/* fontreader.c - functions for reading PK fonts
   $Id: fontreader.c,v 0.2 1997/03/28 03:16:59 tjchol01 Exp $
   Authors: Andrew Trevorrow, Ian Dall, Geoffrey Tobin, Tomasz J. Cholewo
 */

#include "dvgt.h"
#include <kpathsea/tex-file.h>
#include <kpathsea/tex-glyph.h>

#include "screenio.h"
#include "vdu.h"
#include "options.h"
#include "dvireader.h"
#include "fontreader.h"

typedef struct _REC_TFMinfo
  {
    int wdindex, htindex, dpindex;
  }
_REC_TFMinfo;

typedef struct _REC_charmetrics
  {
    int width[4], height[4], depth[4];
  }
_REC_charmetrics;


static int PTfile;		/* PK/TFM file descriptor              */
static int PToffset;		/* current byte offset in PTfile       */
static int currPTbuff;		/* starting byte offset in buffer      */
static buffer PTbuffer;		/* input buffer                        */
static int gpower[33];		/* 0,1,11,111,1111,...                 */
static boolean turnon;		/* is current run black?               */
static int dynf;		/* dynamic packing variable            */
static int repeatcount;		/* times to repeat the next row        */
static int bitweight;		/* for bits or nybbles from inputbyte  */
static int inputbyte;		/* the current input byte              */
static int lf, lh, bc, ec, nw, nh;	/* TFM file data; lf unused  */
static _REC_TFMinfo TFMinfo[maxTeXchar + 1];
static _REC_charmetrics charmetrics[maxTeXchar + 1];

/*--------------------------------------------------------------------*/
boolean 
CheckFontPtr (fontinfo * fontptr)
{
  boolean check = false;
  if (fontptr == (fontinfo *) NULL)
    {
      MesgString ("NULL font info passed to CheckFontPtr!");
      MesgLine ();
      check = false;
    }
  else if (fontptr->fontnamelen == 0)
    {
      MesgString ("Zero length font name in font info passed to CheckFontPtr!");
      MesgLine ();
      check = false;
    }
  else if (!strcmp (fontptr->fontname, ""))
    {
      MesgString ("Empty font name in font info passed to CheckFontPtr!");
      MesgLine ();
      check = false;
    }
  else
    {
      check = true;
    }
  return check;
}
/* CheckFontPtr */

/*--------------------------------------------------------------------*/

boolean 
BuildFontSpec (fontinfo * fontptr)
{
  /* Build a complete PK or TFM font file specification in fontptr->fontspec.
     (May end up with a dummy PK font's or TFM metric's file spec.
     ShowStatistics() in "dvitovdu.c" will show any font substitutions.)
     This will be done at most once per font.
     Test for valid fontptr->fontname.
     ASSUMPTIONS:
     fontptr->fontname contains the basename of the font.
     SIDE EFFECTS on success:
     fontptr->fontspec will be set.
     fontptr->fontspeclen will no longer be 0.
     fontptr->fontexists becomes TRUE if the real or dummy PK or TFM
     file can be opened, FALSE, otherwise.
     fontptr->pkfont becomes TRUE if the real or dummy PK file
     can be opened, FALSE, otherwise.
     fontptr->honest becomes TRUE if the true font is used, FALSE otherwise.
     SIDE EFFECTS on failure:
     EITHER:
     fontptr is NULL.
     OR:
     fontptr->fontspec will be unset (holds empty string "").
     fontptr->fontspeclen will be 0.
     fontptr->fontexists becomes FALSE.
     fontptr->pkfont becomes FALSE.
     fontptr->honest becomes FALSE.
   */

  kpse_glyph_file_type font_ret;
  string name;
  unsigned dpi;

  if (!CheckFontPtr (fontptr))
    return false;

  /* Initialise correctly */
  strncpy (fontptr->fontspec, "", maxfontspec);
  fontptr->fontspeclen = 0;
  fontptr->fontexists = false;
  fontptr->pkfont = false;
  fontptr->honest = false;

