mimetex.c

完美的在线教育系统

/* --- allocate rotated raster with flipped width<-->height --- */
if ( (rotated = new_raster(height,width,pixsz)) /* flip width,height */
!=   NULL )				/* check that allocation succeeded */
  /* --- fill rotated raster --- */
  for ( irow=0; irow<height; irow++ )	/* for each row of rp */
    for ( icol=0; icol<width; icol++ )	/* and each column of rp */
      {	int value = getpixel(rp,irow,icol);
	/* setpixel(rotated,icol,irow,value); } */
	setpixel(rotated,icol,(height-1-irow),value); }
return ( rotated );			/* return rotated raster to caller */
} /* --- end-of-function rastrot() --- */


/* ==========================================================================
 * Function:	rastput ( target, source, top, left, isopaque )
 * Purpose:	Overlays source onto target,
 *		with the 0,0-bit of source onto the top,left-bit of target.
 * --------------------------------------------------------------------------
 * Arguments:	target (I)	ptr to target raster struct
 *		source (I)	ptr to source raster struct
 *		top (I)		int containing 0 ... target->height - 1
 *		left (I)	int containing 0 ... target->width - 1
 *		isopaque (I)	int containing false (zero) to allow
 *				original 1-bits of target to "show through"
 *				0-bits of source.
 * --------------------------------------------------------------------------
 * Returns:	( int )		1 if completed successfully,
 *				or 0 otherwise (for any error).
 * --------------------------------------------------------------------------
 * Notes:
 * ======================================================================= */
/* --- entry point --- */
int	rastput ( raster *target, raster *source,
		int top, int left, int isopaque )
{
/* -------------------------------------------------------------------------
Allocations and Declarations
-------------------------------------------------------------------------- */
int	irow, icol,		/* indexes over source raster */
	twidth=target->width, theight=target->height, /*target width,height*/
	tpix, ntpix = twidth*theight; /* #pixels in target */
int	isfatal = 0,		/* true to abend on out-of-bounds error */
	isstrict = 0/*1*/,	/* true for strict bounds check - no "wrap"*/
	isokay = 1;		/* true if no pixels out-of-bounds */
/* -------------------------------------------------------------------------
superimpose source onto target, one bit at a time
-------------------------------------------------------------------------- */
if ( isstrict && (top<0 || left<0) )		/* args fail strict test */
 isokay = 0;					/* so just return error */
else
 for ( irow=0; irow<source->height; irow++ )	/* for each scan line */
  {
  tpix = (top+irow)*target->width + left - 1;	/*first target pixel (-1)*/
  for ( icol=0; icol<source->width; icol++ )	/* each pixel in scan line */
    {
    int svalue = getpixel(source,irow,icol);	/* source pixel value */
    ++tpix;					/* bump target pixel */
    if ( msgfp!=NULL && msglevel>=9999 )	/* debugging output */
      {	fprintf(msgfp,"rastput> tpix,ntpix=%d,%d top,irow,theight=%d,%d,%d "
	"left,icol,twidth=%d,%d,%d\n", tpix,ntpix, top,irow,theight,
	left,icol,twidth);  fflush(msgfp); }
    if ( tpix >= ntpix				/* bounds check failed */
    ||   (isstrict && (irow+top>=theight || icol+left>=twidth)) )
      {	isokay = 0;				/* reset okay flag */
	if ( isfatal ) goto end_of_job;		/* abort if error is fatal */
	else break; }				/*or just go on to next row*/
    if ( tpix >= 0 )				/* bounds check okay */
     if ( svalue!=0 || isopaque )		/*got dark or opaque source*/
      setpixel(target,irow+top,icol+left,svalue); /*overlay source on target*/
    } /* --- end-of-for(icol) --- */
  } /* --- end-of-for(irow) --- */
/* -------------------------------------------------------------------------
Back to caller with 1=okay, 0=failed.
-------------------------------------------------------------------------- */
end_of_job:
  return ( isokay /*isfatal? (tpix<ntpix? 1:0) : 1*/ );
} /* --- end-of-function rastput() --- */


