mimetex.c

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 *		    case-insensitive test to make sure it contains 'domain'
 *		    as a substring.  If given several 'domain's (second form)
 *		    then HTTP_REFERER must contain either 'domain1' or
 *		    'domain2', etc, as a (case-insensitive) substring.
 *		    If HTTP_REFERER fails to contain a substring matching
 *		    any of these domain(s), mimeTeX emits an error message
 *		    image corresponding to the expression specified by
 *		    the  invalid_referer_msg  string defined in main().
 *		    Note: if HTTP_REFERER is not an environment variable,
 *		    mimeTeX correctly generates the requested expression
 *		    (i.e., no referer error).
 *		-DWARNINGS=n  -or-
 *		-DNOWARNINGS
 *		    If an expression submitted to mimeTeX contains an
 *		    unrecognzied escape sequence, e.g., "y=x+\abc+1", then
 *		    mimeTeX generates a gif image containing an embedded
 *		    warning in the form "y=x+[\abc?]+1".  If you want these
 *		    warnings suppressed, -DWARNINGS=0 or -DNOWARNINGS tells
 *		    mimeTeX to ignore unrecognized symbols, and the rendered
 *		    image is "y=x++1" instead.
 *		-DWHITE
 *		    MimeTeX usually renders black symbols on a white
 *		    background.  This option renders white symbols on
 *		    a black background instead.
 *	      o	See individual function entry points for further comments.
 *	      o	The font information in texfonts.h was produced by multiple
 *		runs of gfuntype, one run per struct (i.e., one run per font
 *		family at a particular size).  See gfuntype.c, and also
 *		mimetex.html#fonts, for details.
 *	      o	mimetex.c contains library functions implementing a raster
 *		datatype, functions to manipulate rasterized .mf fonts
 *		(see gfuntype.c which rasterizes .mf fonts), functions
 *		to parse LaTeX expressions, etc.  A complete list of
 *		mimetex.c functions is above.  See their individual entry
 *		points below for further comments.
 *		   All these functions eventually belong in several
 *		different modules, possibly along the lines suggested
 *		by the divisions above.  But until the best decomposition
 *		becomes clear, it seems better to keep mimetex.c
 *		neatly together, avoiding a bad decomposition that
 *		becomes permanent by default.
 *	      o	The "main" reusable function is rasterize(),
 *		which takes a string like "f(x)=\int_{-\infty}^xe^{-t^2}dt"
 *		and returns a (sub)raster representing it as a bit or bytemap.
 *		Your application can do anything it likes with this pixel map.
 *		MimeTeX just outputs it, either as a mime xbitmap or as a gif.
 * --------------------------------------------------------------------------
 * Revision History:
 * 09/18/02	J.Forkosh	Installation.
 * 12/11/02	J.Forkosh	Version 1.00 released.
 * 07/04/03	J.Forkosh	Version 1.01 released.
 * 10/17/03	J.Forkosh	Version 1.20 released.
 * 12/21/03	J.Forkosh	Version 1.30 released.
 * 02/01/04	J.Forkosh	Version 1.40 released.
 * 10/02/04	J.Forkosh	Version 1.50 released.
 * 11/30/04	J.Forkosh	Version 1.60 released.
 *
 ****************************************************************************/

/* -------------------------------------------------------------------------
header files and macros
-------------------------------------------------------------------------- */
/* --- standard headers --- */
#include <stdio.h>
#include <stdlib.h>
/*#include <unistd.h>*/
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <time.h>

