path: root/Build/source/texk/dvipng/special.c

/* special.c */

/************************************************************************

  Part of the dvipng distribution

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this program. If not, see
  <http://www.gnu.org/licenses/>.

  Copyright (C) 2002-2009 Jan-Åke Larsson

************************************************************************/

#include "dvipng.h"

#define SKIPSPACES(s) while(s && *s==' ' && *s!='\0') s++

/* PostScript can come as a string (headers and raw specials) or 
   a memory-mapped file (headers and included EPS figures). */

struct pscode {
  struct pscode*  next;
  char*           special;  /* complete special */
  char*           code;     /* PS string, null if a file */
  char*           filename; /* file name, null if a string */
  char*           postcode; /* post PS string */
  struct filemmap fmmap;    /* file mmap */
};

struct pscode* psheaderp=NULL; /* static, DVI-specific header list */

static void PSCodeInit(struct pscode *entry, char *special)
{
  entry->next=NULL;
  entry->special=special;
  entry->code=NULL;
  entry->filename=NULL;
  entry->postcode=NULL;
  entry->fmmap.data=NULL;
  if (special==NULL)
    return;
  if (strncmp(special,"header=",7)==0)
    entry->filename=special+7;
  else if (strncmp(special,"ps:: plotfile ",14)==0)
    entry->filename=special+14;
  else if (special[0]=='"' || special[0]=='!')
    entry->code=special+1;
  else if (strncmp(special,"ps::[begin]",11)==0)
    entry->code=special+11;
  else if (strncmp(special,"ps::[end]",9)==0)
    entry->code=special+9;
  else if (strncmp(special,"ps::",4)==0)
    entry->code=special+4;
  else if (strncmp(special,"ps:",3)==0)
    entry->code=special+3;
  else
    entry->code=special;
#ifdef DEBUG
  if (entry->code!=NULL)
    DEBUG_PRINT(DEBUG_GS,(" '%s'",entry->code));
  if (entry->filename!=NULL)
    DEBUG_PRINT(DEBUG_GS,(" {%s}",entry->filename));
  if (entry->postcode!=NULL)
    DEBUG_PRINT(DEBUG_GS,(" '%s'",entry->postcode));
#endif
}



void ClearPSHeaders(void)
{
  struct pscode *temp=psheaderp;

  while(temp!=NULL) {
    psheaderp=psheaderp->next;
    if (temp->fmmap.data!=NULL)
      UnMmapFile(&(temp->fmmap));
    free(temp);
    temp=psheaderp;
  }
}

static void writepscode(struct pscode* pscodep, FILE* psstream)
{
  while (pscodep!=NULL) {
    if (pscodep->code!=NULL) {
      fputs(pscodep->code,psstream);
      putc('\n',psstream);
      DEBUG_PRINT(DEBUG_GS,("\n  PS CODE:\t%s",pscodep->code));
    }
    if (pscodep->filename!=NULL && pscodep->fmmap.data==NULL) {
      char* filepath=
	kpse_find_file(pscodep->filename,kpse_tex_ps_header_format,false);
      if (filepath==NULL) {
	Warning("Cannot find PostScript file %s, ignored", pscodep->filename);
	page_flags |= PAGE_GAVE_WARN;
      } else if (MmapFile(filepath,&(pscodep->fmmap))) {
	Warning("PostScript file %s unusable, ignored", pscodep->filename);
	page_flags |= PAGE_GAVE_WARN;
      }
    }
    if (pscodep->fmmap.data!=NULL) {
      unsigned char* position;