#if 0
  dpi = kpse_magstep_fix ((unsigned) (mag / 5.0 + .5),
			  xres, NULL);
  tfontptr->font_mag = dpi * 5;	/* save correct dpi */
#endif
  dpi = (int) (mag / 1000.0 *
	   (double) fontptr->scaledsize / fontptr->designsize * xres + 0.5);

  if (dpi == 0)			/* allow for subtracting 1 */
    ++dpi;

  name = kpse_find_pk (fontptr->fontname, dpi, &font_ret);
  if (name)
    {
      if (!STREQ (fontptr->fontname, font_ret.name))
	{
#if 0
	  WARNING3 ("dvgt: Font %s not found, using %s at %d instead.\n",
		    fontptr->fontname, font_ret.name, font_ret.dpi);
#endif
	}
      else if (!kpse_bitmap_tolerance ((double) font_ret.dpi, (double) dpi))
	{
#if 0
	  WARNING3 ("dvilj: Font %s at %d not found, using %d instead.\n",
		    fontptr->fontname, dpi, font_ret.dpi);
#endif
	}
      else
	fontptr->honest = true;

      fontptr->fontspeclen = strlen (name);
      strcpy (fontptr->fontspec, name);
      free (name);
      fontptr->fontexists = true;	/* specified PK file exists */
      fontptr->pkfont = true;

      return true;
    }
  else
    {
      /* PK font file doesn't exist. */
      name = kpse_find_tfm (fontptr->fontname);
      if (name)
	{
	  fontptr->fontspeclen = strlen (name);
	  strcpy (fontptr->fontspec, name);
	  free (name);

	  fontptr->fontexists = true;
	  fontptr->honest = true;
	}
      else
	{
	  name = kpse_find_tfm (dummy_tfm);
	  if (name)
	    {
	      fontptr->fontspeclen = strlen (name);
	      strcpy (fontptr->fontspec, name);
	      free (name);
	      fontptr->fontexists = true;
	    }
	}
    }

  return true;
}
/* BuildFontSpec */

/*--------------------------------------------------------------------*/

boolean 
OpenFontFile (char *name)
{
  /* Return TRUE if given file can be (unix-specifically) open-ed.
     Only one font file will be open at any given time.
   */

  extern int currPTbuff;
  extern int PTfile;

  currPTbuff = -1;		/* impossible value for first GetPTByte */
  PTfile = open (name, O_RDONLY, 0);	/* unix "open" returns -1 if fails */
  return (PTfile >= 0);
}
/* OpenFontFile */

/*--------------------------------------------------------------------*/

void
CloseFontFile ()
{
  /* If there is a currently open font file, then close it. */

  if (PTfile >= 0)
    {
      close (PTfile);
      /* Be cautious:  ensure PTfile is negative, after this function. */
      if (PTfile >= 0)
	PTfile = -1;
    }
}
/* CloseFontFile */

/*--------------------------------------------------------------------*/

static int
GetPTByte ()
{
  /* Returns the value (unsigned) of the byte at PToffset and
     advances PToffset for the next GetPTByte.
   */

  int Result, buffstart, result;

  buffstart = PToffset / bufflen * bufflen;	/* 0, bufflen, 2*bufflen... */
  if (buffstart != currPTbuff)
    {
      currPTbuff = buffstart;

      if (PTfile < 0)
	{
	  StartText ();
	  ResetVDU ();		/* let message stay */

	  FATAL ("PTfile not open in GetPTByte!");
	}
      result = lseek (PTfile, buffstart, 0);
      if (result != buffstart)
	{
	  StartText ();
	  ResetVDU ();		/* let message stay */

	  FATAL ("lseek failed in GetPTByte!");
	}
      result = read (PTfile, PTbuffer, bufflen);
      if (result == -1)
	{
	  StartText ();
	  ResetVDU ();		/* let message stay */

	  FATAL ("Read failed in GetPTByte!");
	}
    }
  Result = PTbuffer[PToffset - buffstart];
  PToffset++;
  return Result;
}
/* GetPTByte */

/*--------------------------------------------------------------------*/

static int
SignedPTByte ()
{
  /* the next byte, signed */
  int b;

  b = GetPTByte ();
  if (b < 128)
    return b;
  else
    return (b - 256);
}
/* SignedPTByte */

