HOWTO: Modify the Intercharacter Spacing Array for a String (263536)

MORE INFORMATION

The code below demonstrates how to use the GetCharABCWidths function to determine the default intercharacter spacing array for a string, and how to modify that array to alter the spacing of the text.

This code was designed to work with 8-bit ANSI strings or, when compiling for Unicode, with Unicode strings. Double-byte character set (DBCS) strings require more processing. Also, new applications should use Uniscribe, which is described in the MSJ article in the "References" section.

BOOL ModifiedTextOut( HDC hDC, int nX, int nY, LPTSTR szString )
{
	int		i, nStringLength;
	BOOL	bResult;
	int		*pDx;

	// How long is the string - we need this a couple times below
	nStringLength = lstrlen( szString );

	// Allocate enough memory for the intercharacter spacing (ICS).array
	pDx = (int *)malloc( sizeof(int) * nStringLength );
	// Initialize the ICS array with "default" values
	for(i=0;i<nStringLength;i++)
	{
		ABC		abc;
		if( ! GetCharABCWidths( hDC, szString[i], szString[i], &abc ) )
		{
			free( pDx );
			return FALSE;
		}
		pDx[i] = abc.abcA + abc.abcB + abc.abcC;
	}

   // To demonstrate the modification of the ICS array, just add
   // one logical unit to the spacing for each character. This is where
   // you'd do things like implement justification, etc. by modifying
   // this array to cause the string to have the extent you desire.
        for(i=0;i<nStringLength;i++)
	{
		pDx[i] += 1;
	}
	// ExtTextOut() draws our text with our ICS array.
	bResult = ExtTextOut( hDC, nX, nY, ETO_OPAQUE, NULL, szString, nStringLength, pDx );
	// clean up.
	free( pDx );
	return bResult;
}