/* --- windows-specific header info --- */
#ifndef WINDOWS			/* -DWINDOWS not supplied by user */
  #if defined(_WINDOWS) || defined(_WIN32) || defined(WIN32) \
  ||  defined(DJGPP)		/* try to recognize windows compilers */ \
  ||  defined(_USRDLL)		/* must be WINDOWS if compiling for DLL */
    #define WINDOWS		/* signal windows */
  #endif
#endif
#ifdef WINDOWS			/* Windows opens stdout in char mode, and */
  #include <fcntl.h>		/* precedes every 0x0A with spurious 0x0D.*/
  #include <io.h>		/* So emitcache() issues a Win _setmode() */
				/* call to put stdout in binary mode. */
  #if defined(_O_BINARY) && !defined(O_BINARY)  /* only have _O_BINARY */
    #define O_BINARY _O_BINARY	/* make O_BINARY available, etc... */
    #define setmode  _setmode
    #define fileno   _fileno
  #endif
  #if defined(_O_BINARY) || defined(O_BINARY)  /* setmode() now available */
    #define HAVE_SETMODE	/* so we'll use setmode() */
  #endif
  #if defined(_MSC_VER) && defined(_DEBUG) /* MS VC++ in debug mode */
    /* to show source file and line numbers where memory leaks occur... */
    #define _CRTDBG_MAP_ALLOC	/* ...include this debug macro */
    #include <crtdbg.h>		/* and this debug library */
  #endif
  #define ISWINDOWS 1
#else
  #define ISWINDOWS 0
#endif

/* --- check for supersampling or low-pass anti-aliasing --- */
#ifdef SS
  #define ISSUPERSAMPLING 1
  #ifndef AAALGORITHM
    #define AAALGORITHM 1		/* default supersampling algorithm */
  #endif
  #ifndef AA				/* anti-aliasing not explicitly set */
    #define AA				/* so define it ourselves */
  #endif
  #ifndef SSFONTS			/* need supersampling fonts */
    #define SSFONTS
  #endif
#else
  #define ISSUPERSAMPLING 0
  #ifndef AAALGORITHM
    #define AAALGORITHM 2		/* default lowpass algorithm */
  #endif
#endif

/* --- set aa (and default gif) if any anti-aliasing options specified --- */
#if defined(AA) || defined(GIF) || defined(PNG) \
||  defined(CENTERWT) || defined(ADJACENTWT) || defined(CORNERWT) \
||  defined(MINADJACENT) || defined(MAXADJACENT)
  #if !defined(GIF) && !defined(AA)	/* aa not explicitly specified */
    #define AA				/* so define it ourselves */
  #endif
  #if !defined(GIF) && !defined(PNG)	/* neither gif nor png specified */
    #define GIF				/* so default to gif */
  #endif
#endif
/* --- resolve output option inconsistencies --- */
#if defined(XBITMAP)			/* xbitmap supercedes gif and png */
  #ifdef AA
    #undef AA
  #endif
  #ifdef GIF
    #undef GIF
  #endif
  #ifdef PNG
    #undef PNG
  #endif
#endif

/* --- decide whether to compile main() --- */
#if defined(XBITMAP) || defined(GIF) || defined(PNG)
  #define DRIVER			/* driver will be compiled */
  /* --- check whether or not to perform http_referer check --- */
  #ifndef REFERER			/* all http_referer's allowed */
    #define REFERER NULL
  #endif
  /* --- max query_string length if no http_referer supplied --- */
  #ifndef NOREFMAXLEN
    #define NOREFMAXLEN 9999		/* default to any length query */
  #endif
#else
  #define NOTEXFONTS			/* texfonts not required */
#endif

/* --- application headers --- */
#if !defined(NOTEXFONTS) && !defined(TEXFONTS)
  #define TEXFONTS			/* to include texfonts.h */
#endif
#include "mimetex.h"
/* --- info needed when gif image returned in memory buffer --- */
#ifdef GIF				/* compiling along with gifsave.c */
  extern int gifSize;
  extern int maxgifSize;
#else					/* or just set dummy values */
  static int gifSize=0, maxgifSize=0;
#endif