/*--------------------------------------------------------------------*/

static int
GetTwoPTBytes ()
{
  /* the next 2 bytes, unsigned */
  int a, b;

  a = GetPTByte ();
  b = GetPTByte ();
  return (a * 256 + b);
}
/* GetTwoPTBytes */

/*--------------------------------------------------------------------*/

static int
SignedPTPair ()
{
  /* the next 2 bytes, signed */
  int a, b;

  a = GetPTByte ();
  b = GetPTByte ();
  if (a < 128)
    return (a * 256 + b);
  else
    return ((a - 256) * 256 + b);
}
/* SignedPTPair */

/*--------------------------------------------------------------------*/

/* UNUSED: */
#ifdef GET_THREE_PT_BYTES
static int
GetThreePTBytes ()
{
  /* the next 3 bytes, unsigned */
  int a, b, c;

  a = GetPTByte ();
  b = GetPTByte ();
  c = GetPTByte ();
  return ((a * 256 + b) * 256 + c);
}
/* GetThreePTBytes */
#endif /* GET_THREE_PT_BYTES */

/*--------------------------------------------------------------------*/

typedef struct int_or_bytes
{
  boolean b;
  union
    {
      int int_;
      char byt[4];
    }
  UU;
}
int_or_bytes;

/*--------------------------------------------------------------------*/

static int
SignedPTQuad ()
{
  /* the next 4 bytes, signed */
  int w;

  byte3 (w) = GetPTByte ();
  byte2 (w) = GetPTByte ();
  byte1 (w) = GetPTByte ();
  byte0 (w) = GetPTByte ();
  return (w);
}
/* SignedPTQuad */

/*--------------------------------------------------------------------*/

static int
GetNyb ()
{
  /* Return next nybble in PK file. */

  if (bitweight == 0)
    {
      inputbyte = GetPTByte ();
      bitweight = 16;		/* for next call of GetNyb */
      return (inputbyte / 16);	/* high nybble */
    }
  else
    {
      bitweight = 0;		/* for next call of GetNyb */
      return (inputbyte & 15);	/* low nybble */
    }
}
/* GetNyb */

/*--------------------------------------------------------------------*/

static int
PackedNum ()
{
  /* Return next run count using algorithm given in section 23 of PKtype.
     A possible side-effect is to set the global repeatcount value used
     to duplicate the current row.
   */

  int i, j;

  i = GetNyb ();
  if (i == 0)
    {
      do
	{
	  j = GetNyb ();
	  i++;
	}
      while (j == 0);
      while (i > 0)
	{
	  j = j * 16 + GetNyb ();
	  i--;
	}
      return (j + (13 - dynf) * 16 + dynf - 15);
    }
  else if (i <= dynf)
    return i;
  else if (i < 14)
    return ((i - dynf - 1) * 16 + GetNyb () + dynf + 1);
  else
    {
      if (i == 14)		/* nybble = 15 */
	repeatcount = PackedNum ();	/* recursive */
      else
	repeatcount = 1;
      return (PackedNum ());	/* recursive */
    }
}
/* PackedNum */

/*--------------------------------------------------------------------*/

boolean 
GetBitmap (int ht, int wd, int mapadr, int_or_mptr * bitmap)
{
  /* Allocate space for bitmap and fill it in using information from
     character definition starting at mapadr in currently open PK
     file.  Note that the memory used by a loaded bitmap is never
     deallocated.  Each bitmap row uses an integral number of words
     (each 32 bits).  Byte-aligned rows would use about 35% less
     memory but would increase the processing time needed to display
     each bitmap.  It was felt that speed is more important than
     memory.  Return true if the bitmap is obtained, false if function
     fails.
   */

  extern int bitweight;		/* local to "fontreader.c" */

  int_or_bptr wordptr, rowptr;
  int i, j, flagbyte, wordwidth, wordweight, rowsleft, hbit, count, bitmapwords;
  int word;
  Word *bitmapptr = (Word *) NULL;

  wordwidth = (wd + 31) / 32;	/* words in one row of bitmap */
  bitmapwords = ht * wordwidth;	/* memory required by bitmap */