      DEBUG_PRINT(DEBUG_GS,("\n  PS FILE:\t%s",pscodep->filename));
      position=(unsigned char*)pscodep->fmmap.data;
      while(position 
	    < (unsigned char*)pscodep->fmmap.data + pscodep->fmmap.size) {
	putc(*position,psstream);
	position++;
      }
    }
    if (pscodep->postcode!=NULL) {
      fputs(pscodep->postcode,psstream);
      putc('\n',psstream);
      DEBUG_PRINT(DEBUG_GS,("\n  PS POST CODE:\t%s",pscodep->postcode));
    }
    pscodep=pscodep->next;
  }
}


static gdImagePtr
ps2png(struct pscode* pscodep, char *device, int hresolution, int vresolution, 
       int llx, int lly, int urx, int ury, int bgred, int bggreen, int bgblue)
{
#ifndef MIKTEX
  int downpipe[2], uppipe[2];
  pid_t pid;
#else
  HANDLE hPngStream;
  HANDLE hPsStream;
  HANDLE hStdErr;
  PROCESS_INFORMATION pi;
  _TCHAR szCommandLine[2048];
  _TCHAR szGsPath[_MAX_PATH];
#define GS_PATH szGsPath
  int fd;
#endif
  FILE *psstream=NULL, *pngstream=NULL;
  char resolution[STRSIZE]; 
  /*   char devicesize[STRSIZE];  */
  gdImagePtr psimage=NULL;
  static bool showpage=false;

  sprintf(resolution, "-r%dx%d",hresolution,vresolution);
  /* Future extension for \rotatebox
  status=sprintf(devicesize, "-g%dx%d",
		 //(int)((sin(atan(1.0))+1)*
		 (urx - llx)*hresolution/72,//), 
		 //(int)((sin(atan(1.0))+1)*
		 (ury - lly)*vresolution/72);//);
  */
  DEBUG_PRINT(DEBUG_GS,
	      ("\n  GS CALL:\t%s %s %s %s %s %s %s %s %s %s %s",/* %s", */
	       GS_PATH, device, resolution, /*devicesize,*/
	       "-dBATCH", "-dNOPAUSE", "-q", "-sOutputFile=-", 
	       "-dTextAlphaBits=4", "-dGraphicsAlphaBits=4",
	       (option_flags & NO_GSSAFER) ? "-": "-dSAFER", 
	       (option_flags & NO_GSSAFER) ? "": "- "));
#ifndef MIKTEX
  if (pipe(downpipe) || pipe(uppipe)) return(NULL);
  /* Ready to fork */
  pid = fork ();
  if (pid == 0) { /* Child process.  Execute gs. */       
    close(downpipe[1]);
    dup2(downpipe[0], STDIN_FILENO);
    close(downpipe[0]);
    close(uppipe[0]);
    dup2(uppipe[1], STDOUT_FILENO);
    close(uppipe[1]);
    execlp(GS_PATH, GS_PATH, device, resolution, /*devicesize,*/
	   "-dBATCH", "-dNOPAUSE", "-q", "-sOutputFile=-", 
	   "-dTextAlphaBits=4", "-dGraphicsAlphaBits=4",
	   (option_flags & NO_GSSAFER) ? "-": "-dSAFER", 
	   (option_flags & NO_GSSAFER) ? NULL: "-",
	   NULL);
    _exit (EXIT_FAILURE);
  }
  /* Parent process. */
  
