type1.c

source code: Covert TXT to PDF

  }
 
  oldvert = newvert; oldverthalf = newverthalf;
  oldhor  = newhor;  oldhorhalf  = newhorhalf;
 
  return p;
}
 
/******************************************************/
/* Subroutines and statics for the Type1Char routines */
/******************************************************/
 
static int strindex; /* index into PostScript string being interpreted */
static DOUBLE currx, curry; /* accumulated x and y values for hints */
 
struct callstackentry {
  psobj *currstrP;        /* current CharStringP */
  int currindex;          /* current strindex */
  unsigned short currkey; /* current decryption key */
  };
 
static DOUBLE Stack[MAXSTACK];
static int Top;
static struct callstackentry CallStack[MAXCALLSTACK];
static int CallTop;
static DOUBLE PSFakeStack[MAXPSFAKESTACK];
static int PSFakeTop;
 
static int ClearStack()
{
  Top = -1;
  return(0);
  
}
 
static int Push(Num)
        DOUBLE Num;
{
  if (++Top < MAXSTACK) Stack[Top] = Num;
  else Error0i("Push: Stack full\n");
  return(0);
  
}
 
static int ClearCallStack()
{
  CallTop = -1;
  return(0);
}
 
static int PushCall(CurrStrP, CurrIndex, CurrKey)
  psobj *CurrStrP;
  int CurrIndex;
  unsigned short CurrKey;
{
  if (++CallTop < MAXCALLSTACK) {
    CallStack[CallTop].currstrP = CurrStrP;   /* save CharString pointer */
    CallStack[CallTop].currindex = CurrIndex; /* save CharString index */
    CallStack[CallTop].currkey = CurrKey;     /* save decryption key */
  }
  else Error0i("PushCall: Stack full\n");
  return(0);
}
 
static int PopCall(CurrStrPP, CurrIndexP, CurrKeyP)
  psobj **CurrStrPP;
  int *CurrIndexP;
  unsigned short *CurrKeyP;
{
  if (CallTop >= 0) {
    *CurrStrPP = CallStack[CallTop].currstrP; /* restore CharString pointer */
    *CurrIndexP = CallStack[CallTop].currindex; /* restore CharString index */
    *CurrKeyP = CallStack[CallTop--].currkey;   /* restore decryption key */
  }
  else Error0i("PopCall: Stack empty\n");
  return(0);
}

 
static int ClearPSFakeStack()
{
  PSFakeTop = -1;
  return(0);
}
 
/* PSFakePush: Pushes a number onto the fake PostScript stack */
static int PSFakePush(Num)
  DOUBLE Num;
{
  if (++PSFakeTop < MAXPSFAKESTACK) PSFakeStack[PSFakeTop] = Num;
  else Error0i("PSFakePush: Stack full\n");
  return(0);
}
 
/* PSFakePop: Removes a number from the top of the fake PostScript stack */
static DOUBLE PSFakePop ()
{
  if (PSFakeTop >= 0) return(PSFakeStack[PSFakeTop--]);
  
  else Error0d("PSFakePop : Stack empty\n");

  /*NOTREACHED*/
}
 
/***********************************************************************/
/* Center a stem on the pixel grid -- used by HStem3 and VStem3        */
/***********************************************************************/
static struct segment *CenterStem(edge1, edge2)
    DOUBLE edge1;
    DOUBLE edge2;
{
  int idealwidth, verticalondevice;
  DOUBLE leftx, lefty, rightx, righty, center, width;
  DOUBLE widthx, widthy;
  DOUBLE shift, shiftx, shifty;
  DOUBLE Xpixels, Ypixels;
  struct segment *p;
 
  p = Loc(CharSpace, edge1, 0.0);
  QueryLoc(p, IDENTITY, &leftx, &lefty);
 
  p = Join(p, Loc(CharSpace, edge2, 0.0));
  QueryLoc(p, IDENTITY, &rightx, &righty);
  Destroy(p);
 
  widthx = FABS(rightx - leftx);
  widthy = FABS(righty - lefty);
 
  if (widthy <= EPS) { /* verticalondevice hint */
    verticalondevice = TRUE;
    center = (rightx + leftx) / 2.0;
    width = widthx;
  }
  else if (widthx <= EPS) { /* horizontal hint */
    verticalondevice = FALSE;
    center = (righty + lefty) / 2.0;
    width = widthy;
  }
  else { /* neither horizontal nor verticalondevice and not oblique */
    return (NULL);
  }
 
  idealwidth = ROUND(width);
  if (idealwidth == 0) idealwidth = 1;
  if (ODD(idealwidth)) {       /* is ideal width odd? */
    /* center stem over pixel */
    shift = FLOOR(center) + 0.5 - center;
  }
  else {
    /* align stem on pixel boundary */
    shift = ROUND(center) - center;
  }
 