/* -------------------------------------------------------------------------
adjustable default values
-------------------------------------------------------------------------- */
/* --- anti-aliasing parameters --- */
#ifndef	CENTERWT
  /*#define CENTERWT 32*/		/* anti-aliasing centerwt default */
  /*#define CENTERWT 10*/		/* anti-aliasing centerwt default */
  #define CENTERWT 8			/* anti-aliasing centerwt default */
#endif
#ifndef	ADJACENTWT
  /*#define ADJACENTWT 3*/		/* anti-aliasing adjacentwt default*/
  #define ADJACENTWT 2			/* anti-aliasing adjacentwt default*/
#endif
#ifndef	CORNERWT
  #define CORNERWT 1			/* anti-aliasing cornerwt default*/
#endif
#ifndef	MINADJACENT
  #define MINADJACENT 6			/*anti-aliasing minadjacent default*/
#endif
#ifndef	MAXADJACENT
  #define MAXADJACENT 8			/*anti-aliasing maxadjacent default*/
#endif
/* --- variables for anti-aliasing parameters --- */
GLOBAL(int,centerwt,CENTERWT);		/*lowpass matrix center pixel wt */
GLOBAL(int,adjacentwt,ADJACENTWT);	/*lowpass matrix adjacent pixel wt*/
GLOBAL(int,cornerwt,CORNERWT);		/*lowpass matrix corner pixel wt */
GLOBAL(int,minadjacent,MINADJACENT);	/* darken if>=adjacent pts black*/
GLOBAL(int,maxadjacent,MAXADJACENT);	/* darken if<=adjacent pts black */
GLOBAL(int,weightnum,1);		/* font wt, */
GLOBAL(int,maxaaparams,4);		/* #entries in table */
/* --- parameter values by font weight --- */
#define	aaparameters struct aaparameters_struct /* typedef */
aaparameters
  { int	centerwt;			/* lowpass matrix center   pixel wt*/
    int	adjacentwt;			/* lowpass matrix adjacent pixel wt*/
    int cornerwt;			/* lowpass matrix corner   pixel wt*/
    int	minadjacent;			/* darken if >= adjacent pts black */
    int	maxadjacent;			/* darken if <= adjacent pts black */
    int fgalias,fgonly,bgalias,bgonly; } ; /* aapnm() params */
STATIC aaparameters aaparams[]		/* set params by weight */
  #ifdef INITVALS
  =
  { /* ----------------------------------------------------
    centerwt adj corner minadj max  fgalias,only,bgalias,only
    ------------------------------------------------------- */
	{ 64,  1,  1,    6,  8,     1,0,0,0 },	/* 0 = light */
	{ CENTERWT,ADJACENTWT,CORNERWT,MINADJACENT,MAXADJACENT,1,0,0,0 },
	{ 8,   1,  1,    5,  8,     1,0,0,0 },	/* 2 = semibold */
	{ 8,   2,  1,    4,  9,     1,0,0,0 }	/* 3 = bold */
  } /* --- end-of-aaparams[] --- */
  #endif
  ;

/* -------------------------------------------------------------------------
other variables
-------------------------------------------------------------------------- */
/* --- black on white background (default), or white on black --- */
#ifdef WHITE
  #define ISBLACKONWHITE 0		/* white on black background */
#else
  #define ISBLACKONWHITE 1		/* black on white background */
#endif
/* --- colors --- */
#define	BGRED   (ISBLACKONWHITE?255:0)
#define	BGGREEN (ISBLACKONWHITE?255:0)
#define	BGBLUE  (ISBLACKONWHITE?255:0)
#ifndef	FGRED
  #define FGRED   (ISBLACKONWHITE?0:255)
#endif
#ifndef	FGGREEN
  #define FGGREEN (ISBLACKONWHITE?0:255)
#endif
#ifndef	FGBLUE
  #define FGBLUE  (ISBLACKONWHITE?0:255)
#endif
/* --- "smash" margin (0 means no smashing) --- */
#ifndef SMASHMARGIN
  #ifdef NOSMASH
    #define SMASHMARGIN 0
  #else
    #define SMASHMARGIN 3
  #endif