ftifi.c

字体缩放显示

/*                                                                         */
/*             OS/2 Font Driver using the FreeType library                 */
/*                                                                         */
/*       Copyright (C) 1997, 1998 Michal Necasek <[e-mail]>         */
/*       Copyright (C) 1997, 1998 David Turner <[e-mail]>      */
/*       Copyright (C) 1997, 1998 International Business Machines          */
/*                                                                         */
/*       Version: 0.9.90 (Beta)                                            */
/*                                                                         */
/* This source is to be compiled with IBM VisualAge C++ 3.0 or possibly    */
/* Watcom C/C++ 10.0 or higher (Wactom doesn't quite work yet).            */
/* Other compilers may actually work too but don't forget this is NOT a    */
/* normal DLL but rather a subsystem DLL. That means it shouldn't use      */
/* the usual C library as it has to run without runtime environment.       */
/* VisualAge provides a special subsystem version of the run-time library. */
/* All this is of course very compiler-dependent. See makefiles for        */
/* discussion of switches used.                                            */
/*                                                                         */
/*  Implemantation Notes:                                                  */
/*                                                                         */
/* Note #1: As a consequence of this being a subsystem librarary, I had to */
/*   slightly modify the FreeType source, namely ttmemory.c and ttfile.c.  */
/*   FreeType/2 now allocates several chunks of memory and uses them as a  */
/*   heap. Note that memory allocation should use TTAlloc(), possibly      */
/*   directly SSAllocMem(). malloc() is unusable here and it doesn't work  */
/*   at all (runtime library isn't even initialized). See ttmemory.c for   */
/*   more info.                                                            */
/*    In ttfile.c I had to change all fopen(), fseek()... calls            */
/*   to OS/2 API calls (DosOpen, DosSetFilePtr...) because without proper  */
/*   runtime environment a subsystem DLL cannot use std C library calls.   */
/*                                                                         */
/* Note #2: On exit of each function reading from font file the API        */
/*   TT_Flush_Stream() must be called. This is because file handles opened */
/*   by this DLL actually belong to the calling process. As a consequence  */
/*    a) it's easy to run out of file handles, which results in really     */
/*       very nasty behavior and/or crashes. This could be solved by       */
/*       increased file handles limit, but cannot because                  */
/*    b) it is impossible to close files open by another process and       */
/*       therefore the fonts cannot be properly uninstalled (you can't     */
/*       delete them while the're open by other process)                   */
/*   The only solution I found is very simple - just close the file before */
/*   exiting a DLL function. This ensures files are not left open across   */
/*   processes and other problems.                                         */
/*                                                                         */
/* Note #3: The whole business with linked lists is aimed at lowering      */
/*   memory consumption drastically. If you install 50 TT fonts, OS/2      */
/*   opens all of them at startup. Even if you never use them, they take   */
/*   up at least over 1 Meg memory. With certain fonts the consumption can */
/*   easily go over several MB. We limit such waste of memory by only      */
/*   actually keeping open several typefaces most recently used. Their     */
/*   number can be set via entry in OS2.INI.                               */
/*                                                                         */
/* For Intelligent Font Interface (IFI) specification please see IFI32.TXT */

#ifndef  __IBMC__
   #ifndef __WATCOMC__
      #error "This source requires IBM VisualAge C++ or Watcom C/C++"
   #endif
#endif

/* Defining the following uses UCONV.DLL instead of the built-in  */
/* translation tables. This code should work on any Warp 4 and    */
/* Warp 3 w/ FixPak 35(?) and above                               */
/* Note: this should be defined before FTIFI.H is #included       */
#undef  USE_UCONV

#define INCL_WINSHELLDATA   /* for accessing OS2.INI */
#define INCL_DOSMISC
#define INCL_DOSNLS
#define INCL_DOSPROCESS
#define INCL_GRE_DCS
#define INCL_GRE_DEVSUPPORT
#define INCL_DDIMISC
#define INCL_IFI
#include <os2.h>
#include <pmddi.h>     /* SSAllocmem(), SSFreemem() and more */

#ifdef USE_UCONV       /* uconv.h isn't always available */
#include <uconv.h>
#endif  /* USE_UCONV */