  bitmapptr = (Word *) calloc (bitmapwords, sizeof (Word));
  if (bitmapptr == (Word *) NULL)
    {
      StartText ();
      ResetVDU ();		/* do before message since it might erase screen! */
      FATAL1 ("Out of memory.  Character too big!  size = %d", bitmapwords);
      return false;		/* Not Reached */
    }
  bitmap->UU.mptr = bitmapptr;	/* return start of bitmap */
  wordptr.UU.int_ = bitmap->UU.int_;
  PToffset = mapadr;		/* mapadr = flagbyte offset in PK file */

  flagbyte = GetPTByte ();	/* assume < 240 */
  dynf = flagbyte / 16;		/* dynamic packing variable */
  turnon = ((flagbyte & 15) >= 8);	/* is 1st pixel black? */
  flagbyte &= 7;		/* value of bottom 3 bits */
  if (flagbyte < 4)		/* skip short char preamble */
    PToffset += 10;
  else if (flagbyte < 7)
    PToffset += 16;
  else
    PToffset += 36;

  bitweight = 0;		/* to get 1st inputbyte */
  if (dynf == 14)
    {
      /* raster info is a string of bits in the next (wd * ht + 7) DIV 8 bytes */

      for (i = 1; i <= ht; i++)
	{
	  word = 0;		/* set all bits to 0 */
	  wordweight = 31;	/* leftmost bit */
	  for (j = 1; j <= wd; j++)
	    {
	      if (bitweight == 0)
		{
		  inputbyte = GetPTByte ();
		  bitweight = 8;
		}
	      bitweight--;	/* 7..0 */
	      if ((unsigned) bitweight < 32 && ((1 << bitweight) & inputbyte))
		/* set bit */
		word |= 1 << wordweight;
	      if (wordweight > 0)
		wordweight--;
	      else
		{
		  *wordptr.UU.bptr = word;
		  wordptr.UU.int_ += 4;
		  word = 0;
		  wordweight = 31;
		}
	    }
	  if (wordweight < 31)
	    {
	      *wordptr.UU.bptr = word;
	      wordptr.UU.int_ += 4;	/* start of next word */
	    }
	}
    }
  else
    {
      /* raster info is encoded as run and repeat counts */

      rowsleft = ht;
      hbit = wd;
      repeatcount = 0;
      wordweight = 32;
      word = 0;
      rowptr = wordptr;		/* remember start of row */
      while (rowsleft > 0)
	{
	  count = PackedNum ();
	  while (count > 0)
	    {
	      if (count < wordweight && count < hbit)
		{
		  if (turnon)
		    word = (word | gpower[wordweight]) & (~gpower[wordweight - count]);
		  hbit -= count;
		  wordweight -= count;
		  count = 0;
		  continue;
		}
	      if (count >= hbit && hbit <= wordweight)
		{
		  if (turnon)
		    word = (word | gpower[wordweight]) & (~gpower[wordweight - hbit]);
		  *wordptr.UU.bptr = word;
		  /* end of current row, so duplicate repeatcount times */
		  for (i = 1; i <= repeatcount; i++)
		    {
		      for (j = 1; j <= wordwidth; j++)
			{
			  wordptr.UU.int_ += 4;
			  *wordptr.UU.bptr = *rowptr.UU.bptr;
			  rowptr.UU.int_ += 4;
			}
		    }
		  rowsleft += -repeatcount - 1;
		  repeatcount = 0;
		  word = 0;
		  wordptr.UU.int_ += 4;
		  rowptr = wordptr;	/* remember start of next row */
		  wordweight = 32;
		  count -= hbit;
		  hbit = wd;
		}
	      else
		{
		  if (turnon)
		    word |= gpower[wordweight];
		  *wordptr.UU.bptr = word;
		  wordptr.UU.int_ += 4;
		  word = 0;
		  count -= wordweight;
		  hbit -= wordweight;
		  wordweight = 32;
		}
	    }
	  turnon = !turnon;
	}
    }
  return true;
}
/* GetBitmap */

