ftsizes.h

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  ftsizes.h                                                              */
/*                                                                         */
/*    FreeType size objects management (specification).                    */
/*                                                                         */
/*  Copyright 1996-2001 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.                                        */
/*                                                                         */
/***************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* Typical application would normally not need to use these functions.   */
  /* However, they have been placed in a public API for the rare cases     */
  /* where they are needed.                                                */
  /*                                                                       */
  /*************************************************************************/


#ifndef __FTSIZES_H__
#define __FTSIZES_H__


#include <ft2build.h>
#include FT_FREETYPE_H


FT_BEGIN_HEADER


  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    sizes_management                                                   */
  /*                                                                       */
  /* <Title>                                                               */
  /*    Size management                                                    */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*    Managing multiple sizes per face                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    When creating a new face object (e.g. with @FT_New_Face), an       */
  /*    @FT_Size object is automatically created and used to store all     */
  /*    pixel-size dependent information, available in the "face->size"    */
  /*    field.                                                             */
  /*                                                                       */
  /*    It is however possible to create more sizes for a given face,      */
  /*    mostly in order to manage several character pixel sizes of the     */
  /*    same font family and style.  See @FT_New_Size and @FT_Done_Size.   */
  /*                                                                       */
  /*    Note that @FT_Set_Pixel_Sizes and @FT_Set_Character_Size only      */
  /*    modify the contents of the current "active" size; you thus need    */
  /*    to use @FT_Activate_Size to change it.                             */
  /*                                                                       */
  /*    99% of applications won't need the functions provided here,        */
  /*    especially if they use the caching sub-system, so be cautious      */
  /*    when using these.                                                  */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_New_Size                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Creates a new size object from a given face object.                */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face :: A handle to a parent face object.                          */
  /*                                                                       */
  /* <Output>                                                              */
  /*    asize :: A handle to a new size object.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    You need to call @FT_Activate_Size in order to select the new size */
  /*    for upcoming calls to @FT_Set_Pixel_Sizes, @FT_Set_Char_Size,      */
  /*    @FT_Load_Glyph, @FT_Load_Char, etc.                                */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FT_New_Size( FT_Face   face,
               FT_Size*  size );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Done_Size                                                       */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Discards a given size object.                                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    size :: A handle to a target size object.                          */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FT_Done_Size( FT_Size  size );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Activate_Size                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Even though it is possible to create several size objects for a    */
  /*    given face (see @FT_New_Size for details), functions like          */
  /*    @FT_Load_Glyph or @FT_Load_Char only use the last-created one to   */
  /*    determine the "current character pixel size".                      */
  /*                                                                       */
  /*    This function can be used to "activate" a previously created size  */
  /*    object.                                                            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    size :: A handle to a target size object.                          */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    If "face" is the size's parent face object, this function changes  */
  /*    the value of "face->size" to the input size handle.                */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FT_Activate_Size( FT_Size  size );

  /* */


FT_END_HEADER

#endif /* __FTSIZES_H__ */


/* END */