• readme

  •                   FreeType font driver for PCF fonts
    
                           Francesco Zappa Nardelli
                      <francesco.zappa.nardelli@ens.fr>
    
    
    Introduction
    ************
    
    PCF (Portable Compiled Format) is a binary bitmap font format, largely used
    in X world. This code implements a PCF driver for the FreeType library.
    Glyph images are loaded into memory only on demand, thus leading to a small
    memory footprint.
    
    Informations on the PCF font format can only be worked out from
    ``pcfread.c'', and ``pcfwrite.c'', to be found, for instance, in the XFree86
    (www.xfree86.org) source tree (xc/lib/font/bitmap/).
    
    Many good bitmap fonts in bdf format come with XFree86: they can be
    compiled into the pcf format using the ``bdftopcf'' utility.
    
    
    Supported hardware
    ******************
    
    The driver has been tested on linux/x86 and sunos5.5/sparc.  In both
    cases the compiler was gcc.  When back in Paris, I will test it also
    on linux/alpha.
    
    
    Encodings
    *********
    
    The variety of encodings that accompanies pcf fonts appears to encompass the
    small set defined in freetype.h.  On the other hand, each pcf font defines
    two properties that specify encoding and registry.
    
    I decided to make these two properties directly accessible, leaving to the
    client application the work of interpreting them.  For instance:
    
      #include "pcftypes.h"  /* include/freetype/internal/pcftypes.h */
    
      FT_Face     face;
      PCF_Public_Face  pcfface;
    
      FT_New_Face( library,..., &face );
    
      pcfface = (PCF_Public_Face)face;
      
      if ((pcfface->charset_registry == "ISO10646") && 
            (pcfface->charset_encoding) == "1")) [..]
    
    Thus the driver always export ``ft_encoding_none'' as
    face->charmap.encoding.  FT_Get_Char_Index() behavior is unmodified, that
    is, it converts the ULong value given as argument into the corresponding
    glyph number.
    
    
    Known problems
    **************
    
    - dealing explicitly with encodings breaks the uniformity of freetype2
      api.
    
    - except for encodings properties, client applications have no
      visibility of the PCF_Face object.  This means that applications
      cannot directly access font tables and are obliged to trust
      FreeType.
    
    - currently, glyph names and ink_metrics are ignored.
    
    I plan to give full visibility of the PCF_Face object in the next
    release of the driver, thus implementing also glyph names and
    ink_metrics.
    
    - height is defined as (ascent - descent).  Is this correct?
    
    - if unable to read size informations from the font, PCF_Init_Face
      sets available_size->width and available_size->height to 12.
    
    - too many english grammar errors in the readme file :-(
    
    
    License
    *******
    
    Copyright (C) 2000 by Francesco Zappa Nardelli
    
    Permission is hereby granted, free of charge, to any person obtaining
    a copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including
    without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to
    the following conditions:
    
    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    
    
    Credits
    *******
    
    Keith Packard wrote the pcf driver found in XFree86.  His work is at
    the same time the specification and the sample implementation of the
    PCF format.  Undoubtedly, this driver is inspired from his work.