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Posted 9 Nov 2010

FreeType on OpenGL ES (iPhone)

, 24 Nov 2010
Faster, smarter and better looking fonts rendered with OpenGL ES
OpenGLFont
.DS_Store
__MACOSX
OpenGLFont
._.DS_Store
arial.ttf
Classes
.DS_Store
Classes
._.DS_Store
EAGLView.mm
._EAGLView.mm
freetype-2.4.3
.DS_Store
freetype-2.4.3
._.DS_Store
.gitignore
include
.DS_Store
include
._.DS_Store
freetype
.DS_Store
freetype
._.DS_Store
config
config
internal
services
src
.DS_Store
src
._.DS_Store
OpenGLFontAppDelegate.mm
main.m
MainWindow.xib
OpenGLFont-Info.plist
._OpenGLFont-Info.plist
OpenGLFont.xcodeproj
lefty.mode1v3
lefty.pbxuser
project.pbxproj
OpenGLFont_Prefix.pch
Shaders
Shader.fsh
Shader.vsh
times.ttf
.DS_Store
arial.ttf
.DS_Store
EAGLView.mm
.DS_Store
.gitignore
.DS_Store
.DS_Store
.DS_Store
OpenGLFontAppDelegate.mm
main.m
MainWindow.xib
OpenGLFont-Info.plist
lefty.mode1v3
lefty.pbxuser
project.pbxproj
Shader.fsh
Shader.vsh
times.ttf
/***************************************************************************/
/*                                                                         */
/*  ftcache.h                                                              */
/*                                                                         */
/*    FreeType Cache subsystem (specification).                            */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010 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 __FTCACHE_H__
#define __FTCACHE_H__


#include <ft2build.h>
#include FT_GLYPH_H


FT_BEGIN_HEADER


  /*************************************************************************
   *
   * <Section>
   *    cache_subsystem
   *
   * <Title>
   *    Cache Sub-System
   *
   * <Abstract>
   *    How to cache face, size, and glyph data with FreeType~2.
   *
   * <Description>
   *   This section describes the FreeType~2 cache sub-system, which is used
   *   to limit the number of concurrently opened @FT_Face and @FT_Size
   *   objects, as well as caching information like character maps and glyph
   *   images while limiting their maximum memory usage.
   *
   *   Note that all types and functions begin with the `FTC_' prefix.
   *
   *   The cache is highly portable and thus doesn't know anything about the
   *   fonts installed on your system, or how to access them.  This implies
   *   the following scheme:
   *
   *   First, available or installed font faces are uniquely identified by
   *   @FTC_FaceID values, provided to the cache by the client.  Note that
   *   the cache only stores and compares these values, and doesn't try to
   *   interpret them in any way.
   *
   *   Second, the cache calls, only when needed, a client-provided function
   *   to convert an @FTC_FaceID into a new @FT_Face object.  The latter is
   *   then completely managed by the cache, including its termination
   *   through @FT_Done_Face.  To monitor termination of face objects, the
   *   finalizer callback in the `generic' field of the @FT_Face object can
   *   be used, which might also be used to store the @FTC_FaceID of the
   *   face.
   *
   *   Clients are free to map face IDs to anything else.  The most simple
   *   usage is to associate them to a (pathname,face_index) pair that is
   *   used to call @FT_New_Face.  However, more complex schemes are also
   *   possible.
   *
   *   Note that for the cache to work correctly, the face ID values must be
   *   *persistent*, which means that the contents they point to should not
   *   change at runtime, or that their value should not become invalid.
   *
   *   If this is unavoidable (e.g., when a font is uninstalled at runtime),
   *   you should call @FTC_Manager_RemoveFaceID as soon as possible, to let
   *   the cache get rid of any references to the old @FTC_FaceID it may
   *   keep internally.  Failure to do so will lead to incorrect behaviour
   *   or even crashes.
   *
   *   To use the cache, start with calling @FTC_Manager_New to create a new
   *   @FTC_Manager object, which models a single cache instance.  You can
   *   then look up @FT_Face and @FT_Size objects with
   *   @FTC_Manager_LookupFace and @FTC_Manager_LookupSize, respectively.
   *
   *   If you want to use the charmap caching, call @FTC_CMapCache_New, then
   *   later use @FTC_CMapCache_Lookup to perform the equivalent of
   *   @FT_Get_Char_Index, only much faster.
   *
   *   If you want to use the @FT_Glyph caching, call @FTC_ImageCache, then
   *   later use @FTC_ImageCache_Lookup to retrieve the corresponding
   *   @FT_Glyph objects from the cache.
   *
   *   If you need lots of small bitmaps, it is much more memory efficient
   *   to call @FTC_SBitCache_New followed by @FTC_SBitCache_Lookup.  This
   *   returns @FTC_SBitRec structures, which are used to store small
   *   bitmaps directly.  (A small bitmap is one whose metrics and
   *   dimensions all fit into 8-bit integers).
   *
   *   We hope to also provide a kerning cache in the near future.
   *
   *
   * <Order>
   *   FTC_Manager
   *   FTC_FaceID
   *   FTC_Face_Requester
   *
   *   FTC_Manager_New
   *   FTC_Manager_Reset
   *   FTC_Manager_Done
   *   FTC_Manager_LookupFace
   *   FTC_Manager_LookupSize
   *   FTC_Manager_RemoveFaceID
   *
   *   FTC_Node
   *   FTC_Node_Unref
   *
   *   FTC_ImageCache
   *   FTC_ImageCache_New
   *   FTC_ImageCache_Lookup
   *
   *   FTC_SBit
   *   FTC_SBitCache
   *   FTC_SBitCache_New
   *   FTC_SBitCache_Lookup
   *
   *   FTC_CMapCache
   *   FTC_CMapCache_New
   *   FTC_CMapCache_Lookup
   *
   *************************************************************************/