  if (verticalondevice) {
    shiftx = shift;
    shifty = 0.0;
  } else {
    shifty = shift;
    shiftx = 0.0;
  }
 
  p = Loc(IDENTITY, shiftx, shifty);
  QueryLoc(p, CharSpace, &Xpixels, &Ypixels);
  wsoffsetX = Xpixels; wsoffsetY = Ypixels;
  currx += wsoffsetX; curry += wsoffsetY;
 
  return (p);
}
 
/*-----------------------------------------------------------------------
  Decrypt - From Adobe Type 1 book page 63, with some modifications
-----------------------------------------------------------------------*/
#define KEY 4330 /* Initial key (seed) for CharStrings decryption */
#define C1 52845 /* Multiplier for pseudo-random number generator */
#define C2 22719 /* Constant for pseudo-random number generator */
 
static unsigned short r; /* Pseudo-random sequence of keys */
 
static unsigned char Decrypt(cipher)
unsigned char cipher;
{
  unsigned char plain;
 
  plain = cipher ^ (r >> 8);
  r = (cipher + r) * C1 + C2;
  return plain;
}
 
/* Get the next byte from the codestring being interpreted */
static int DoRead(CodeP)
  int *CodeP;
{
  if (strindex >= CharStringP->len) return(FALSE); /* end of string */
  /* We handle the non-documented Adobe convention to use lenIV=-1 to
     suppress charstring encryption. */
  if (blues->lenIV==-1) {
    *CodeP = (unsigned char) CharStringP->data.stringP[strindex++];
  }
  else { 
    *CodeP = Decrypt((unsigned char) CharStringP->data.stringP[strindex++]);
  }
  
  return(TRUE);
}
 
/* Strip blues->lenIV bytes from CharString and update encryption key */
/* (the lenIV entry in the Private dictionary specifies the number of */
/* random bytes at the beginning of each CharString; default is 4)    */
static void StartDecrypt()
{
  int Code;
 
  r = KEY; /* Initial key (seed) for CharStrings decryption */
  for (strindex = 0; strindex < blues->lenIV;){
    if (!DoRead(&Code)) /* Read a byte and update decryption key */
      Error0v("StartDecrypt: Premature end of CharString\n");
  }
  
}

#undef DecodeDebug

static int Decode(Code)
  int Code;
{
  int Code1, Code2, Code3, Code4;
 
  if (Code <= 31){                           /* Code is [0,31]    */
#ifdef DecodeDebug
    fprintf(stderr, "Decode: Code=%d -> Command\n", Code);
#endif
    DoCommand(Code);
  }
  else if (Code <= 246){                     /* Code is [32,246]  */
#ifdef DecodeDebug
    fprintf(stderr, "Decode: Code=%d -> number=%f\n",
	    Code, (DOUBLE)(Code-139));
#endif
    Push((DOUBLE)(Code - 139));
  }
  else if (Code <= 250) {                   /* Code is [247,250] */
    if (!DoRead(&Code2)) goto ended;
#ifdef DecodeDebug
    fprintf(stderr, "Decode: Code=%d next Code=%d -> number=%f\n",
	    Code, Code2, (DOUBLE)(((Code - 247) << 8) + Code2 + 108));
#endif
    Push((DOUBLE)(((Code - 247) << 8) + Code2 + 108));
  }
  else if (Code <= 254) {                   /* Code is [251,254] */
    if (!DoRead(&Code2)) goto ended;
#ifdef DecodeDebug
    fprintf(stderr, "Decode: Code=%d, next Code=%d -> number=%f\n",
	    Code, Code2, (DOUBLE)( -((Code - 251) << 8) - Code2 - 108));
#endif
    Push((DOUBLE)( -((Code - 251) << 8) - Code2 - 108));
  }
  else {                                    /* Code is 255 */
    if (!DoRead(&Code1)) goto ended;
    if (!DoRead(&Code2)) goto ended;
    if (!DoRead(&Code3)) goto ended;
    if (!DoRead(&Code4)) goto ended;
#ifdef DecodeDebug
    fprintf(stderr, "Decode: Code=255, Code1=%d, Code2=%d, Code3=%d, Code4=%d -> number=%f\n",
	    Code1, Code2, Code3, Code4,
	    (DOUBLE)((((((Code1<<8) + Code2)<<8) + Code3)<<8) + Code4));
#endif
    Push((DOUBLE)((((((Code1<<8) + Code2)<<8) + Code3)<<8) + Code4));
  }
  return(0);
 
