/*
 * TransFig: Facility for Translating Fig code
 * Copyright (c) 1992 by Brian Boyter
 * Parts Copyright (c) 1989-2002 by Brian V. Smith
 *
 * Any party obtaining a copy of these files is granted, free of charge, a
 * full and unrestricted irrevocable, world-wide, paid up, royalty-free,
 * nonexclusive right and license to deal in this software and
 * documentation files (the "Software"), including without limitation the
 * rights to use, copy, modify, merge, publish and/or distribute copies of
 * the Software, and to permit persons who receive copies from any such 
 * party to do so, with the only requirement being that this copyright 
 * notice remain intact.
 *
 */

#include "fig2dev.h"
#include "object.h"

int	_read_pcx();
void	readpcxhead();

/* return codes:  1 : success
		  0 : invalid file
*/

int
read_pcx(file,filetype,pic,llx,lly)
    FILE	   *file;
    int		    filetype;
    F_pic	   *pic;
    int		   *llx, *lly;
{
	*llx = *lly = 0;
	pic->transp = -1;
	return _read_pcx(file, pic);
}

/* pcx2ppm 1.2 - convert pcx to ppm
 * based on zgv's readpcx.c
 * public domain by RJM
 *
 * this is incredibly messy
 *
 * 1999-03-16	updated to support 24-bit.
 */

typedef unsigned char byte;

struct pcxhed
  {
  byte manuf,ver,encod,bpp;		/* 0 - 3 gen format */
  byte x1lo,x1hi,y1lo,y1hi;		/* 4 - 11 size */
  byte x2lo,x2hi,y2lo,y2hi;
  byte unused1[4];			/* 12 - 15 scrn size */
  byte pal16[48];			/* 16 - 63 4-bit palette */
  byte reserved;			/* 64 reserved */
  byte nplanes;				/* 65 num of bitplanes */
  byte bytelinelo,bytelinehi;		/* 66 - 67 bytes per line */
  byte unused2[60];			/* 68 - 127 unused */
  };  /* palette info is after image data */


/* prototypes */
void dispbyte(unsigned char *ptr,int *xp,int *yp,int c,int w,int h,
              int real_bpp,int byteline,int *planep,int *pmaskp);


/* _read_pcx() is called from read_pcx(), read_gif(), read_ppm(),
   read_tif() and read_epsf().
 */

void pcx_decode();

_read_pcx(pcxfile,pic)
    FILE	*pcxfile;
    F_pic	*pic;
{
	int		 w,h,bytepp,x,y,yy,byteline,plane,pmask;
	struct pcxhed	 header;
	int		 count,waste;
	long		 bytemax,bytesdone;
	byte		 inbyte,inbyte2;
	int		 real_bpp;		/* how many bpp file really is */

	fprintf(tfp, "%% Begin Imported PCX File: %s\n\n", pic->file);
	pic->subtype = P_PCX;

	pic->bitmap=NULL;

	fread(&header,1,sizeof(struct pcxhed),pcxfile);
	if (header.manuf!=10 || header.encod!=1)
	    return 0;

	/* header.bpp=1, header.nplanes=1 = 1-bit.
	 * header.bpp=1, header.nplanes=2 = 2-bit.   - added B.V.Smith 6/00
	 * header.bpp=1, header.nplanes=3 = 3-bit.   - added B.V.Smith 6/00
	 * header.bpp=1, header.nplanes=4 = 4-bit.
	 * header.bpp=8, header.nplanes=1 = 8-bit.
	 * header.bpp=8, header.nplanes=3 = 24-bit.
	 * anything else gives an `unsupported' error.
	 */
	real_bpp=0;
	bytepp = 1;
	switch(header.bpp) {
	  case 1:
	    switch(header.nplanes) {
	      case 1: real_bpp=1; break;
	      case 2: real_bpp=2; break;
	      case 3: real_bpp=3; break;
	      case 4: real_bpp=4; break;
	    }
	    break;
	  
	  case 8:
	    switch(header.nplanes) {
	      case 1: real_bpp=8; break;
	      case 3: real_bpp=24; bytepp = 3; break;
	    }
	    break;
	  }

	if (!real_bpp)
	    return 0;

	w=(header.x2lo+256*header.x2hi)-(header.x1lo+256*header.x1hi)+1;
	h=(header.y2lo+256*header.y2hi)-(header.y1lo+256*header.y1hi)+1;
	byteline=header.bytelinelo+256*header.bytelinehi;

	if (w==0 || h==0)
	    return 0;

	x=0; y=0;
	bytemax=w*h;
	if (real_bpp==1 || real_bpp==4)
	    bytemax=(1<<30);	/* we use a 'y<h' test instead for these files */

	if ((pic->bitmap=malloc(w*(h+2)*bytepp))==NULL)
	    return 0;

	/* need this if more than one bitplane */
	memset(pic->bitmap,0,w*h*bytepp);

	bytesdone=0;