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                    BASIC TYPE DEFINITIONS                     *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /*************************************************************************
   *
   * @type: FTC_FaceID
   *
   * @description:
   *   An opaque pointer type that is used to identity face objects.  The
   *   contents of such objects is application-dependent.
   *
   *   These pointers are typically used to point to a user-defined
   *   structure containing a font file path, and face index.
   *
   * @note:
   *   Never use NULL as a valid @FTC_FaceID.
   *
   *   Face IDs are passed by the client to the cache manager, which calls,
   *   when needed, the @FTC_Face_Requester to translate them into new
   *   @FT_Face objects.
   *
   *   If the content of a given face ID changes at runtime, or if the value
   *   becomes invalid (e.g., when uninstalling a font), you should
   *   immediately call @FTC_Manager_RemoveFaceID before any other cache
   *   function.
   *
   *   Failure to do so will result in incorrect behaviour or even
   *   memory leaks and crashes.
   */
  typedef FT_Pointer  FTC_FaceID;


  /************************************************************************
   *
   * @functype:
   *   FTC_Face_Requester
   *
   * @description:
   *   A callback function provided by client applications.  It is used by
   *   the cache manager to translate a given @FTC_FaceID into a new valid
   *   @FT_Face object, on demand.
   *
   * <Input>
   *   face_id ::
   *     The face ID to resolve.
   *
   *   library ::
   *     A handle to a FreeType library object.
   *
   *   req_data ::
   *     Application-provided request data (see note below).
   *
   * <Output>
   *   aface ::
   *     A new @FT_Face handle.
   *
   * <Return>
   *   FreeType error code.  0~means success.
   *
   * <Note>
   *   The third parameter `req_data' is the same as the one passed by the
   *   client when @FTC_Manager_New is called.
   *
   *   The face requester should not perform funny things on the returned
   *   face object, like creating a new @FT_Size for it, or setting a
   *   transformation through @FT_Set_Transform!
   */
  typedef FT_Error
  (*FTC_Face_Requester)( FTC_FaceID  face_id,
                         FT_Library  library,
                         FT_Pointer  request_data,
                         FT_Face*    aface );

 /* */

#define FT_POINTER_TO_ULONG( p )  ( (FT_ULong)(FT_Pointer)(p) )

#define FTC_FACE_ID_HASH( i )                                \
          ((FT_UInt32)(( FT_POINTER_TO_ULONG( i ) >> 3 ) ^   \
                       ( FT_POINTER_TO_ULONG( i ) << 7 ) ) )