/*--------------------------------------------------------------------*/

static int 
FixToDVI (int scale, int b0, int b1, int b2, int b3)
/* scale = currfont->scaledsize; */
/* fix width: 4 bytes */
{
  /* Convert the given fix width (made up of 4 bytes) into DVI units
     using the method recommended in DVITYPE.
     Added local scale to avoid changing scaledsize; thanks to Niel Kempson
     for reporting this bug.
   */

  int dviwidth = 0;
  int alpha, beta, temp;

  alpha = scale * 16;
  beta = 16;
  while (scale >= 0x800000)
    {				/* 2^23sp = 128pt */
      scale /= 2;
      beta /= 2;
    }
  temp = ((b3 * scale / 0x100 + b2 * scale) / 0x100 + b1 * scale) / beta;

  if (b0 <= 0)
    dviwidth = temp;
  else if (b0 == 255)
    dviwidth = (temp - alpha);
  else
    {
      dviwidth = 0;		/* keep compiler happy, if necessary */

      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL1 ("Bad TFM width! 1st byte = %d.", b0);
    }

  return dviwidth;
}
/* FixToDVI */

/*--------------------------------------------------------------------*/

#define pkid            89
#define pkpost          245
#define pknoop          246
#define pkpre           247

static void 
PKFillPixelTable (fontinfo * currfont)
{
  /* Fill the pixeltable for currfont^ using the font directory info
     in the currently open PK file.
   */

  int i, j, flagbyte, flagpos;
  int chcode;			/* char. code, assumed to be <= maxTeXchar */
  int packetlen, endofpacket, b0, b1, b2, b3;	/* 4 bytes in TFM width */
  _REC_pixeltable *pix_tab;

  PToffset = 0;			/* move to first byte */

  if (GetPTByte () != pkpre)
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL1 ("Bad PK pre command in `%s'.", currfont->fontspec);
    }
  if (GetPTByte () != pkid)
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL1 ("Bad PK id byte in `%s'.", currfont->fontspec);
    }
  j = GetPTByte ();		/* length of comment */
  PToffset += j + 16;		/* skip rest of preamble */

  for (i = 0; i <= maxTeXchar; i++)
    {
      pix_tab = &currfont->pixelptr[i];
      pix_tab->mapadr = 0;	/* all chars absent initially */
      pix_tab->bitmap.UU.mptr = (Word *) NULL;
    }

  while (true)
    {
      flagpos = PToffset;	/* remember position of flagbyte */
      flagbyte = GetPTByte ();
      if (flagbyte < 240)
	{			/* read character definition */

	  int scale = currfont->scaledsize;	/* For FixToDVI */

	  flagbyte &= 7;	/* value of bottom 3 bits */
	  if (flagbyte < 4)
	    {			/* short char preamble */
	      packetlen = flagbyte * 256 + GetPTByte ();
	      chcode = GetPTByte ();
	      endofpacket = packetlen + PToffset;
	      pix_tab = &currfont->pixelptr[chcode];
	      b1 = GetPTByte ();
	      b2 = GetPTByte ();
	      b3 = GetPTByte ();
	      pix_tab->dwidth = FixToDVI (scale, 0, b1, b2, b3);	/* b0 = 0 */
	      pix_tab->pwidth = GetPTByte ();
	      pix_tab->wd = GetPTByte ();
	      pix_tab->ht = GetPTByte ();
	      pix_tab->xo = SignedPTByte ();
	      pix_tab->yo = SignedPTByte ();
	    }
	  else if (flagbyte < 7)
	    {
	      packetlen = (flagbyte - 4) * 65536 + GetTwoPTBytes ();
	      chcode = GetPTByte ();
	      endofpacket = packetlen + PToffset;
	      pix_tab = &currfont->pixelptr[chcode];
	      b1 = GetPTByte ();
	      b2 = GetPTByte ();
	      b3 = GetPTByte ();
	      pix_tab->dwidth = FixToDVI (scale, 0, b1, b2, b3);	/* b0 = 0 */
	      pix_tab->pwidth = GetTwoPTBytes ();
	      pix_tab->wd = GetTwoPTBytes ();
	      pix_tab->ht = GetTwoPTBytes ();
	      pix_tab->xo = SignedPTPair ();
	      pix_tab->yo = SignedPTPair ();
	    }
	  else
	    {
	      packetlen = SignedPTQuad ();
	      chcode = SignedPTQuad ();
	      endofpacket = packetlen + PToffset;
	      pix_tab = &currfont->pixelptr[chcode];
	      b0 = GetPTByte ();
	      b1 = GetPTByte ();
	      b2 = GetPTByte ();
	      b3 = GetPTByte ();
	      pix_tab->dwidth = FixToDVI (scale, b0, b1, b2, b3);
	      pix_tab->pwidth = SignedPTQuad () / 65536;	/* dx in pixels */
	      PToffset += 4;	/* skip dy */
	      pix_tab->wd = SignedPTQuad ();
	      pix_tab->ht = SignedPTQuad ();
	      pix_tab->xo = SignedPTQuad ();
	      pix_tab->yo = SignedPTQuad ();
	    }
	  pix_tab = &currfont->pixelptr[chcode];	/* position of flagbyte */
	  if (pix_tab->wd == 0 || pix_tab->ht == 0)
	    pix_tab->mapadr = 0;	/* no bitmap */
	  else
	    pix_tab->mapadr = flagpos;
	  PToffset = endofpacket;	/* skip raster info */
	  continue;
	}
      switch (flagbyte)
	{
	case 240:
	case 241:
	case 242:
	case 243:
	  i = 0;
	  for (j = 240; j <= flagbyte; j++)
	    i = i * 256 + GetPTByte ();
	  PToffset += i;	/* skip special parameter */
	  break;
	case 244:		/* skip numspecial param */
	  PToffset += 4;
	  break;
	case pknoop:		/* do nothing */
	  break;
	case pkpost:		/* no more char defs */
	  goto _L888;
	  break;