ended: Error0i("Decode: Premature end of Type 1 CharString");
}

#undef DoCommandDebug 

/* Interpret a command code */
static int DoCommand(Code)
  int Code;
{
  switch(Code) {
    case HSTEM: /* |- y dy HSTEM |- */
#ifdef DoCommandDebug
      printf("DoCommand: HStem\n");
#endif
      /* Vertical range of a horizontal stem zone */
      if (Top < 1) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      HStem(Stack[0], Stack[1]);
      ClearStack();
      break;
    case VSTEM: /* |- x dx VSTEM |- */
#ifdef DoCommandDebug
      printf("DoCommand: VStem\n");
#endif
      /* Horizontal range of a vertical stem zone */
      if (Top < 1) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      VStem(Stack[0], Stack[1]);
      ClearStack();
      break;
    case VMOVETO: /* |- dy VMOVETO |- */
#ifdef DoCommandDebug
      printf("DoCommand: VMoveto\n");
#endif
      /* Vertical MOVETO, equivalent to 0 dy RMOVETO */
      if (Top < 0) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      RMoveTo(0.0, Stack[0]);
      ClearStack();
      break;
    case RLINETO: /* |- dx dy RLINETO |- */
#ifdef DoCommandDebug
      printf("DoCommand: RLineto\n");
#endif
      /* Like RLINETO in PostScript */
      if (Top < 1) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      RLineTo(Stack[0], Stack[1]);
      ClearStack();
      break;
    case HLINETO: /* |- dx HLINETO |- */
#ifdef DoCommandDebug
      printf("DoCommand: HLineto\n");
#endif
      /* Horizontal LINETO, equivalent to dx 0 RLINETO */
      if (Top < 0) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      RLineTo(Stack[0], 0.0);
      ClearStack();
      break;
    case VLINETO: /* |- dy VLINETO |- */
#ifdef DoCommandDebug
      printf("DoCommand: VLineto\n");
#endif
      /* Vertical LINETO, equivalent to 0 dy RLINETO */
      if (Top < 0) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      RLineTo(0.0, Stack[0]);
      ClearStack();
      break;
    case RRCURVETO:
#ifdef DoCommandDebug
      printf("DoCommand: RRCurveto\n");
#endif
      /* |- dx1 dy1 dx2 dy2 dx3 dy3 RRCURVETO |- */
      /* Relative RCURVETO, equivalent to dx1 dy1 */
      /* (dx1+dx2) (dy1+dy2) (dx1+dx2+dx3) */
      /* (dy1+dy2+dy3) RCURVETO in PostScript */
      if (Top < 5) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      RRCurveTo(Stack[0], Stack[1], Stack[2], Stack[3],
        Stack[4], Stack[5]);
      ClearStack();
      break;
    case CLOSEPATH: /* - CLOSEPATH |- */
#ifdef DoCommandDebug
      printf("DoCommand: ClosePath\n");
#endif
      /* Closes a subpath without repositioning the */
      /* current point */
      DoClosePath();
      ClearStack();
      break;
    case CALLSUBR: /* subr# CALLSUBR - */
#ifdef DoCommandDebug
      printf("DoCommand: CallSubr\n");
#endif
      /* Calls a CharString subroutine with index */
      /* subr# from the Subrs array */
      if (Top < 0) Error1i("DoCommand: Stack low\n (Code=%d)", Code);
      CallSubr((int)Stack[Top--]);
      break;
    case RETURN: /* - RETURN - */
#ifdef DoCommandDebug
      printf("DoCommand: Return\n");
#endif
      /* Returns from a Subrs array CharString */
      /* subroutine called with CALLSUBR */
      Return();
      break;
    case ESCAPE: /* ESCAPE to two-byte command code */
#ifdef DoCommandDebug
      printf("DoCommand: Escape to 2 Byte Code (Code=%d)\n", Code);
#endif
      if (!DoRead(&Code)) Error0i("DoCommand: ESCAPE is last byte\n");
      Escape(Code);
      break;
    case HSBW: /* |- sbx wx HSBW |- */
#ifdef DoCommandDebug
      printf("DoCommand: HSBW\n");
#endif
      /* Set the left sidebearing point to (sbx,0), */
      /* set the character width vector to (wx,0). */
      /* Equivalent to sbx 0 wx 0 SBW.  Space */
      /* character should have sbx = 0 */
      if (Top < 1) Error1i("DoCommand: Stack low (Code=%d)\n", Code);
      Sbw(Stack[0], 0.0, Stack[1], 0.0);
      ClearStack();
      break;
    case ENDCHAR: /* - ENDCHAR |- */
#ifdef DoCommandDebug
      printf("DoCommand: EndChar\n");
#endif
      /* Finishes a CharString outline */
      EndChar();