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                      CACHE MANAGER OBJECT                     *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_Manager                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This object corresponds to one instance of the cache-subsystem.    */
  /*    It is used to cache one or more @FT_Face objects, along with       */
  /*    corresponding @FT_Size objects.                                    */
  /*                                                                       */
  /*    The manager intentionally limits the total number of opened        */
  /*    @FT_Face and @FT_Size objects to control memory usage.  See the    */
  /*    `max_faces' and `max_sizes' parameters of @FTC_Manager_New.        */
  /*                                                                       */
  /*    The manager is also used to cache `nodes' of various types while   */
  /*    limiting their total memory usage.                                 */
  /*                                                                       */
  /*    All limitations are enforced by keeping lists of managed objects   */
  /*    in most-recently-used order, and flushing old nodes to make room   */
  /*    for new ones.                                                      */
  /*                                                                       */
  typedef struct FTC_ManagerRec_*  FTC_Manager;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_Node                                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    An opaque handle to a cache node object.  Each cache node is       */
  /*    reference-counted.  A node with a count of~0 might be flushed      */
  /*    out of a full cache whenever a lookup request is performed.        */
  /*                                                                       */
  /*    If you look up nodes, you have the ability to `acquire' them,      */
  /*    i.e., to increment their reference count.  This will prevent the   */
  /*    node from being flushed out of the cache until you explicitly      */
  /*    `release' it (see @FTC_Node_Unref).                                */
  /*                                                                       */
  /*    See also @FTC_SBitCache_Lookup and @FTC_ImageCache_Lookup.         */
  /*                                                                       */
  typedef struct FTC_NodeRec_*  FTC_Node;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_New                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Create a new cache manager.                                        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    library   :: The parent FreeType library handle to use.            */
  /*                                                                       */
  /*    max_faces :: Maximum number of opened @FT_Face objects managed by  */
  /*                 this cache instance.  Use~0 for defaults.             */
  /*                                                                       */
  /*    max_sizes :: Maximum number of opened @FT_Size objects managed by  */
  /*                 this cache instance.  Use~0 for defaults.             */
  /*                                                                       */
  /*    max_bytes :: Maximum number of bytes to use for cached data nodes. */
  /*                 Use~0 for defaults.  Note that this value does not    */
  /*                 account for managed @FT_Face and @FT_Size objects.    */
  /*                                                                       */
  /*    requester :: An application-provided callback used to translate    */
  /*                 face IDs into real @FT_Face objects.                  */
  /*                                                                       */
  /*    req_data  :: A generic pointer that is passed to the requester     */
  /*                 each time it is called (see @FTC_Face_Requester).     */
  /*                                                                       */
  /* <Output>                                                              */
  /*    amanager  :: A handle to a new manager object.  0~in case of       */
  /*                 failure.                                              */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_Manager_New( FT_Library          library,
                   FT_UInt             max_faces,
                   FT_UInt             max_sizes,
                   FT_ULong            max_bytes,
                   FTC_Face_Requester  requester,
                   FT_Pointer          req_data,
                   FTC_Manager        *amanager );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_Reset                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Empty a given cache manager.  This simply gets rid of all the      */
  /*    currently cached @FT_Face and @FT_Size objects within the manager. */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    manager :: A handle to the manager.                                */
  /*                                                                       */
  FT_EXPORT( void )
  FTC_Manager_Reset( FTC_Manager  manager );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_Done                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Destroy a given manager after emptying it.                         */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: A handle to the target cache manager object.            */
  /*                                                                       */
  FT_EXPORT( void )
  FTC_Manager_Done( FTC_Manager  manager );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_LookupFace                                             */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Retrieve the @FT_Face object that corresponds to a given face ID   */
  /*    through a cache manager.                                           */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: A handle to the cache manager.                          */
  /*                                                                       */
  /*    face_id :: The ID of the face object.                              */
  /*                                                                       */
  /* <Output>                                                              */
  /*    aface   :: A handle to the face object.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The returned @FT_Face object is always owned by the manager.  You  */
  /*    should never try to discard it yourself.                           */
  /*                                                                       */
  /*    The @FT_Face object doesn't necessarily have a current size object */
  /*    (i.e., face->size can be 0).  If you need a specific `font size',  */
  /*    use @FTC_Manager_LookupSize instead.                               */
  /*                                                                       */
  /*    Never change the face's transformation matrix (i.e., never call    */
  /*    the @FT_Set_Transform function) on a returned face!  If you need   */
  /*    to transform glyphs, do it yourself after glyph loading.           */
  /*                                                                       */
  /*    When you perform a lookup, out-of-memory errors are detected       */
  /*    _within_ the lookup and force incremental flushes of the cache     */
  /*    until enough memory is released for the lookup to succeed.         */
  /*                                                                       */
  /*    If a lookup fails with `FT_Err_Out_Of_Memory' the cache has        */
  /*    already been completely flushed, and still no memory was available */
  /*    for the operation.                                                 */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_Manager_LookupFace( FTC_Manager  manager,
                          FTC_FaceID   face_id,
                          FT_Face     *aface );