  close(downpipe[0]);
  psstream=fdopen(downpipe[1],"wb");
  /* fclose(psstream);  psstream=fopen("test.ps","wb"); */
  if (psstream == NULL) 
    close(downpipe[1]);
  close(uppipe[1]);
  pngstream=fdopen(uppipe[0],"rb");
  if (pngstream == NULL) 
    close(uppipe[0]);
#else /* MIKTEX */
  if (! miktex_find_miktex_executable("mgs.exe", szGsPath)) {
      Warning("Ghostscript could not be found");
      return(NULL);
  }
  sprintf(szCommandLine,"\"%s\" %s %s %s %s %s %s %s %s %s %s",/* %s",*/
	  szGsPath, device, resolution, /*devicesize,*/
	  "-dBATCH", "-dNOPAUSE", "-q", "-sOutputFile=-", 
	  "-dTextAlphaBits=4", "-dGraphicsAlphaBits=4",
	  (option_flags & NO_GSSAFER) ? "-": "-dSAFER", 
	  (option_flags & NO_GSSAFER) ? "": "-");
  if (! miktex_start_process_3(szCommandLine, &pi, INVALID_HANDLE_VALUE,
			       &hPsStream, &hPngStream, &hStdErr, 0)) {
      Warning("Ghostscript could not be started");
      return(NULL);
  }
  CloseHandle (pi.hThread);
  fd = _open_osfhandle((intptr_t)hPsStream, _O_WRONLY);
  if (fd >= 0) { 
    psstream = _tfdopen(fd, "wb");
    if (psstream == NULL) 
      _close (fd);
  }
  fd = _open_osfhandle((intptr_t)hPngStream, _O_RDONLY);
  if (fd >= 0) {
    pngstream = _tfdopen(fd, "rb");
    if (pngstream == NULL) 
      _close (fd);
  }
#endif 
  if (psstream) {
    writepscode(psheaderp,psstream);
    DEBUG_PRINT(DEBUG_GS,("\n  PS CODE:\t<</PageSize[%d %d]/PageOffset[%d %d[1 1 dtransform exch]{0 ge{neg}if exch}forall]>>setpagedevice",
			  urx - llx, ury - lly,llx,lly));
    fprintf(psstream, "<</PageSize[%d %d]/PageOffset[%d %d[1 1 dtransform exch]{0 ge{neg}if exch}forall]>>setpagedevice\n",
	    urx - llx, ury - lly,llx,lly);
    if ( bgred < 255 || bggreen < 255 || bgblue < 255 ) {
      DEBUG_PRINT(DEBUG_GS,("\n  PS CODE:\tgsave %f %f %f setrgbcolor clippath fill grestore",
			    bgred/255.0, bggreen/255.0, bgblue/255.0));
      fprintf(psstream, "gsave %f %f %f setrgbcolor clippath fill grestore",
	      bgred/255.0, bggreen/255.0, bgblue/255.0);
    }
    writepscode(pscodep,psstream);
    if (showpage) {
      DEBUG_PRINT(DEBUG_GS,("\n  PS CODE:\tshowpage"));
      fprintf(psstream, " showpage ");
    }
    fclose(psstream);
  }
  if (pngstream) {
    psimage = gdImageCreateFromPng(pngstream);
    fclose(pngstream);
  }
#ifdef MIKTEX
  CloseHandle(pi.hProcess);
#endif
  if (psimage == NULL) {
    DEBUG_PRINT(DEBUG_GS,("\n  GS OUTPUT:\tNO IMAGE "));
    if (!showpage) {
      showpage=true;
      DEBUG_PRINT(DEBUG_GS,("(will try adding \"showpage\") "));
      psimage=ps2png(pscodep,
		     device, hresolution, vresolution, llx, lly, urx, ury,
		     bgred,bggreen,bgblue);
      showpage=false;
    }
#ifdef DEBUG
  } else {
    DEBUG_PRINT(DEBUG_GS,("\n  GS OUTPUT:\t%dx%d image ",
			  gdImageSX(psimage),gdImageSY(psimage)));
#endif
  }
  return psimage;
}

static gdImagePtr
rescale(gdImagePtr psimage, int pngwidth, int pngheight)
{
  gdImagePtr scaledimage=psimage;
  /* Rescale unless correct size */
  if (psimage!=NULL
      && gdImageSX(psimage)!=pngwidth 
      && gdImageSY(psimage)!=pngheight) {
    DEBUG_PRINT(DEBUG_DVI,
		("\n  RESCALE INCLUDED BITMAP \t(%d,%d) -> (%d,%d)",
		 gdImageSX(psimage),gdImageSY(psimage),
		 pngwidth,pngheight));
#ifdef HAVE_GDIMAGECREATETRUECOLOR
    scaledimage=gdImageCreateTrueColor(pngwidth,pngheight);
    /* Copy with overwrite, remember that this is the rescaled source
       image. The real target has alpha blending on. */
    gdImageAlphaBlending(scaledimage,0);
    gdImageCopyResampled(scaledimage,psimage,0,0,0,0,
			 pngwidth,pngheight,
			 gdImageSX(psimage),gdImageSY(psimage));
#else
    scaledimage=gdImageCreate(pngwidth,pngheight);
    gdImageCopyResized(scaledimage,psimage,0,0,0,0,
		       pngwidth,pngheight,
		       gdImageSX(psimage),gdImageSY(psimage));
#endif
    gdImageDestroy(psimage);
  }
  return(scaledimage);
}