	/* start reading image */
	for (yy=0; yy<h; yy++) {
	  plane=0;
	  pmask=1;
	  
	  y=yy;
	  x=0;
	  while (y==yy) {
	    inbyte=fgetc(pcxfile);
	    if (inbyte<192) {
	      dispbyte(pic->bitmap,&x,&y,inbyte,w,h,real_bpp,
		byteline,&plane,&pmask);
	      bytesdone++;
	    } else {
	      inbyte2=fgetc(pcxfile);
	      inbyte&=63;
	      for (count=0; count<inbyte; count++)
		dispbyte(pic->bitmap,&x,&y,inbyte2,w,h,real_bpp,
			byteline,&plane,&pmask);
	      bytesdone+=inbyte;
	    }
	  }
	}

	/* read palette */
	switch(real_bpp) {
	    case 1:
		pic->cmap[RED][0] = pic->cmap[GREEN][0] = pic->cmap[BLUE][0] = 0;
		pic->cmap[RED][1] = pic->cmap[GREEN][1] = pic->cmap[BLUE][1] = 255;
		pic->numcols = 2;
		break;
	  
	    case 2:
	    case 3:
	    case 4:
		/* 2-,3-, and 4-bit, palette is embedded in header */
		pic->numcols = (1<<real_bpp);
		for (x=0; x < pic->numcols; x++) {
		    pic->cmap[RED][x] = header.pal16[x*3  ];
		    pic->cmap[GREEN][x] = header.pal16[x*3+1];
		    pic->cmap[BLUE][x] = header.pal16[x*3+2];
		    /* if user wants grayscale (-N) then map to gray */
		    if (grayonly)
			pic->cmap[RED][x] = pic->cmap[GREEN][x] = pic->cmap[BLUE][x] = 
			    (int) (rgb2luminance(pic->cmap[RED][x]/255.0, 
						pic->cmap[GREEN][x]/255.0, 
						pic->cmap[BLUE][x]/255.0)*255.0);
		}
		break;

	    case 8:
		/* 8-bit */
		waste=fgetc(pcxfile);                    /* ditch splitter byte */
		for (x=0; x<256; x++) {
		    pic->cmap[RED][x] = fgetc(pcxfile);
		    pic->cmap[GREEN][x] = fgetc(pcxfile);
		    pic->cmap[BLUE][x] = fgetc(pcxfile);
		    /* if user wants grayscale (-N) then map to gray */
		    if (grayonly)
			pic->cmap[RED][x] = pic->cmap[GREEN][x] = pic->cmap[BLUE][x] = 
			    (int) (rgb2luminance(pic->cmap[RED][x]/255.0, 
						pic->cmap[GREEN][x]/255.0, 
						pic->cmap[BLUE][x]/255.0)*255.0);
		}
		pic->numcols = 256;
		break;
	  
	    case 24:
		/* no palette, set flag in numcols to write out rgb values */
		pic->numcols = 2<<24;
		break;
	}

	pic->bit_size.x = w;
	pic->bit_size.y = h;

	return 1;  
}


void
dispbyte(unsigned char *ptr,int *xp,int *yp,int c,int w,int h,
              int real_bpp,int byteline,int *planep,int *pmaskp)
{
	int f;
	unsigned char *dstptr;

	switch(real_bpp) {
	  case 1:
	  case 2:
	  case 3:
	  case 4:
		/* mono or 4-bit */

		if ((*yp)>=h)
		    return;

		dstptr=ptr+(*yp)*w+*xp;
		w=byteline*8;

		for (f=0; f<8; f++) {
		   *dstptr++|=(c&(0x80>>(f&7)))?(*pmaskp):0;
		   (*xp)++;
		   if (*xp>=w) {
			if (real_bpp==1) {
			    (*xp)=0,(*yp)++;
			    return;
			}
			(*xp)=0;
			(*planep)++;
			(*pmaskp)<<=1;
			if (real_bpp==2) {
			    if (*planep==2) {
				(*yp)++;
				return;
			    }
			} else if (real_bpp==3) {
			    if (*planep==3) {
				(*yp)++;
				return;
			    }
			} else {
			    /* otherwise, it's 4 bpp */
			    if (*planep==4) {
				(*yp)++;
				return;
			    }
			}
		    }
		    if ((*yp)>=h)
			return;
		}
		break;
	  
	  case 8:
		*(ptr+(*yp)*w+*xp)=c;
		(*xp)++;
		if (*xp>=w) {
		    (*xp)=0;
		    (*yp)++;
		}
		break;
	  
	  case 24:
		*(ptr+((*yp)*w+*xp)*3+(2-(*planep)))=c;
		(*xp)++;
		if (*xp>=w) {
		    (*xp)=0;
		    (*planep)++; /* no need to change pmask */
		    if (*planep==3) {
			(*yp)++;
			return;
		    }
		}
		break;
	  }
}