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FTC_ScalerRec                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used to describe a given character size in either      */
  /*    pixels or points to the cache manager.  See                        */
  /*    @FTC_Manager_LookupSize.                                           */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    face_id :: The source face ID.                                     */
  /*                                                                       */
  /*    width   :: The character width.                                    */
  /*                                                                       */
  /*    height  :: The character height.                                   */
  /*                                                                       */
  /*    pixel   :: A Boolean.  If 1, the `width' and `height' fields are   */
  /*               interpreted as integer pixel character sizes.           */
  /*               Otherwise, they are expressed as 1/64th of points.      */
  /*                                                                       */
  /*    x_res   :: Only used when `pixel' is value~0 to indicate the       */
  /*               horizontal resolution in dpi.                           */
  /*                                                                       */
  /*    y_res   :: Only used when `pixel' is value~0 to indicate the       */
  /*               vertical resolution in dpi.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    This type is mainly used to retrieve @FT_Size objects through the  */
  /*    cache manager.                                                     */
  /*                                                                       */
  typedef struct  FTC_ScalerRec_
  {
    FTC_FaceID  face_id;
    FT_UInt     width;
    FT_UInt     height;
    FT_Int      pixel;
    FT_UInt     x_res;
    FT_UInt     y_res;

  } FTC_ScalerRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FTC_Scaler                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to an @FTC_ScalerRec structure.                           */
  /*                                                                       */
  typedef struct FTC_ScalerRec_*  FTC_Scaler;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_LookupSize                                             */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Retrieve the @FT_Size object that corresponds to a given           */
  /*    @FTC_ScalerRec pointer through a cache manager.                    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: A handle to the cache manager.                          */
  /*                                                                       */
  /*    scaler  :: A scaler handle.                                        */
  /*                                                                       */
  /* <Output>                                                              */
  /*    asize   :: A handle to the size object.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The returned @FT_Size object is always owned by the manager.  You  */
  /*    should never try to discard it by yourself.                        */
  /*                                                                       */
  /*    You can access the parent @FT_Face object simply as `size->face'   */
  /*    if you need it.  Note that this object is also owned by the        */
  /*    manager.                                                           */
  /*                                                                       */
  /* <Note>                                                                */
  /*    When you perform a lookup, out-of-memory errors are detected       */
  /*    _within_ the lookup and force incremental flushes of the cache     */
  /*    until enough memory is released for the lookup to succeed.         */
  /*                                                                       */
  /*    If a lookup fails with `FT_Err_Out_Of_Memory' the cache has        */
  /*    already been completely flushed, and still no memory is available  */
  /*    for the operation.                                                 */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_Manager_LookupSize( FTC_Manager  manager,
                          FTC_Scaler   scaler,
                          FT_Size     *asize );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Node_Unref                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Decrement a cache node's internal reference count.  When the count */
  /*    reaches 0, it is not destroyed but becomes eligible for subsequent */
  /*    cache flushes.                                                     */
  /*                                                                       */
  /* <Input>                                                               */
  /*    node    :: The cache node handle.                                  */
  /*                                                                       */
  /*    manager :: The cache manager handle.                               */
  /*                                                                       */
  FT_EXPORT( void )
  FTC_Node_Unref( FTC_Node     node,
                  FTC_Manager  manager );