static void newpsheader(char* special) {
  struct pscode* tmp;
  char* txt;

  if (psheaderp==NULL && strcmp(special,"header=tex.pro")!=0) {
    newpsheader("header=tex.pro");
    newpsheader("header=color.pro");
    newpsheader("header=special.pro");
  }
  if (strcmp(special+strlen(special)-4,".xcp")==0
      && strncmp(special,"header=",7)==0) 
    InitXColorPrologue(special+7);
  if (strncmp(special,"! /pgfH",7)==0)
    newpsheader("! TeXDict begin");
  if (psheaderp==NULL) {
    if ((tmp=psheaderp=malloc(sizeof(struct pscode)))==NULL)
      Fatal("cannot allocate space for PostScript header struct");
  } else {
    /* No duplicates. This still misses pre=..., because we still
       change that. To be fixed */
    tmp=psheaderp;
    if (strcmp(tmp->special,special)==0)
      return;
    while(tmp->next!=NULL) {
      tmp=tmp->next;
      if (strcmp(tmp->special,special)==0)
	return;
    }
    if ((tmp->next=malloc(sizeof(struct pscode)))==NULL)
      Fatal("cannot allocate space for PostScript header struct");
    tmp=tmp->next;
  }
  DEBUG_PRINT(DEBUG_GS,("\n  PS HEADER "));
  if ((txt=malloc(strlen(special)+1))==NULL)
    Fatal("cannot malloc space for PostScript header");
  strcpy(txt,special);
  PSCodeInit(tmp,txt);
}

/*********************************************************************/
/****************************  SetSpecial  ***************************/
/*********************************************************************/

void SetSpecial(char * special, int32_t hh, int32_t vv)
/* interpret a \special command, made up of keyword=value pairs,
 * or !header or ps:literal_PostScript
 */
{
  DEBUG_PRINT(DEBUG_DVI,(" '%s'",special));
  SKIPSPACES(special);
  /********************** Color specials ***********************/
  if (strncmp(special,"background ",11)==0) {
    background(special+11);
    return;
  }
  if (strncmp(special,"color ",6)==0) {
    special+=6;
    SKIPSPACES(special);
    if (strncmp(special,"push ",5)==0) {
      pushcolor(special+5);
    } else {
      if (strcmp(special,"pop")==0)
	popcolor();
      else 
	resetcolorstack(special);
    }
    return;
  }

  /******************* Image inclusion ********************/

  /* Needed tests for regression: PNG, GIF, JPEG and EPS inclusion,
   * for different gd versions */

  if (strncmp(special,"PSfile=",7)==0) { /* PSfile */
    char* psname = special+7;
    int llx=0,lly=0,urx=0,ury=0,rwi=0,rhi=0;
    bool clip=false;
    int hresolution,vresolution;
    int pngheight,pngwidth;

    /* Remove quotation marks around filename. If no quotation marks,
       use first word as filename */
    if (*psname=='"') {
      psname++;
      special=strrchr(psname,'"');
    } else {
      special=strchr(psname,' ');
    }
    if (special!=NULL) {
      *special='\0';
      special++;
    }
    
    /* Retrieve parameters */
    SKIPSPACES(special);
    while(special && *special) {
      if (strncmp(special,"llx=",4)==0)
	llx = strtol(special+4,&special,10);
      else if (strncmp(special,"lly=",4)==0)
	lly = strtol(special+4,&special,10);
      else if (strncmp(special,"urx=",4)==0)
	urx = strtol(special+4,&special,10);
      else if (strncmp(special,"ury=",4)==0)
	ury = strtol(special+4,&special,10);
      else if (strncmp(special,"rwi=",4)==0)
	rwi = strtol(special+4,&special,10);
      else if (strncmp(special,"rhi=",4)==0)
	rhi = strtol(special+4,&special,10);
      else if (strncmp(special,"clip",4)==0)
	{clip = true; special=special+4;}
      while (*special && *special!=' ') special++;
      SKIPSPACES(special);
    }
    
