Thread: Writing Background RGB to file

In my program the user can change the background color. I'm trying to write the RGB information to the log file, but I have no Idea how to write it so i can load it later when the application is ran again. I am using the stdio.h functions to access the logfile.

Please Help. Thanks in advance..

Look in to fread, fwrite, fopen, fclose, and the FILE* data type.

is your problem
* you don't know how to read/write from/to files in general or
* just how to store the RGB value?

i remembered i once wrote RGB-to-string and string-to-RGB code
for my ColorPicker EmEditor Plugin. full source can be found
on my website, the RGB part is attached. i hope that helps.

Code:

//////////////////////////////////////////////////////////////
///  TCHARs to RGB
//////////////////////////////////////////////////////////////


COLORREF incol = 0;
bool bIncolValid = true;
for( UINT u = 0; u < 6; u++ )
{
	TCHAR ch = *( in + u );

	if(
		( ch >= _T( '0' ) ) &&
		( ch <= _T( '9' ) )
	)
	{
		incol +=	( ch - _T( '0' ) +  0 )
						<< ( ( ( ( u >> 1 ) << 1 ) + ( ( u + 1 ) & 1 ) ) << 2 );
	}
	else if(
		( ch >= _T( 'A' ) ) &&
		( ch <= _T( 'F' ) )
	)
	{
		incol +=	( ch - _T( 'A' ) + 10 )
						<< ( ( ( ( u >> 1 ) << 1 ) + ( ( u + 1 ) & 1 ) ) << 2 );
	}
	else if(
		( ch >= _T( 'a' ) ) &&
		( ch <= _T( 'f' ) )
	)
	{
		incol +=	( ch - _T( 'a' ) + 10 )
						<< ( ( ( ( u >> 1 ) << 1 ) + ( ( u + 1 ) & 1 ) ) << 2 );
	}
	else
	{
		bIncolValid = false;

		break;
	}
}

Code:

//////////////////////////////////////////////////////////////
///  RGB to TCHARs
//////////////////////////////////////////////////////////////


// 0x00bbggrr
TCHAR out[ 7 ];
TCHAR red[ 3 ];
TCHAR green[ 3 ];
TCHAR blue[ 3 ];

_itot( GetRValue( cc.rgbResult ), red, 16 );
_itot( GetGValue( cc.rgbResult ), green, 16 );
_itot( GetBValue( cc.rgbResult ), blue, 16 );


// RED
if( red[ 1 ] == _T( '\0' ) )
{
	out[ 0 ] = _T( '0' );
	out[ 1 ] = red[ 0 ];
}
else
{
	out[ 0 ] = red[ 0 ];
	out[ 1 ] = red[ 1 ];
}


// GREEN
if( green[ 1 ] == _T( '\0' ) )
{
	out[ 2 ] = _T( '0' );
	out[ 3 ] = green[ 0 ];
}
else
{
	out[ 2 ] = green[ 0 ];
	out[ 3 ] = green[ 1 ];
}


// BLUE
if( blue[ 1 ] == _T( '\0' ) )
{
	out[ 4 ] = _T( '0' );
	out[ 5 ] = blue[ 0 ];
}
else
{
	out[ 4 ] = blue[ 0 ];
	out[ 5 ] = blue[ 1 ];
}


out[ 6 ] = _T( '\0' );

Originally Posted by jverkoey

Look in to fread, fwrite, fopen, fclose, and the FILE* data type.

Well I kne wthat already
Thanks for replying guys. I figured It out on my own after jverkoey posted. I made a small system for it.

Writing the values:

Code:

FILE *LogFile;
LogFile = fopen("Color.cfg","w");
fputc(GetRValue(cc.rgbResult),LogFile);
fprintf(LogFile,"\n");
fputc(GetGValue(cc.rgbResult),LogFile);
fprintf(LogFile,"\n");
fputc(GetBValue(cc.rgbResult),LogFile);
fclose(LogFile);

Loading the values:

Code:

if(fopen("Color.cfg","r") != 0)
{      
        FILE *LogFile;
        LogFile = fopen("Color.cfg","r");
        int rv,gv,bv;
        rv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        gv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        bv = fgetc(LogFile);
        wincl.hbrBackground = (HBRUSH)CreateSolidBrush(RGB(rv,gv,bv));
}

shouldnt:

Code:

if(fopen("Color.cfg","r") != 0)
{      
        FILE *LogFile;
        LogFile = fopen("Color.cfg","r");
        int rv,gv,bv;
        rv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        gv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        bv = fgetc(LogFile);
        wincl.hbrBackground = (HBRUSH)CreateSolidBrush(RGB(rv,gv,bv));
}

be:

Code:

FILE *LogFile;
LogFile = fopen("Color.cfg","r");

if(LogFile != 0)
{      
        int rv,gv,bv;
        rv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        gv = fgetc(LogFile);
        fscanf(LogFile,"\n");
        bv = fgetc(LogFile);
        wincl.hbrBackground = (HBRUSH)CreateSolidBrush(RGB(rv,gv,bv));
}

fclose(LogFile);

Just wondering why you put two calls to fopen..

I have other "If" statements that open the file for different operations. Some are reeding some are writing. I also get Access violations when I do it that way.

i remembered i once wrote RGB-to-string and string-to-RGB code for my ColorPicker EmEditor Plugin. full source can be found on my website, the RGB part is attached. i hope that helps.

How about:

Code:

//////////////////////////////////////////////////////////////
///  RGB to TCHARs
//////////////////////////////////////////////////////////////

_stprintf(out, _T("%02X%02X%02X"), GetRValue(rgb), GetGValue(rgb), GetBValue(rgb));

//////////////////////////////////////////////////////////////
///  TCHARs to RGB
//////////////////////////////////////////////////////////////

int r, g, b;
if (3 == _stscanf(in, _T("%2x%2x%2x"), &r, &g, &b))
{
    col = RGB(r, g, b);
}
else
{
    valid = false;
}

if that code worx - i guess so - i wasted a lot if time. :-(