  /*************************************************************************
   *
   * @function:
   *   FTC_Manager_RemoveFaceID
   *
   * @description:
   *   A special function used to indicate to the cache manager that
   *   a given @FTC_FaceID is no longer valid, either because its
   *   content changed, or because it was deallocated or uninstalled.
   *
   * @input:
   *   manager ::
   *     The cache manager handle.
   *
   *   face_id ::
   *     The @FTC_FaceID to be removed.
   *
   * @note:
   *   This function flushes all nodes from the cache corresponding to this
   *   `face_id', with the exception of nodes with a non-null reference
   *   count.
   *
   *   Such nodes are however modified internally so as to never appear
   *   in later lookups with the same `face_id' value, and to be immediately
   *   destroyed when released by all their users.
   *
   */
  FT_EXPORT( void )
  FTC_Manager_RemoveFaceID( FTC_Manager  manager,
                            FTC_FaceID   face_id );


  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    cache_subsystem                                                    */
  /*                                                                       */
  /*************************************************************************/

  /*************************************************************************
   *
   * @type:
   *   FTC_CMapCache
   *
   * @description:
   *   An opaque handle used to model a charmap cache.  This cache is to
   *   hold character codes -> glyph indices mappings.
   *
   */
  typedef struct FTC_CMapCacheRec_*  FTC_CMapCache;


  /*************************************************************************
   *
   * @function:
   *   FTC_CMapCache_New
   *
   * @description:
   *   Create a new charmap cache.
   *
   * @input:
   *   manager ::
   *     A handle to the cache manager.
   *
   * @output:
   *   acache ::
   *     A new cache handle.  NULL in case of error.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   Like all other caches, this one will be destroyed with the cache
   *   manager.
   *
   */
  FT_EXPORT( FT_Error )
  FTC_CMapCache_New( FTC_Manager     manager,
                     FTC_CMapCache  *acache );


  /************************************************************************
   *
   * @function:
   *   FTC_CMapCache_Lookup
   *
   * @description:
   *   Translate a character code into a glyph index, using the charmap
   *   cache.
   *
   * @input:
   *   cache ::
   *     A charmap cache handle.
   *
   *   face_id ::
   *     The source face ID.
   *
   *   cmap_index ::
   *     The index of the charmap in the source face.  Any negative value
   *     means to use the cache @FT_Face's default charmap.
   *
   *   char_code ::
   *     The character code (in the corresponding charmap).
   *
   * @return:
   *    Glyph index.  0~means `no glyph'.
   *
   */
  FT_EXPORT( FT_UInt )
  FTC_CMapCache_Lookup( FTC_CMapCache  cache,
                        FTC_FaceID     face_id,
                        FT_Int         cmap_index,
                        FT_UInt32      char_code );


  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    cache_subsystem                                                    */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                       IMAGE CACHE OBJECT                      *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /*************************************************************************
   *
   * @struct:
   *   FTC_ImageTypeRec
   *
   * @description:
   *   A structure used to model the type of images in a glyph cache.
   *
   * @fields:
   *   face_id ::
   *     The face ID.
   *
   *   width ::
   *     The width in pixels.
   *
   *   height ::
   *     The height in pixels.
   *
   *   flags ::
   *     The load flags, as in @FT_Load_Glyph.
   *
   */
  typedef struct  FTC_ImageTypeRec_
  {
    FTC_FaceID  face_id;
    FT_Int      width;
    FT_Int      height;
    FT_Int32    flags;

  } FTC_ImageTypeRec;


  /*************************************************************************
   *
   * @type:
   *   FTC_ImageType
   *
   * @description:
   *   A handle to an @FTC_ImageTypeRec structure.
   *
   */
  typedef struct FTC_ImageTypeRec_*  FTC_ImageType;


  /* */


#define FTC_IMAGE_TYPE_COMPARE( d1, d2 )      \
          ( (d1)->face_id == (d2)->face_id && \
            (d1)->width   == (d2)->width   && \
            (d1)->flags   == (d2)->flags   )

#define FTC_IMAGE_TYPE_HASH( d )                          \
          (FT_UFast)( FTC_FACE_ID_HASH( (d)->face_id )  ^ \
                      ( (d)->width << 8 ) ^ (d)->height ^ \
                      ( (d)->flags << 4 )               )