    /* Calculate resolution, and use our base resolution as a fallback. */
    /* The factor 10 is magic, the dvips graphicx driver needs this.    */
    hresolution = ((dpi*rwi+urx-llx-1)/(urx - llx)+9)/10;
    vresolution = ((dpi*rhi+ury-lly-1)/(ury - lly)+9)/10;
    if (vresolution==0) vresolution = hresolution;
    if (hresolution==0) hresolution = vresolution;
    if (hresolution==0) hresolution = vresolution = dpi;
      
    /* Convert from postscript 72 dpi resolution to our given resolution */
    pngwidth  = (dpi*rwi+719)/720; /* +719: round up */
    pngheight = (dpi*rhi+719)/720;
    if (pngwidth==0)  
      pngwidth  = ((dpi*rhi*(urx-llx)+ury-lly-1)/(ury-lly)+719)/720;
    if (pngheight==0) 
      pngheight = ((dpi*rwi*(ury-lly)+urx-llx-1)/(urx-llx)+719)/720;
    if (pngheight==0) {
      pngwidth  = (dpi*(urx-llx)+71)/72;
      pngheight = (dpi*(ury-lly)+71)/72;
    }    
    if (page_imagep != NULL) { /* Draw into image */
      struct pscode image;
      gdImagePtr psimage=NULL;
#ifndef HAVE_GDIMAGECREATEFROMPNGPTR
      FILE* psstream;
#endif

      PSCodeInit(&image, NULL);
      TEMPSTR(image.filename,kpse_find_file(psname,kpse_pict_format,0));
      if (MmapFile(image.filename,&(image.fmmap)) || image.fmmap.size==0) {
	Warning("Image file %s unusable, image will be left blank",
		image.filename);
	page_flags |= PAGE_GAVE_WARN;
	return;
      } 
      Message(BE_NONQUIET," <%s",psname);
      switch ((unsigned char)*image.fmmap.data) {
      case 0x89: /* PNG magic: "\211PNG\r\n\032\n" */
	DEBUG_PRINT(DEBUG_DVI,("\n  INCLUDE PNG \t%s",image.filename));
#ifdef HAVE_GDIMAGECREATEFROMPNGPTR
	psimage=gdImageCreateFromPngPtr(image.fmmap.size,image.fmmap.data);
#else
	psstream=fopen(image.filename,"rb");
	psimage=gdImageCreateFromPng(psstream);
	fclose(psstream);
#endif
	psimage=rescale(psimage,pngwidth,pngheight);
	break;
      case 'G': /* GIF magic: "GIF87" or "GIF89" */
	DEBUG_PRINT(DEBUG_DVI,("\n  INCLUDE GIF \t%s",image.filename));
#ifdef HAVE_GDIMAGEGIF
	psimage=rescale(gdImageCreateFromGifPtr(image.fmmap.size,
						image.fmmap.data),
			pngwidth,pngheight);
#else
	DEBUG_PRINT(DEBUG_DVI,(" (NO GIF DECODER)"));
#endif
	break;
      case 0xff: /* JPEG magic: 0xffd8 */
	DEBUG_PRINT(DEBUG_DVI,("\n  INCLUDE JPEG \t%s",image.filename));
#ifdef HAVE_GDIMAGECREATEFROMJPEG
#ifdef HAVE_GDIMAGECREATEFROMPNGPTR
	psimage=gdImageCreateFromJpegPtr(image.fmmap.size,image.fmmap.data);
#else
	psstream=fopen(image.filename,"rb");
	psimage=gdImageCreateFromJpeg(psstream);
	fclose(psstream);
#endif
	psimage=rescale(psimage,pngwidth,pngheight);
#else
	DEBUG_PRINT(DEBUG_DVI,(" (NO JPEG DECODER)"));
#endif
	break;
      default:  /* Default, PostScript magic: "%!PS-Adobe" */
	if (option_flags & NO_GHOSTSCRIPT) {
	  Warning("GhostScript calls disallowed by --noghostscript" );
	  page_flags |= PAGE_GAVE_WARN;
	} else {
	  /* Use alpha blending, and render transparent postscript
	     images. The alpha blending works correctly only from
	     libgd 2.0.12 upwards */
#ifdef HAVE_GDIMAGEPNGEX
	  if (page_imagep->trueColor) {
	    int tllx=llx,tlly=lly,turx=urx,tury=ury;

