blue looks good" << endl;
      cout << MAGENTA << "Magenta looks good" << endl;
      cout << CYAN    << "Cyan looks good" << COL_RESET << endl;
      cout << "This text should have the normal color" << endl;
      
      // American flag, ASCII style.
      cout << "\x1b[44m" << "*********" 
           << "\x1b[41m" << "=================" << endl;
      cout << "\x1b[44m" << "*********" 
           << "\x1b[41m" << "=================" << endl;
      cout << "\x1b[44m" << "*********" 
           << "\x1b[41m" << "=================" << endl;
      cout << "\x1b[44m" << "*********" 
           << "\x1b[41m" << "=================" << endl;
      cout << "==========================" << endl;
      cout << "==========================" << endl;
      cout << "==========================" << COL_RESET << endl;
  
      return 0;
    }

As for the command line arguments - boost library offers ready made 'program_options' functions though C users might use gnu getopt.

 

[fonz]

As for the command line arguments - boost library offers ready made 'program_options' functions though C users might use gnu getopt.

They might not necessarily be mutually exclusive. For example, getopt(3) can also be used after certain x11-toolkits/libXt functions in order to first process X-specific options (e.g. -geometry) and then the rest. It wouldn't surprise me if boost options and getopt(3) can be combined too (when done right).