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_ImageCache                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to an glyph image cache object.  They are designed to     */
  /*    hold many distinct glyph images while not exceeding a certain      */
  /*    memory threshold.                                                  */
  /*                                                                       */
  typedef struct FTC_ImageCacheRec_*  FTC_ImageCache;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_ImageCache_New                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Create a new glyph image cache.                                    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: The parent manager for the image cache.                 */
  /*                                                                       */
  /* <Output>                                                              */
  /*    acache  :: A handle to the new glyph image cache object.           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_ImageCache_New( FTC_Manager      manager,
                      FTC_ImageCache  *acache );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_ImageCache_Lookup                                              */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Retrieve a given glyph image from a glyph image cache.             */
  /*                                                                       */
  /* <Input>                                                               */
  /*    cache  :: A handle to the source glyph image cache.                */
  /*                                                                       */
  /*    type   :: A pointer to a glyph image type descriptor.              */
  /*                                                                       */
  /*    gindex :: The glyph index to retrieve.                             */
  /*                                                                       */
  /* <Output>                                                              */
  /*    aglyph :: The corresponding @FT_Glyph object.  0~in case of        */
  /*              failure.                                                 */
  /*                                                                       */
  /*    anode  :: Used to return the address of of the corresponding cache */
  /*              node after incrementing its reference count (see note    */
  /*              below).                                                  */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The returned glyph is owned and managed by the glyph image cache.  */
  /*    Never try to transform or discard it manually!  You can however    */
  /*    create a copy with @FT_Glyph_Copy and modify the new one.          */
  /*                                                                       */
  /*    If `anode' is _not_ NULL, it receives the address of the cache     */
  /*    node containing the glyph image, after increasing its reference    */
  /*    count.  This ensures that the node (as well as the @FT_Glyph) will */
  /*    always be kept in the cache until you call @FTC_Node_Unref to      */
  /*    `release' it.                                                      */
  /*                                                                       */
  /*    If `anode' is NULL, the cache node is left unchanged, which means  */
  /*    that the @FT_Glyph could be flushed out of the cache on the next   */
  /*    call to one of the caching sub-system APIs.  Don't assume that it  */
  /*    is persistent!                                                     */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_ImageCache_Lookup( FTC_ImageCache  cache,
                         FTC_ImageType   type,
                         FT_UInt         gindex,
                         FT_Glyph       *aglyph,
                         FTC_Node       *anode );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_ImageCache_LookupScaler                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A variant of @FTC_ImageCache_Lookup that uses an @FTC_ScalerRec    */
  /*    to specify the face ID and its size.                               */
  /*                                                                       */
  /* <Input>                                                               */
  /*    cache      :: A handle to the source glyph image cache.            */
  /*                                                                       */
  /*    scaler     :: A pointer to a scaler descriptor.                    */
  /*                                                                       */
  /*    load_flags :: The corresponding load flags.                        */
  /*                                                                       */
  /*    gindex     :: The glyph index to retrieve.                         */
  /*                                                                       */
  /* <Output>                                                              */
  /*    aglyph     :: The corresponding @FT_Glyph object.  0~in case of    */
  /*                  failure.                                             */
  /*                                                                       */
  /*    anode      :: Used to return the address of of the corresponding   */
  /*                  cache node after incrementing its reference count    */
  /*                  (see note below).                                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The returned glyph is owned and managed by the glyph image cache.  */
  /*    Never try to transform or discard it manually!  You can however    */
  /*    create a copy with @FT_Glyph_Copy and modify the new one.          */
  /*                                                                       */
  /*    If `anode' is _not_ NULL, it receives the address of the cache     */
  /*    node containing the glyph image, after increasing its reference    */
  /*    count.  This ensures that the node (as well as the @FT_Glyph) will */
  /*    always be kept in the cache until you call @FTC_Node_Unref to      */
  /*    `release' it.                                                      */
  /*                                                                       */
  /*    If `anode' is NULL, the cache node is left unchanged, which means  */
  /*    that the @FT_Glyph could be flushed out of the cache on the next   */
  /*    call to one of the caching sub-system APIs.  Don't assume that it  */
  /*    is persistent!                                                     */
  /*                                                                       */
  /*    Calls to @FT_Set_Char_Size and friends have no effect on cached    */
  /*    glyphs; you should always use the FreeType cache API instead.      */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_ImageCache_LookupScaler( FTC_ImageCache  cache,
                               FTC_Scaler      scaler,
                               FT_ULong        load_flags,
                               FT_UInt         gindex,
                               FT_Glyph       *aglyph,
                               FTC_Node       *anode );