	    DEBUG_PRINT((DEBUG_DVI | DEBUG_GS),
			("\n  GS RENDER \t%s -> pngalpha ",image.filename));
	    if (!clip) {
	      /* Render across the whole image */ 
	      tllx=llx-(hh+1)*72/hresolution;
	      tlly=lly-(gdImageSY(page_imagep)-vv-1)*72/vresolution;
	      turx=llx+(gdImageSX(page_imagep)-hh)*72/hresolution;
	      tury=lly+(vv+1)*72/vresolution;
	      DEBUG_PRINT((DEBUG_DVI | DEBUG_GS),
			  ("\n  EXPAND BBOX \t%d %d %d %d -> %d %d %d %d",
			   llx,lly,urx,ury,tllx,tlly,turx,tury));
#ifdef DEBUG
	    } else {
	      DEBUG_PRINT((DEBUG_DVI | DEBUG_GS),(", CLIPPED TO BBOX"));
#endif
	    }
	    psimage = ps2png(&image, "-sDEVICE=pngalpha", 
			     hresolution, vresolution, 
			     tllx, tlly, turx, tury,
			     255,255,255);
	    if (psimage==NULL)
	      Warning("No GhostScript pngalpha output, opaque image inclusion");
	  } else
	    Warning("Palette output, opaque image inclusion");
#endif
	  if (psimage==NULL) {
	    /* png256 gives inferior result */
	    DEBUG_PRINT((DEBUG_DVI | DEBUG_GS),
			("\n  GS RENDER \t%s -> png16m", image.filename));
	    psimage = ps2png(&image, "-sDEVICE=png16m",
			     hresolution, vresolution, 
			     llx, lly, urx, ury,
			     cstack[0].red,cstack[0].green,cstack[0].blue);
	    clip=true;
	    page_flags |= PAGE_GAVE_WARN;
	  }
	  if (!clip) {
	    /* Rendering across the whole image */
	    hh=0;
	    vv=gdImageSY(psimage)-1;
	  }
	}
      }
      UnMmapFile(&(image.fmmap));
      if (psimage!=NULL) {
	DEBUG_PRINT(DEBUG_DVI,
		    ("\n  GRAPHIC(X|S) INCLUDE \t%s (%d,%d) res %dx%d at (%d,%d)",
		     psname,gdImageSX(psimage),gdImageSY(psimage),
		     hresolution,vresolution,hh,vv));
#ifdef HAVE_GDIMAGECREATETRUECOLOR
	if (psimage->trueColor && !page_imagep->trueColor)
	  gdImageTrueColorToPalette(psimage,0,256);
#endif
#ifdef HAVE_GDIMAGEPNGEX
	gdImageAlphaBlending(page_imagep,1);
#else
	Warning("Using libgd < 2.0.12, opaque image inclusion");
	page_flags |= PAGE_GAVE_WARN;
#endif
	gdImageCopy(page_imagep, psimage, 
		    hh, vv-gdImageSY(psimage)+1,
		    0,0,
		    gdImageSX(psimage),gdImageSY(psimage));
#ifdef HAVE_GDIMAGEPNGEX
	gdImageAlphaBlending(page_imagep,0);
#endif
	gdImageDestroy(psimage);
      } else {
        Warning("Unable to load %s, image will be left blank",image.filename);
        page_flags |= PAGE_GAVE_WARN;
      } 
      Message(BE_NONQUIET,">");
    } else { /* Don't draw */
      page_flags |= PAGE_TRUECOLOR;
      DEBUG_PRINT(DEBUG_DVI,
		  ("\n  GRAPHIC(X|S) INCLUDE \t%s (%d,%d) res %dx%d at (%d,%d)",
		   psname,pngheight,pngwidth,
		   hresolution,vresolution,hh,vv));
      min(x_min,hh);
      min(y_min,vv-pngheight+1);
      max(x_max,hh+pngwidth);
      max(y_max,vv+1);
    }
    return;
  }