/* ==========================================================================
 * Function:	rastcompose ( sp1, sp2, offset2, isalign, isfree )
 * Purpose:	Overlays sp2 on top of sp1, leaving both unchanged
 *		and returning a newly-allocated composite subraster.
 *		Frees/deletes input sp1 and/or sp2 depending on value
 *		of isfree (0=none, 1=sp1, 2=sp2, 3=both).
 * --------------------------------------------------------------------------
 * Arguments:	sp1 (I)		subraster *  to "underneath" subraster,
 *				whose baseline is preserved
 *		sp2 (I)		subraster *  to "overlaid" subraster
 *		offset2 (I)	int containing 0 or number of pixels
 *				to horizontally shift sp2 relative to sp1,
 *				either positive (right) or negative
 *		isalign (I)	int containing 1 to align baselines,
 *				or 0 to vertically center sp2 over sp1
 *		isfree (I)	int containing 1=free sp1 before return,
 *				2=free sp2, 3=free both, 0=free none.
 * --------------------------------------------------------------------------
 * Returns:	( subraster * )	pointer to constructed subraster
 *				or  NULL for any error
 * --------------------------------------------------------------------------
 * Notes:
 * ======================================================================= */
/* --- entry point --- */
subraster *rastcompose ( subraster *sp1, subraster *sp2, int offset2,
			int isalign, int isfree )
{
/* -------------------------------------------------------------------------
Allocations and Declarations
-------------------------------------------------------------------------- */
subraster *new_subraster(), *sp=(subraster *)NULL; /* returned subraster */
raster	*rp=(raster *)NULL;		/* new composite raster in sp */
int	delete_subraster();		/* in case isfree non-zero */
int	rastput();			/*place sp1,sp2 in composite raster*/
int	base1   = sp1->baseline,	/*baseline for underlying subraster*/
	height1 = (sp1->image)->height,	/* height for underlying subraster */
	width1  = (sp1->image)->width,	/* width for underlying subraster */
	pixsz1  = (sp1->image)->pixsz,	/* pixsz for underlying subraster */
	base2   = sp2->baseline,	/*baseline for overlaid subraster */
	height2 = (sp2->image)->height,	/* height for overlaid subraster */
	width2  = (sp2->image)->width,	/* width for overlaid subraster */
	pixsz2  = (sp2->image)->pixsz;	/* pixsz for overlaid subraster */
int	height=0, width=0, pixsz=0, base=0; /* overlaid composite */
/* -------------------------------------------------------------------------
Initialization
-------------------------------------------------------------------------- */
/* --- determine height, width and baseline of composite raster --- */
if ( isalign )				/* baselines of sp1,sp2 aligned */
  { height = max2(base1+1,base2+1)	/* max height above baseline */
           + max2(height1-base1-1,height2-base2-1); /*+ max descending below*/
    base   = max2(base1,base2); }	/* max space above baseline */
else					/* baselines not aligned */
  { height = max2(height1,height2);	/* max height */
    base   = base1 + (height-height1)/2; } /* baseline for sp1 */
width      = max2(width1,width2+abs(offset2)); /* max width */
pixsz      = max2(pixsz1,pixsz2);	/* bitmap,bytemap becomes bytemap */
/* -------------------------------------------------------------------------
allocate concatted composite subraster
-------------------------------------------------------------------------- */
/* --- allocate returned subraster (and then initialize it) --- */
if ( (sp=new_subraster(width,height,pixsz)) /* allocate new subraster */
==   (subraster *)NULL ) goto end_of_job; /* failed, so quit */
/* --- initialize subraster parameters --- */
sp->type = IMAGERASTER;			/* image */
sp->baseline = base;			/* composite baseline */
sp->size = sp1->size;			/* underlying char is sp1 */
/* --- extract raster from subraster --- */
rp = sp->image;				/* raster allocated in subraster */
/* -------------------------------------------------------------------------
overlay sp1 and sp2 in new composite raster
-------------------------------------------------------------------------- */
if ( isalign )
  { rastput (rp, sp1->image, base-base1, (width-width1)/2, 1);	/*underlying*/
    rastput (rp, sp2->image, base-base2,			/*overlaid*/
		(width-width2)/2+offset2, 0); }
else
  { rastput (rp, sp1->image, base-base1, (width-width1)/2, 1);	/*underlying*/
    rastput (rp, sp2->image, (height-height2)/2,		/*overlaid*/
		(width-width2)/2+offset2, 0); }
/* -------------------------------------------------------------------------
free input if requested
-------------------------------------------------------------------------- */
if ( isfree > 0 )			/* caller wants input freed */
  { if ( isfree==1 || isfree>2 ) delete_subraster(sp1);	/* free sp1 */
    if ( isfree >= 2 ) delete_subraster(sp2); }		/* and/or sp2 */
/* -------------------------------------------------------------------------
Back to caller with pointer to concatted subraster or with null for error
-------------------------------------------------------------------------- */
end_of_job:
  return ( sp );			/* back with subraster or null ptr */
} /* --- end-of-function rastcompose() --- */