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_SBit                                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to a small bitmap descriptor.  See the @FTC_SBitRec       */
  /*    structure for details.                                             */
  /*                                                                       */
  typedef struct FTC_SBitRec_*  FTC_SBit;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FTC_SBitRec                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A very compact structure used to describe a small glyph bitmap.    */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    width     :: The bitmap width in pixels.                           */
  /*                                                                       */
  /*    height    :: The bitmap height in pixels.                          */
  /*                                                                       */
  /*    left      :: The horizontal distance from the pen position to the  */
  /*                 left bitmap border (a.k.a. `left side bearing', or    */
  /*                 `lsb').                                               */
  /*                                                                       */
  /*    top       :: The vertical distance from the pen position (on the   */
  /*                 baseline) to the upper bitmap border (a.k.a. `top     */
  /*                 side bearing').  The distance is positive for upwards */
  /*                 y~coordinates.                                        */
  /*                                                                       */
  /*    format    :: The format of the glyph bitmap (monochrome or gray).  */
  /*                                                                       */
  /*    max_grays :: Maximum gray level value (in the range 1 to~255).     */
  /*                                                                       */
  /*    pitch     :: The number of bytes per bitmap line.  May be positive */
  /*                 or negative.                                          */
  /*                                                                       */
  /*    xadvance  :: The horizontal advance width in pixels.               */
  /*                                                                       */
  /*    yadvance  :: The vertical advance height in pixels.                */
  /*                                                                       */
  /*    buffer    :: A pointer to the bitmap pixels.                       */
  /*                                                                       */
  typedef struct  FTC_SBitRec_
  {
    FT_Byte   width;
    FT_Byte   height;
    FT_Char   left;
    FT_Char   top;

    FT_Byte   format;
    FT_Byte   max_grays;
    FT_Short  pitch;
    FT_Char   xadvance;
    FT_Char   yadvance;

    FT_Byte*  buffer;

  } FTC_SBitRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_SBitCache                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to a small bitmap cache.  These are special cache objects */
  /*    used to store small glyph bitmaps (and anti-aliased pixmaps) in a  */
  /*    much more efficient way than the traditional glyph image cache     */
  /*    implemented by @FTC_ImageCache.                                    */
  /*                                                                       */
  typedef struct FTC_SBitCacheRec_*  FTC_SBitCache;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_SBitCache_New                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Create a new cache to store small glyph bitmaps.                   */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: A handle to the source cache manager.                   */
  /*                                                                       */
  /* <Output>                                                              */
  /*    acache  :: A handle to the new sbit cache.  NULL in case of error. */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_SBitCache_New( FTC_Manager     manager,
                     FTC_SBitCache  *acache );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_SBitCache_Lookup                                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Look up a given small glyph bitmap in a given sbit cache and       */
  /*    `lock' it to prevent its flushing from the cache until needed.     */
  /*                                                                       */
  /* <Input>                                                               */
  /*    cache  :: A handle to the source sbit cache.                       */
  /*                                                                       */
  /*    type   :: A pointer to the glyph image type descriptor.            */
  /*                                                                       */
  /*    gindex :: The glyph index.                                         */
  /*                                                                       */
  /* <Output>                                                              */
  /*    sbit   :: A handle to a small bitmap descriptor.                   */
  /*                                                                       */
  /*    anode  :: Used to return the address of of the corresponding cache */
  /*              node after incrementing its reference count (see note    */
  /*              below).                                                  */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The small bitmap descriptor and its bit buffer are owned by the    */
  /*    cache and should never be freed by the application.  They might    */
  /*    as well disappear from memory on the next cache lookup, so don't   */
  /*    treat them as persistent data.                                     */
  /*                                                                       */
  /*    The descriptor's `buffer' field is set to~0 to indicate a missing  */
  /*    glyph bitmap.                                                      */
  /*                                                                       */
  /*    If `anode' is _not_ NULL, it receives the address of the cache     */
  /*    node containing the bitmap, after increasing its reference count.  */
  /*    This ensures that the node (as well as the image) will always be   */
  /*    kept in the cache until you call @FTC_Node_Unref to `release' it.  */
  /*                                                                       */
  /*    If `anode' is NULL, the cache node is left unchanged, which means  */
  /*    that the bitmap could be flushed out of the cache on the next      */
  /*    call to one of the caching sub-system APIs.  Don't assume that it  */
  /*    is persistent!                                                     */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_SBitCache_Lookup( FTC_SBitCache    cache,
                        FTC_ImageType    type,
                        FT_UInt          gindex,
                        FTC_SBit        *sbit,
                        FTC_Node        *anode );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_SBitCache_LookupScaler                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A variant of @FTC_SBitCache_Lookup that uses an @FTC_ScalerRec     */
  /*    to specify the face ID and its size.                               */
  /*                                                                       */
  /* <Input>                                                               */
  /*    cache      :: A handle to the source sbit cache.                   */
  /*                                                                       */
  /*    scaler     :: A pointer to the scaler descriptor.                  */
  /*                                                                       */
  /*    load_flags :: The corresponding load flags.                        */
  /*                                                                       */
  /*    gindex     :: The glyph index.                                     */
  /*                                                                       */
  /* <Output>                                                              */
  /*    sbit       :: A handle to a small bitmap descriptor.               */
  /*                                                                       */
  /*    anode      :: Used to return the address of of the corresponding   */
  /*                  cache node after incrementing its reference count    */
  /*                  (see note below).                                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0~means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The small bitmap descriptor and its bit buffer are owned by the    */
  /*    cache and should never be freed by the application.  They might    */
  /*    as well disappear from memory on the next cache lookup, so don't   */
  /*    treat them as persistent data.                                     */
  /*                                                                       */
  /*    The descriptor's `buffer' field is set to~0 to indicate a missing  */
  /*    glyph bitmap.                                                      */
  /*                                                                       */
  /*    If `anode' is _not_ NULL, it receives the address of the cache     */
  /*    node containing the bitmap, after increasing its reference count.  */
  /*    This ensures that the node (as well as the image) will always be   */
  /*    kept in the cache until you call @FTC_Node_Unref to `release' it.  */
  /*                                                                       */
  /*    If `anode' is NULL, the cache node is left unchanged, which means  */
  /*    that the bitmap could be flushed out of the cache on the next      */
  /*    call to one of the caching sub-system APIs.  Don't assume that it  */
  /*    is persistent!                                                     */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_SBitCache_LookupScaler( FTC_SBitCache  cache,
                              FTC_Scaler     scaler,
                              FT_ULong       load_flags,
                              FT_UInt        gindex,
                              FTC_SBit      *sbit,
                              FTC_Node      *anode );


