ftglyph.h

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  ftglyph.h                                                              */
/*                                                                         */
/*    FreeType convenience functions to handle glyphs (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.                                        */
/*                                                                         */
/***************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* This file contains the definition of several convenience functions    */
  /* that can be used by client applications to easily retrieve glyph      */
  /* bitmaps and outlines from a given face.                               */
  /*                                                                       */
  /* These functions should be optional if you are writing a font server   */
  /* or text layout engine on top of FreeType.  However, they are pretty   */
  /* handy for many other simple uses of the library.                      */
  /*                                                                       */
  /*************************************************************************/


#ifndef __FTGLYPH_H__
#define __FTGLYPH_H__


#include <ft2build.h>
#include FT_FREETYPE_H


FT_BEGIN_HEADER


  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    glyph_management                                                   */
  /*                                                                       */
  /* <Title>                                                               */
  /*    Glyph Management                                                   */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*    Generic interface to manage individual glyph data.                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This section contains definitions used to manage glyph data        */
  /*    through generic FT_Glyph objects.  Each of them can contain a      */
  /*    bitmap, a vector outline, or even images in other formats.         */
  /*                                                                       */
  /*************************************************************************/


  /* forward declaration to a private type */
  typedef struct FT_Glyph_Class_  FT_Glyph_Class;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FT_Glyph                                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Handle to an object used to model generic glyph images.  It is a   */
  /*    pointer to the @FT_GlyphRec structure and can contain a glyph      */
  /*    bitmap or pointer.                                                 */
  /*                                                                       */
  /* <Note>                                                                */
  /*    Glyph objects are not owned by the library.  You must thus release */
  /*    them manually (through @FT_Done_Glyph) _before_ calling            */
  /*    @FT_Done_FreeType.                                                 */
  /*                                                                       */
  typedef struct FT_GlyphRec_*  FT_Glyph;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FT_GlyphRec                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The root glyph structure contains a given glyph image plus its     */
  /*    advance width in 16.16 fixed float format.                         */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    library :: A handle to the FreeType library object.                */
  /*                                                                       */
  /*    clazz   :: A pointer to the glyph's class.  Private.               */
  /*                                                                       */
  /*    format  :: The format of the glyph's image.                        */
  /*                                                                       */
  /*    advance :: A 16.16 vector that gives the glyph's advance width.    */
  /*                                                                       */
  typedef struct  FT_GlyphRec_
  {
    FT_Library             library;
    const FT_Glyph_Class*  clazz;
    FT_Glyph_Format        format;
    FT_Vector              advance;

  } FT_GlyphRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FT_BitmapGlyph                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to an object used to model a bitmap glyph image.  This is */
  /*    a sub-class of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec.     */
  /*                                                                       */
  typedef struct FT_BitmapGlyphRec_*  FT_BitmapGlyph;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FT_BitmapGlyphRec                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used for bitmap glyph images.  This really is a        */
  /*    `sub-class' of `FT_GlyphRec'.                                      */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    root   :: The root FT_Glyph fields.                                */
  /*                                                                       */
  /*    left   :: The left-side bearing, i.e., the horizontal distance     */
  /*              from the current pen position to the left border of the  */
  /*              glyph bitmap.                                            */
  /*                                                                       */
  /*    top    :: The top-side bearing, i.e., the vertical distance from   */
  /*              the current pen position to the top border of the glyph  */
  /*              bitmap.  This distance is positive for upwards-y!        */
  /*                                                                       */
  /*    bitmap :: A descriptor for the bitmap.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    You can typecast FT_Glyph to FT_BitmapGlyph if you have            */
  /*    glyph->format == ft_glyph_format_bitmap.  This lets you access     */
  /*    the bitmap's contents easily.                                      */
  /*                                                                       */
  /*    The corresponding pixel buffer is always owned by the BitmapGlyph  */
  /*    and is thus created and destroyed with it.                         */
  /*                                                                       */
  typedef struct  FT_BitmapGlyphRec_
  {
    FT_GlyphRec  root;
    FT_Int       left;
    FT_Int       top;
    FT_Bitmap    bitmap;

  } FT_BitmapGlyphRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FT_OutlineGlyph                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to an object used to model an outline glyph image.  This  */
  /*    is a sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec. */
  /*                                                                       */
  typedef struct FT_OutlineGlyphRec_*  FT_OutlineGlyph;