#include <string.h>
#include <stdlib.h>         /* min and max macros */

#define  _syscall  _System  /* the IFI headers don't compile without it */

#include "32pmifi.h"        /* IFI header             */
#include "freetype.h"       /* FreeType header        */
#include "ftxkern.h"        /* kerning extension      */
#include "ftxwidth.h"       /* glyph width extension  */
#include "ftifi.h"          /* xlate table            */


/* For the sake of Netscape's text rendering bugs ! */
#define NETSCAPE_FIX

/* Create 'fake' Roman face for Times New Roman (to mimic PMATM's */
/* behaviour                                                      */
#define FAKE_TNR

/* (indirectly) exported functions */
LONG _System ConvertFontFile(PSZ pszSrc, PSZ pszDestDir, PSZ pszNewName);
HFF  _System LoadFontFile(PSZ pszFileName);
LONG _System UnloadFontFile(HFF hff);
LONG _System QueryFaces(HFF hff, PIFIMETRICS pifiMetrics, ULONG cMetricLen,
                        ULONG cFountCount, ULONG cStart);
HFC  _System OpenFontContext(HFF hff, ULONG ulFont);
LONG _System SetFontContext(HFC hfc, PCONTEXTINFO pci);
LONG _System CloseFontContext(HFC hfc);
LONG _System QueryFaceAttr(HFC hfc, ULONG iQuery, PBYTE pBuffer,
                           ULONG cb, PGLYPH pagi, GLYPH giStart);
LONG _System QueryCharAttr(HFC hfc, PCHARATTR pCharAttr,
                           PBITMAPMETRICS pbmm);
LONG _System QueryFullFaces(HFF hff, PVOID pBuff, PULONG buflen,
                            PULONG cFontCount, ULONG cStart);

FDDISPATCH fdisp = {        /* Font driver dispatch table */
   LoadFontFile,
   QueryFaces,
   UnloadFontFile,
   OpenFontContext,
   SetFontContext,
   CloseFontContext,
   QueryFaceAttr,
   QueryCharAttr,
   NULL,     /* this one is no more used, only the spec fails to mention it */
   ConvertFontFile,
   QueryFullFaces
};



/****************************************************************************/
/* the single exported entry point; this way is faster than exporting every */
/* single function and a bit more flexible                                  */
/*                                                                          */
#pragma export (fdhdr, "FONT_DRIVER_DISPATCH_TABLE", 1)
FDHEADER   fdhdr =
{  /* Font driver Header */
   sizeof(FDHEADER),
   "OS/2 FONT DRIVER",                  /* do not change */
   "TrueType (Using FreeType Engine)",  /* description up to 40 chars */
   IFI_VERSION20,                       /* version */
   0,                                   /* reserved */
   &fdisp
};


/****************************************************************************/
/* some debug macros and functions. the debug version logs system requests  */
/* to the file C:\FTIFI.LOG                                                 */
/*                                                                          */
#ifdef DEBUG
  HFILE LogHandle = NULLHANDLE;
  ULONG Written   = 0;
  char  log[2048] = "";
  char  buf[2048] = "";


char*  itoa10( int i, char* buffer ) {
    char*  ptr  = buffer;
    char*  rptr = buffer;
    char   digit;

    if (i == 0) {
      buffer[0] = '0';
      buffer[1] =  0;
      return buffer;
    }

    if (i < 0) {
      *ptr = '-';
       ptr++; rptr++;
       i   = -i;
    }

    while (i != 0) {
      *ptr = (char) (i % 10 + '0');
       ptr++;
       i  /= 10;
    }

    *ptr = 0;  ptr--;

    while (ptr > rptr) {
      digit = *ptr;
      *ptr  = *rptr;
      *rptr = digit;
       ptr--;
       rptr++;
    }

    return buffer;
}

  #define  COPY(s)     strcpy(log, s)
  #define  CAT(s)      strcat(log, s)
  #define  CATI(v)     strcat(log, itoa10( (int)v, buf ))
  #define  WRITE       DosWrite(LogHandle, log, strlen(log), &Written)

  #define  ERET1(label) { COPY("Error at ");  \
                          CATI(__LINE__);    \
                          CAT("\r\n");       \
                          WRITE;             \
                          goto label;        \
                       }

  #define  ERRRET(e)   { COPY("Error at ");  \
                          CATI(__LINE__);    \
                          CAT("\r\n");       \
                          WRITE;             \
                          return(e);         \
                       }