  /******************* Raw PostScript ********************/

  if (strncmp(special,"!/preview@version(",18)==0) { 
    int length=0;
    special+=18;
    while (special[length]!='\0' && special[length]!=')') 
      length++;
    if (page_imagep==NULL) 
      Message(BE_NONQUIET," (preview-latex version %.*s)",length,special);
    return;
  }

  /* preview-latex' tightpage option */
  if (strncmp(special,"!/preview@tightpage",19)==0) { 
    special+=19;
    SKIPSPACES(special);
    if (strncmp(special,"true",4)==0) {
      if (page_imagep==NULL) 
	Message(BE_NONQUIET," (preview-latex tightpage option detected, will use its bounding box)");
      dvi->flags |= DVI_PREVIEW_LATEX_TIGHTPAGE;
    }
    return;
  }
  if (strncmp(special,"!userdict",9)==0 
      && strstr(special+10,"7{currentfile token not{stop}if 65781.76 div")!=NULL) {
    if (page_imagep==NULL && ~dvi->flags & DVI_PREVIEW_LATEX_TIGHTPAGE) 
      Message(BE_NONQUIET," (preview-latex <= 0.9.1 tightpage option detected, will use its bounding box)");
    dvi->flags |= DVI_PREVIEW_LATEX_TIGHTPAGE;
    return;
  }

  /* preview-latex' dvips bop-hook redefinition */
  if (strncmp(special,"!userdict",9)==0 
      && strstr(special+10,"preview-bop-")!=NULL) {
    dvi->flags |= DVI_PREVIEW_BOP_HOOK;
    if (page_imagep==NULL) 
      Message(BE_VERBOSE," (preview-latex beginning-of-page-hook detected)");
    return;
  }

  if (dvi->flags & DVI_PREVIEW_BOP_HOOK && ~page_flags & PAGE_PREVIEW_BOP 
      && strncmp(special,"ps::",4)==0) {
    dviunits adj_llx,adj_lly,adj_urx,adj_ury,ht,dp,wd;
    page_flags |= PAGE_PREVIEW_BOP;
    /* Hokay, decode bounding box */
    adj_llx = strtol(special+4,&special,10);
    adj_lly = strtol(special,&special,10);
    adj_urx = strtol(special,&special,10);
    adj_ury = strtol(special,&special,10);
    ht = strtol(special,&special,10);
    dp = strtol(special,&special,10);
    wd = strtol(special,&special,10);
    if (wd>0) {
      x_offset_tightpage = 
	(-adj_llx+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor;
      x_width_tightpage  = x_offset_tightpage
	+(wd+adj_urx+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor;
    } else {
      x_offset_tightpage = 
	(-wd+adj_urx+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor;
      x_width_tightpage  = x_offset_tightpage
	+(-adj_llx+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor;
    }
    /* y-offset = height - 1 */
    y_offset_tightpage = 
      (((ht>0)?ht:0)+adj_ury+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor-1;
    y_width_tightpage  = y_offset_tightpage+1
      +(((dp>0)?dp:0)-adj_lly+dvi->conv*shrinkfactor-1)/dvi->conv/shrinkfactor;
    return;
  }

  if (special[0]=='"' || strncmp(special,"ps:",3)==0) { /* Literal PostScript */
    if (page_imagep != NULL) { /* Draw into image */
      static struct pscode *pscodep=NULL;
      static bool psenvironment=false;
      bool nextisps;
      struct pscode *tmp;
      gdImagePtr psimage=NULL;
      char *txt;
      
