How To Simulate Expanded and Condensed Fonts

MORE INFORMATION

Condensed or expanded (sometimes called extended) type is an expression of type design. By this definition, true condensed or expanded versions of type are created by a typographer in a separate font file.

Windows applications can simulate the appearance of a condensed or expanded font variation by changing the relative width of the font's logical description. TrueType fonts have variable width glyphs, so the "width" of a font in Windows is referred to as the average character width. The tmAveCharWidth member of the TEXTMETRIC structure gives the average character width for a realized font. This structure is returned by the GetTextMetrics() function.

The width of a TrueType font is controlled by the font's average character width. When creating a font, the lfWidth member of the LOGFONT structure expresses the average character width.

To create a relatively condensed or expanded simulation of a particular font, one should modify the average character width of a previously realized font by a desired condensation or expansion factor. This will ensure that the simulated version of the font looks proportionally correct to the normal version of the typeface's original glyphs.

Use the following steps to create an expanded or condensed simulation of a TrueType font:

1. Create a normal version of a font by specifying the lfHeight of the LOGFONT structure and setting the lfWidth to zero. This creates a font that has the typographer's intended aspect ratio.
2. Next the application retrieves the realized font's average character width from the tmAveCharWidth member of the TEXTMETRIC structure.
3. Create the expanded or condensed font by setting the lfWidth member of the LOGFONT structure to tmAveCharWidth multiplied by some condensation or expansion ratio.

The following sample code implements this technique. The function is a Windows procedure paint function which can be called from the WM_PAINT case of a simple application between the BeginPaint() and EndPaint() functions.

   BOOL OnPaint( HDC hdc, LPLOGFONT plf )
   {
       int         x=0, y=0;           // Output coordinates
       DWORD       AverageWidth;       // Font Width
       HFONT       hFont, hOldFont;    // Font handles
       char        Buffer[200];        // Output strings
       LOGFONT     lf;                 // Logical Font desc.
       TEXTMETRIC  tm;                 // Actual Font metrics

       /* Make a copy of the Logical Description so we can 
          make modifications */ 
       lf = *plf;

       /* 
        * Create a Normal font for comparison 
        */ 

       hFont = CreateFontIndirect( &lf );
       hOldFont = SelectObject( hdc, hFont );
       GetTextMetrics( hdc, &tm );

       /* Save off the "width" of the font to use later */ 
       AverageWidth = tm.tmAveCharWidth;

       /* properly output the text */ 
       y += tm.tmExternalLeading;
       wsprintf( Buffer, 
           "This is Normal text for %s.", 
           lf.lfFaceName );
       TextOut( hdc, x, y, Buffer, lstrlen( Buffer ) );

       /* advance for next line and cleanup */ 
       y += tm.tmHeight;
       SelectObject( hdc, hOldFont );
       DeleteObject( hFont );


       /* 
        * Create a condensed font for output 
        */ 

       /* Define our condensed font as half the original */ 
       lf.lfWidth = AverageWidth/2;    

       hFont = CreateFontIndirect( &lf );
       hOldFont = SelectObject( hdc, hFont );
       GetTextMetrics( hdc, &tm );

       /* properly output the text */ 
       y += tm.tmExternalLeading;
       wsprintf( Buffer, 
           "This is Condensed text for %s.", 
           lf.lfFaceName );
       TextOut( hdc, x, y, Buffer, lstrlen( Buffer ) );

       /* advance for next line and cleanup */ 
       y += tm.tmHeight;
       SelectObject( hdc, hOldFont );
       DeleteObject( hFont );


       /* 
        * Create an expanded font for output 
        */ 

       /* Define our expanded font as twice the original */ 
       lf.lfWidth = AverageWidth*2;    

       hFont = CreateFontIndirect( &lf );
       hOldFont = SelectObject( hdc, hFont );
       GetTextMetrics( hdc, &tm );

       /* properly output the text */ 
       y += tm.tmExternalLeading;
       wsprintf( Buffer, 
           "This is Expanded text for %s.", 
           lf.lfFaceName );
       TextOut( hdc, x, y, Buffer, lstrlen( Buffer ) );

       /* cleanup */ 
       SelectObject( hdc, hOldFont );
       DeleteObject( hFont );

       return TRUE;
   }