	default:
	  StartText ();
	  ResetVDU ();		/* let message stay */

	  FATAL1 ("Bad PK flag byte in `%s'.", currfont->fontspec);
	}
    }				/* of LOOP; flagbyte = pkpost */
_L888:;

  /* extended short char preamble */
  /* long char preamble */
}
/* PKFillPixelTable */

#undef pkid
#undef pkpost
#undef pknoop
#undef pkpre

/*--------------------------------------------------------------------*/

static void
ReadTFMIntegers ()
{
  /* Read the first 6 (six) 16-bit integers in the TFM file. */
  /* These give the dimensions of the arrays that constitute the rest */
  /* of the TFM file. */
  /* See TFtoPL section 8. */

  PToffset = 0;			/* start reading at 1st byte in TFM file */
  lf = GetTwoPTBytes ();	/* length of TFM file, in words:  0 <= lf < 2^15. */
  lh = GetTwoPTBytes ();	/* length of header, in words:  2 <= lh. */
  bc = GetTwoPTBytes ();	/* smallest character code in font */
  ec = GetTwoPTBytes ();	/* largest character code in font */
  nw = GetTwoPTBytes ();	/* number of words in width table */
  nh = GetTwoPTBytes ();	/* number of words in height table */

  /* sanity check of lf */
  if (!(0 <= lf && lf < 1 << 15))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL2 ("TFM file length given as:  lf = %d words.  Should have 0 <= lf < %d words.", lf, 1 << 15);
    }
  /* sanity check of lh */
  if (!(2 <= lh))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL1 ("TFM's Header length given as:  lh = %d words.   Should have lh >= 2 (two) words.", lh);
    }
  /* sanity check of bc and ec */
  if (!(0 <= bc && bc - 1 <= ec && ec <= maxTeXchar))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL2 ("First & last char codes = (bc, ec) = (%d, %d).  Should have 0 <= bc <= ec <= maxTeXchar = 255.", bc, ec);
    }
  /* sanity check of nw */
  if (!(0 <= nw && nw < 1 << 15))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL2 ("Number of Width Table words given as: nw = %d.  Should have 0 <= nw < %d words.", nw, 1 << 15);
    }
  /* sanity check of nh */
  if (!(0 <= nh && nh < 1 << 15))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL2 ("Number of Height Table words given as:  nh = %d.  Should have 0 <= nh < %d.", nh, 1 << 15);
    }
}
/* ReadTFMIntegers */