      /* Some packages split their literal PostScript code into
	 several specials. Check for those, and concatenate them so
	 that they're given to one and the same invocation of gs */
      if (pscodep==NULL) {
	Message(BE_NONQUIET," <literal PS");
	if ((tmp=pscodep=malloc(sizeof(struct pscode)))==NULL)
	  Fatal("cannot allocate space for raw PostScript struct");
      } else {
	tmp=pscodep;
	while(tmp->next != NULL)
	  tmp=tmp->next;
	if ((tmp->next=malloc(sizeof(struct pscode)))==NULL)
	  Fatal("cannot allocate space for raw PostScript struct");
	tmp=tmp->next;
      }
      if (strncmp(special,"ps::[begin]",11)==0)
	psenvironment=true;
      else if (strncmp(special,"ps::[end]",9)==0)
	psenvironment=false;
      else if (strcmp(special,"ps:: pgfo")==0)
	/* PostScript code to start page for pgf PostScript
	   specials. The first numbers are generally valid for the bop
	   instruction, and the latter code is to move the origin to
	   the right place. */
	special="ps:: 39139632 55387786 1000 600 600 (tikzdefault.dvi) @start 1 0 bop pgfo 0 0 matrix defaultmatrix transform itransform translate";
      else if (strcmp(special,"ps:: pgfc")==0)
	special="ps:: pgfc eop end";
      nextisps=DVIIsNextPSSpecial(dvi);
      if (psenvironment || nextisps) {
	if (!nextisps) {
	  Warning("PostScript environment contains DVI commands");
	  page_flags |= PAGE_GAVE_WARN;
	}
	/* Don't use alloca, we do not want to run out of stack space */
	DEBUG_PRINT(DEBUG_GS,("\n  PS SPECIAL "));
	txt=malloc(strlen(special)+1);
	strcpy(txt,special);
	PSCodeInit(tmp,txt);
	return;
      }
      DEBUG_PRINT(DEBUG_DVI,("\n  LAST PS SPECIAL "));
      PSCodeInit(tmp,special);
      /* Now, render image */
      if (option_flags & NO_GHOSTSCRIPT)
	Warning("GhostScript calls disallowed by --noghostscript" );
      else {
	/* Use alpha blending, and render transparent postscript
	   images. The alpha blending works correctly only from
	   libgd 2.0.12 upwards */
#ifdef HAVE_GDIMAGEPNGEX
	if (page_imagep->trueColor) {
	  /* Render across the whole image */ 
	  psimage = ps2png(pscodep, "-sDEVICE=pngalpha", 
			   dpi,dpi, 
			   -(hh+1)*72/dpi,
			   -(gdImageSY(page_imagep)-vv-1)*72/dpi,
			   (gdImageSX(page_imagep)-hh)*72/dpi,
			   (vv+1)*72/dpi,
			   255,255,255);
	  if (psimage!=NULL) {
	    gdImageAlphaBlending(page_imagep,1);
	    gdImageCopy(page_imagep, psimage, 
			0,0,0,0,
			gdImageSX(psimage),gdImageSY(psimage));
	    gdImageAlphaBlending(page_imagep,0);
	    gdImageDestroy(psimage);
	  } else
	    Warning("No GhostScript pngalpha output, cannot render raw PostScript");
	} else
	  Warning("Palette output, cannot include raw PostScript");
#else
	Warning("Using libgd < 2.0.12, unable to include raw PostScript");
#endif
      }
      while(pscodep->next != NULL) {
	tmp=pscodep->next;
	free(pscodep->special);
	free(pscodep);
	pscodep=tmp;
      }
      free(pscodep);
      pscodep=NULL;
      if (psimage==NULL) 
	page_flags |= PAGE_GAVE_WARN;
      Message(BE_NONQUIET,">");
    } else { /* Don't draw */
      page_flags |= PAGE_TRUECOLOR;
    }
    return;
  }

  if (strncmp(special,"papersize=",10)==0) { /* papersize spec, ignored */
    return;
  }

  if (special[0]=='!' || strncmp(special,"header=",7)==0) { /* PS header */
    newpsheader(special);
    return;
  }

  if (strncmp(special,"src:",4)==0) { /* source special */
    if ( page_imagep != NULL )
      Message(BE_NONQUIET," at (%ld,%ld) source \\special{%s}",
	      hh, vv, special);
    return;
  }
  if ( page_imagep != NULL ) {
    Warning("at (%ld,%ld) unimplemented \\special{%s}",
	    hh, vv, special);
    page_flags |= PAGE_GAVE_WARN;
  }
}