freetype2/include/freetype/ftbdf.h

/****************************************************************************
 *
 * ftbdf.h
 *
 *   FreeType API for accessing BDF-specific strings (specification).
 *
 * Copyright (C) 2002-2021 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */


#ifndef FTBDF_H_
#define FTBDF_H_

#include <freetype/freetype.h>

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif


FT_BEGIN_HEADER


  /**************************************************************************
   *
   * @section:
   *   bdf_fonts
   *
   * @title:
   *   BDF and PCF Files
   *
   * @abstract:
   *   BDF and PCF specific API.
   *
   * @description:
   *   This section contains the declaration of functions specific to BDF and
   *   PCF fonts.
   *
   */


  /**************************************************************************
   *
   * @enum:
   *    BDF_PropertyType
   *
   * @description:
   *    A list of BDF property types.
   *
   * @values:
   *    BDF_PROPERTY_TYPE_NONE ::
   *      Value~0 is used to indicate a missing property.
   *
   *    BDF_PROPERTY_TYPE_ATOM ::
   *      Property is a string atom.
   *
   *    BDF_PROPERTY_TYPE_INTEGER ::
   *      Property is a 32-bit signed integer.
   *
   *    BDF_PROPERTY_TYPE_CARDINAL ::
   *      Property is a 32-bit unsigned integer.
   */
  typedef enum  BDF_PropertyType_
  {
    BDF_PROPERTY_TYPE_NONE     = 0,
    BDF_PROPERTY_TYPE_ATOM     = 1,
    BDF_PROPERTY_TYPE_INTEGER  = 2,
    BDF_PROPERTY_TYPE_CARDINAL = 3

  } BDF_PropertyType;


  /**************************************************************************
   *
   * @type:
   *    BDF_Property
   *
   * @description:
   *    A handle to a @BDF_PropertyRec structure to model a given BDF/PCF
   *    property.
   */
  typedef struct BDF_PropertyRec_*  BDF_Property;


  /**************************************************************************
   *
   * @struct:
   *    BDF_PropertyRec
   *
   * @description:
   *    This structure models a given BDF/PCF property.
   *
   * @fields:
   *    type ::
   *      The property type.
   *
   *    u.atom ::
   *      The atom string, if type is @BDF_PROPERTY_TYPE_ATOM.  May be
   *      `NULL`, indicating an empty string.
   *
   *    u.integer ::
   *      A signed integer, if type is @BDF_PROPERTY_TYPE_INTEGER.
   *
   *    u.cardinal ::
   *      An unsigned integer, if type is @BDF_PROPERTY_TYPE_CARDINAL.
   */
  typedef struct  BDF_PropertyRec_
  {
    BDF_PropertyType  type;
    union {
      const char*     atom;
      FT_Int32        integer;
      FT_UInt32       cardinal;

    } u;

  } BDF_PropertyRec;


  /**************************************************************************
   *
   * @function:
   *    FT_Get_BDF_Charset_ID
   *
   * @description:
   *    Retrieve a BDF font character set identity, according to the BDF
   *    specification.
   *
   * @input:
   *    face ::
   *      A handle to the input face.
   *
   * @output:
   *    acharset_encoding ::
   *      Charset encoding, as a C~string, owned by the face.
   *
   *    acharset_registry ::
   *      Charset registry, as a C~string, owned by the face.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   This function only works with BDF faces, returning an error otherwise.
   */
  FT_EXPORT( FT_Error )
  FT_Get_BDF_Charset_ID( FT_Face       face,
                         const char*  *acharset_encoding,
                         const char*  *acharset_registry );


  /**************************************************************************
   *
   * @function:
   *    FT_Get_BDF_Property
   *
   * @description:
   *    Retrieve a BDF property from a BDF or PCF font file.
   *
   * @input:
   *    face ::
   *      A handle to the input face.
   *
   *    name ::
   *      The property name.
   *
   * @output:
   *    aproperty ::
   *      The property.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   This function works with BDF _and_ PCF fonts.  It returns an error
   *   otherwise.  It also returns an error if the property is not in the
   *   font.
   *
   *   A 'property' is a either key-value pair within the STARTPROPERTIES
   *   ... ENDPROPERTIES block of a BDF font or a key-value pair from the
   *   `info->props` array within a `FontRec` structure of a PCF font.
   *
   *   Integer properties are always stored as 'signed' within PCF fonts;
   *   consequently, @BDF_PROPERTY_TYPE_CARDINAL is a possible return value
   *   for BDF fonts only.
   *
   *   In case of error, `aproperty->type` is always set to
   *   @BDF_PROPERTY_TYPE_NONE.
   */
  FT_EXPORT( FT_Error )
  FT_Get_BDF_Property( FT_Face           face,
                       const char*       prop_name,
                       BDF_PropertyRec  *aproperty );

  /* */

FT_END_HEADER

#endif /* FTBDF_H_ */


/* END */