 /* */

#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

  /*@***********************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FTC_FontRec                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A simple structure used to describe a given `font' to the cache    */
  /*    manager.  Note that a `font' is the combination of a given face    */
  /*    with a given character size.                                       */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    face_id    :: The ID of the face to use.                           */
  /*                                                                       */
  /*    pix_width  :: The character width in integer pixels.               */
  /*                                                                       */
  /*    pix_height :: The character height in integer pixels.              */
  /*                                                                       */
  typedef struct  FTC_FontRec_
  {
    FTC_FaceID  face_id;
    FT_UShort   pix_width;
    FT_UShort   pix_height;

  } FTC_FontRec;


  /* */


#define FTC_FONT_COMPARE( f1, f2 )                  \
          ( (f1)->face_id    == (f2)->face_id    && \
            (f1)->pix_width  == (f2)->pix_width  && \
            (f1)->pix_height == (f2)->pix_height )

#define FTC_FONT_HASH( f )                              \
          (FT_UInt32)( FTC_FACE_ID_HASH((f)->face_id) ^ \
                       ((f)->pix_width << 8)          ^ \
                       ((f)->pix_height)              )

  typedef FTC_FontRec*  FTC_Font;


  FT_EXPORT( FT_Error )
  FTC_Manager_Lookup_Face( FTC_Manager  manager,
                           FTC_FaceID   face_id,
                           FT_Face     *aface );

  FT_EXPORT( FT_Error )
  FTC_Manager_Lookup_Size( FTC_Manager  manager,
                           FTC_Font     font,
                           FT_Face     *aface,
                           FT_Size     *asize );

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */


 /* */

FT_END_HEADER

#endif /* __FTCACHE_H__ */


/* END */

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About the Author

ed welch
Software Developer Astronautz
Spain Spain
After working in the software industry for many years, I've started my own games company that specialises in strategy games for mobile platforms.

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Web01 | 2.8.170915.1 | Last Updated 24 Nov 2010
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