/*--------------------------------------------------------------------*/

static void
ReadTFMCharInfo ()
{
  /* Read the TFMinfo array.  See TFtoPL section 11. */

  int c, i;
  _REC_TFMinfo *tfm_inf;

  PToffset = (6 + lh) * 4;	/* offset of TFMinfo array (in bytes) */
  /* 6 words of dimension info, plus header */
  for (c = bc; c <= ec; c++)
    {
      tfm_inf = &TFMinfo[c];
      tfm_inf->wdindex = GetPTByte () * 4;	/* offset from start of width array */
      i = GetPTByte ();		/* 2nd byte contains htindex and dpindex */
      tfm_inf->htindex = i / 16 * 4;	/* offset from start of height array */
      tfm_inf->dpindex = (i & 15) * 4;	/* offset from start of depth array */
      PToffset += 2;		/* skip itindex and remainder bytes */
    }
}
/* ReadTFMCharInfo */

/*--------------------------------------------------------------------*/

static void
ReadTFMCharMetrics ()
{
  /* Read the charmetrics array using the indices in TFMinfo. */

  int wdbase = lh * 4 + (ec - bc + 1) * 4 + 24;		/* offset of width array */
  int htbase = wdbase + nw * 4;	/* offset of height array */
  int dpbase = htbase + nh * 4;	/* offset of depth array */
  int c;

  for (c = bc; c <= ec; c++)
    {
      _REC_TFMinfo *tfm_inf = &TFMinfo[c];
      _REC_charmetrics *char_met = &charmetrics[c];
      int b;

      PToffset = wdbase + tfm_inf->wdindex;
      for (b = 0; b <= 3; b++)
	char_met->width[b] = GetPTByte ();
      PToffset = htbase + tfm_inf->htindex;
      for (b = 0; b <= 3; b++)
	char_met->height[b] = GetPTByte ();
      PToffset = dpbase + tfm_inf->dpindex;
      for (b = 0; b <= 3; b++)
	char_met->depth[b] = GetPTByte ();
    }
}
/* ReadTFMCharMetrics */

/*--------------------------------------------------------------------*/

static void 
TFMFillPixelTable (fontinfo * currfont)
{
  /* Fill the pixeltable for  * currfont
     (a PostScript or other font for which the PK file is missing),
     using information in the currently open TFM file.
   */

  int c;

  ReadTFMIntegers ();		/* read lf..nh */
  ReadTFMCharInfo ();		/* fill TFMinfo array */
  ReadTFMCharMetrics ();	/* fill charmetrics array */

  for (c = 0; c < bc; c++)	/* chars < bc don't exist */
    currfont->pixelptr[c].mapadr = 0;

  for (c = ec + 1; c <= maxTeXchar; c++)	/* chars > ec don't exist */
    currfont->pixelptr[c].mapadr = 0;

  for (c = bc; c <= ec; c++)
    {
      _REC_pixeltable *pix_tab = &currfont->pixelptr[c];
      _REC_charmetrics *char_met = &charmetrics[c];
      int scale = currfont->scaledsize;		/* For FixToDVI */
      int dheight, pheight, ddepth, pdepth;

      pix_tab->dwidth = FixToDVI (scale,
				  char_met->width[0], char_met->width[1],
				  char_met->width[2], char_met->width[3]);

      dheight = FixToDVI (scale,
			  char_met->height[0], char_met->height[1],
			  char_met->height[2], char_met->height[3]);

      ddepth = FixToDVI (scale,
			 char_met->depth[0], char_met->depth[1],
			 char_met->depth[2], char_met->depth[3]);

      /* convert DVI units to pixels */

      pix_tab->pwidth = XPixelRound (pix_tab->dwidth);
      pheight = YPixelRound (dheight);
      pdepth = YPixelRound (ddepth);

      /* Since we don't have access to PK bitmap info,
         we will have to use the TFM width/height/depth info
         to approximate wd, ht, xo, yo.
       */

      pix_tab->wd = pix_tab->pwidth;
      pix_tab->wd -= pix_tab->wd / 8;	/* better approximation */
      pix_tab->ht = pheight + pdepth;
      pix_tab->xo = 0;
      pix_tab->yo = pheight - 1;
      if (pix_tab->wd == 0 || pix_tab->ht == 0)		/* anything but 0 */
	pix_tab->mapadr = 0;	/* char blank or not in font */
      else
	pix_tab->mapadr = 1;
      pix_tab->bitmap.UU.mptr = (Word *) NULL;
    }
}
/* TFMFillPixelTable */

