Re: Need your help with MinGW Issue 17: --color options don't work (produce garbage)

From: Reece Dunn <msclrhd@googlemail.com>
Date: Aug 15, 2007, 07:32 UTC
Message-ID: <3f4fd2640708150032l7441b285mc2cc9e22702bce21@mail.gmail.com>
In-Reply-To: <a1bbc6950708142329w4e0e3d7cq573c67dd3b28f03a@mail.gmail.com>

On 15/08/07, Dmitry Kakurin wrote:

Show 16 quoted lines

> Here are the facts:
>
> 'git branch --color' produces garbage:
> $ git branch --color
>   devel←[m
>   dima←[m
>   dmitryk←[m
> * ←[32mmaster←[m
>   mob←[m
>   next←[m
>
> 'git branch --color | cat' produces expected colored output.
>
> I've traced it down to printf statement in gdb and it sends the right
> esc-sequence.
> Where should I look next?

Windows doesn't recognise the *nix printf colour codes.

Piping through cat will be going through cygwin/mingw emulation, translating the colour codes to the correct API calls.

You need to call the SetConsoleTextAttribute Win32 API. For example:

#ifdef defined(WIN32) || defined(WIN64)

typedef WORD color_t;

color_t red = FOREGROUND_INTENSITY | FOREGROUND_RED; color_t green = FOREGROUND_INTENSITY | FOREGROUND_GREEN; color_t blue = FOREGROUND_INTENSITY | FOREGROUND_BLUE;

color_t white = red | green | blue;

void set_color( color_t color )
{
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), color );
}

#else

typedef const char * color_t;

color_t red = ...; ...

void set_color( color_t color ){ printf( color ); }

#endif

That way, you can do things like:
    set_color( red );
    printf( ... );
    set_color( blue );

This is not as pretty as the existing codebase, so another possibility would be to create wrappers around the console output functions (i.e. printf) and call SetConsoleTextAttribute there. This way, you can restore the old colour when a restore settings sequence is intercepted. It is also possible to reuse the GetStdHandle return value.

NOTE: There isn't a GetConsoleTextAttribute in the Windows API, but
Google found this:

#if ( (defined(WIN32) || defined(_WINDOWS)) && !defined(__CYGWIN__) ) && defined(_CONSOLE)

static WORD GetConsoleTextAttribute(HANDLE Console)
{
    CONSOLE_SCREEN_BUFFER_INFO ConsoleInfo;
    GetConsoleScreenBufferInfo(Console, &ConsoleInfo);
    return ConsoleInfo.wAttributes;
}

#endif

HTH,
- Reece