#else

  #define  COPY(s)
  #define  CAT(s)
  #define  CATI(v)
  #define  WRITE

  #define  ERET1(label)  goto label;

  #define  ERRRET(e)  return(e);

#endif /* DEBUG */


/****************************************************************************/
/*                                                                          */
/* 'engine' :                                                               */
/*                                                                          */
/*  The FreeType engine instance. Although this is a DLL, it isn't          */
/*  supposed to be shared by apps, as it is only called by the OS/2 GRE.    */
/*  This means that there is no need to bother with reentrancy/thread       */
/*  safety, which aren't supported by FreeType 1.0 anyway.                  */
/*                                                                          */
TT_Engine engine;

/****************************************************************************/
/*                                                                          */
/* TList and TListElement :                                                 */
/*                                                                          */
/*  simple structures used to implement a doubly linked list. Lists are     */
/*  used to implement the HFF object lists, as well as the font size and    */
/*  outline caches.                                                         */
/*                                                                          */

typedef struct _TListElement  TListElement, *PListElement;

struct _TListElement
{
  PListElement  next;    /* next element in list - NULL if tail     */
  PListElement  prev;    /* previous element in list - NULL if head */
  long          key;     /* value used for searches                 */
  void*         data;    /* pointer to the listed/cached object     */
};

typedef struct _TList  TList, *PList;
struct _TList
{
  PListElement  head;    /* first element in list - NULL if empty */
  PListElement  tail;    /* last element in list - NULL if empty  */
  int           count;   /* number of elements in list            */
};

static  PListElement  free_elements = 0;

#if 0
/****************************************************************************/
/*                                                                          */
/* TGlyph_Image :                                                           */
/*                                                                          */
/*  structure used to store a glyph's attributes, i.e. outlines and metrics */
/*  Note that we do not cache bitmaps ourselves for the moment.             */
/*                                                                          */
typedef struct _TGlyph_Image  TGlyph_Image,  *PGlyph_Image;

struct _TGlyph_Image
{
  PListElement      element;  /* list element for this glyph image */
  TT_Glyph_Metrics  metrics;
  TT_Outline        outline;
};
#endif


/****************************************************************************/
/*                                                                          */
/* TFontFace :                                                              */
/*                                                                          */
/* a structure related to an open font face. It contains data for each of   */
/* possibly several faces in a .TTC file.                                   */

typedef struct _TFontFace  TFontFace, *PFontFace;

struct _TFontFace
{
   TT_Face       face;            /* handle to actual FreeType face object  */
   TT_Glyph      glyph;           /* handle to FreeType glyph container     */
   TT_CharMap    charMap;         /* handle to FreeType character map       */
   TT_Kerning    directory;       /* kerning directory                      */
   USHORT        *widths;         /* glyph width cache for large fonts      */
   USHORT        *kernIndices;    /* reverse translation cache for kerning  */
   LONG          em_size;         /* points per em square                   */
   ULONG         flags;           /* various FC_* flags (like FC_FLAG_FIXED)*/
#if 0   /* not now */
   TList         sizes;           /* list of live child font sizes          */
#endif
   LONG          charMode;        /* character translation mode :           */
                                  /*   0 = Unicode to UGL                   */
                                  /*   1 = Symbol (no translation)          */
                                  /*   2 = Unicode w/o translation          */
};


/****************************************************************************/
/*                                                                          */
/* TFontFile :                                                              */
/*                                                                          */
/* a structure related to an open font file handle. All TFontFiles are      */
/* kept in a simple linked list. There can be several faces in one font.    */
/* Face(s) information is stored in a variable-length array of TFontFaces.  */
/* A single TFontFile structure exactly corresponds to one HFF.             */

typedef struct _TFontFile  TFontFile, *PFontFile;

struct _TFontFile
{
   PListElement  element;         /* list element for this font face        */
   HFF           hff;             /* HFF handle used from outside           */
   CHAR          filename[260];   /* font file name                         */
   LONG          ref_count;       /* number of times this font file is open */
   ULONG         flags;           /* various FL_* flags                     */
   ULONG         numFaces;        /* number of faces in a file (normally 1) */
   TFontFace     *faces;          /* array of FontFace structures           */