/* ==========================================================================
 * Function:	rastcat ( sp1, sp2, isfree )
 * Purpose:	"Concatanates" subrasters sp1||sp2, leaving both unchanged
 *		and returning a newly-allocated subraster.
 *		Frees/deletes input sp1 and/or sp2 depending on value
 *		of isfree (0=none, 1=sp1, 2=sp2, 3=both).
 * --------------------------------------------------------------------------
 * Arguments:	sp1 (I)		subraster *  to left-hand subraster
 *		sp2 (I)		subraster *  to right-hand subraster
 *		isfree (I)	int containing 1=free sp1 before return,
 *				2=free sp2, 3=free both, 0=free none.
 * --------------------------------------------------------------------------
 * Returns:	( subraster * )	pointer to constructed subraster sp1||sp2
 *				or  NULL for any error
 * --------------------------------------------------------------------------
 * Notes:
 * ======================================================================= */
/* --- entry point --- */
subraster *rastcat ( subraster *sp1, subraster *sp2, int isfree )
{
/* -------------------------------------------------------------------------
Allocations and Declarations
-------------------------------------------------------------------------- */
subraster *new_subraster(), *sp=(subraster *)NULL; /* returned subraster */
raster	*rp=(raster *)NULL;		/* new concatted raster */
int	delete_subraster();		/* in case isfree non-zero */
int	rastput();			/*place sp1,sp2 in concatted raster*/
int	type_raster();			/* debugging display */
int	base1   = sp1->baseline,	/*baseline for left-hand subraster*/
	height1 = (sp1->image)->height,	/* height for left-hand subraster */
	width1  = (sp1->image)->width,	/* width for left-hand subraster */
	pixsz1  = (sp1->image)->pixsz,	/* pixsz for left-hand subraster */
	type1   = sp1->type,		/* image type for left-hand */
	base2   = sp2->baseline,	/*baseline for right-hand subraster*/
	height2 = (sp2->image)->height,	/* height for right-hand subraster */
	width2  = (sp2->image)->width,	/* width for right-hand subraster */
	pixsz2  = (sp2->image)->pixsz,	/* pixsz for right-hand subraster */
	type2   = sp2->type;		/* image type for right-hand */
int	height=0, width=0, pixsz=0, base=0; /*concatted sp1||sp2 composite*/
int	issmash = (smashmargin!=0?1:0),	/* true to "squash" sp1||sp2 */
	isopaque = (issmash?0:1),	/* not oppaque if smashing */
	rastsmash(), isblank=0, nsmash=0, /* #cols to smash */
	oldsmashmargin = smashmargin;	/* save original smashmargin */
mathchardef *symdef1 = sp1->symdef,	/*mathchardef of last left-hand char*/
	*symdef2 = sp2->symdef;		/* mathchardef of right-hand char */
int	class1 = (symdef1==NULL?ORDINARY:symdef1->class), /* symdef->class */
	class2 = (symdef2==NULL?ORDINARY:symdef2->class), /* or default */
	smash1 = (symdef1!=NULL)&&(class1==ORDINARY||class1==VARIABLE||
		  class1==OPENING||class1==CLOSING||class1==PUNCTION),
	smash2 = (symdef2!=NULL)&&(class2==ORDINARY||class2==VARIABLE||
		  class2==OPENING||class2==CLOSING||class2==PUNCTION),
	space = fontsize/2+1;		/* #cols between sp1 and sp2 */
/* -------------------------------------------------------------------------
Initialization
-------------------------------------------------------------------------- */
/* --- determine inter-character space from character class --- */
if ( !isstring )
  space = max2(2,(symspace[class1][class2] + fontsize-3)); /* space */
else space = 1;				/* space for ascii string */
if ( !iscatspace ) space=0;		/* spacing explicitly turned off */
/* --- determine smash --- */
if ( !isstring )			/* don't smash strings */
 if ( issmash ) {			/* raster smash wanted */
   int	maxsmash = rastsmash(sp1,sp2),	/* calculate max smash space */
	margin = smashmargin;		/* init margin without delta */
   if ( (1 && smash1 && smash2)		/* concatanating two chars */
   ||   (1 && type1!=IMAGERASTER && type2!=IMAGERASTER) )
     /*maxsmash = 0;*/			/* turn off smash */
     margin = max2(space-1,0);		/* force small smashmargin */
   else					/* adjust for delta if images */
     if ( issmashdelta )		/* smashmargin is a delta value */
       margin += fontsize;		/* add displaystyle base to margin */
   if ( maxsmash == blanksignal )	/* sp2 is intentional blank */
     isblank = 1;			/* set blank flag signal */
   else					/* see how much extra space we have*/
     if ( maxsmash > margin )		/* enough space for adjustment */
       nsmash = maxsmash-margin;	/* make adjustment */
   if ( msgfp!=NULL && msglevel>=99 )	/* display smash results */
     { fprintf(msgfp,"rastcat> maxsmash=%d, margin=%d, nsmash=%d\n",
       maxsmash,margin,nsmash);
       fprin