/*--------------------------------------------------------------------*/


static void 
AbsentFillPixelTable (fontinfo * currfont)
{
  /* Fill the pixeltable for *currfont
     * (a PostScript or other font that is missing and cannot be replaced),
     * using information in the DVI file, since we have nothing else.
     *
     * Updated (Wed 9 June 1993) to use cmr10 info., as that is the most
     * common font in most present-day documents.
   */

  int c;

  for (c = 0; c <= maxTeXchar; c++)
    {
      _REC_pixeltable *pix_tab = &currfont->pixelptr[c];

      /* scaled size of font in DVI units */
      int scale = currfont->scaledsize;		/* For character size estimate */
      int dheight, ddepth;	/* estimated height and depth, in DVI units */
      int pheight, pdepth;	/* same, in pixels */

      /* Let character be a square, scaledsize high and wide, zero depth. */
      /* For "example.tex", this width and height are not too bad. */
      pix_tab->dwidth = scale / 2;	/* wild, hazardous guess */
      dheight = scale;
      ddepth = 0;

      /* convert DVI units to pixels */
      pix_tab->pwidth = XPixelRound (pix_tab->dwidth);
      pheight = YPixelRound (dheight);
      pdepth = YPixelRound (ddepth);

      /* Since we don't have access to PK bitmap or to TFM metric info,
         we will have to use the guessed (DVI) width/height/depth info
         to approximate wd, ht, xo, yo.
       */

      pix_tab->wd = pix_tab->pwidth;
      pix_tab->wd -= pix_tab->wd / 8;	/* better approximation */
      pix_tab->ht = pheight + pdepth;
      pix_tab->xo = 0;
      pix_tab->yo = pheight - 1;
      if (pix_tab->wd == 0 || pix_tab->ht == 0)		/* anything but 0 */
	pix_tab->mapadr = 0;	/* char blank or not in font */
      else
	pix_tab->mapadr = 1;
      pix_tab->bitmap.UU.mptr = (Word *) NULL;
    }
}
/* AbsentFillPixelTable */

/*--------------------------------------------------------------------*/

void 
PixelTableRoutine (fontinfo * currfont)
{
  /* DVIReader has just allocated a new pixeltable for currfont, and
     calls this routine from InterpretPage only ONCE per font
     (the first time the font is used).
     If this is the first time we've seen the font,
     then we build fontspec first.
     (Note that ShowStatistics, in the main program, may call BuildFontSpec
     first.)
     If we can't open the font file, we return dummy_pk or dummy_tfm values,
     but using the current font's scaledsize.
   */

  if (!CheckFontPtr (currfont))
    return;

  /* Try to find and fopen (& fclose) PK file; if that fails, try TFM file. */
  if (currfont->fontspeclen == 0)
    BuildFontSpec (currfont);

  if (currfont->fontexists && !OpenFontFile (currfont->fontspec))
    {
      StartText ();
      ResetVDU ();		/* let message stay */

      FATAL2 ("fopen-ed but couldn't open file `%s' for font `%s'",
	      currfont->fontspec, currfont->fontname);
    }
  /* gt - is this right when a dummy font is used? */

  if (currfont->fontexists)
    {
      if (currfont->pkfont)
	PKFillPixelTable (currfont);
      else
	TFMFillPixelTable (currfont);

      CloseFontFile ();
    }
  else
    {
      AbsentFillPixelTable (currfont);
    }
}
/* PixelTableRoutine */

/*--------------------------------------------------------------------*/

void
InitFontReader ()
{
  /* This routine initializes some global variables. */

  int i;

  gpower[0] = 0;
  for (i = 1; i <= 32; i++)	/* used in GetBitmap */
    gpower[i] = gpower[i - 1] | (1 << (i - 1));
}
/* InitFontReader */

/*--------------------------------------------------------------------*/

/* end fontreader.c */