/* 
 * libbmeps - Bitmap to EPS conversion library
 * Copyright (C) 2000 - Dirk Krause
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 * In this package the copy of the GNU Library General Public License
 * is placed in file COPYING.
 */

#include <bmepsco.h>
#include <pngeps.h>
#include <bmeps.h>
#include <bmepsoe.h>

$(trace-include)

#if HAVE_ZLIB
#if HAVE_LIBPNG

#include <png.h>


static char default_name[] = { "noname.png" };


/*
static int a2t(int x, int alpha, int trans, int aldual, int altrig)
{
  int back = 0;
  $? "+ a2t x=%d alpha=%d trans=%d dual=%d tr=%d", x, alpha, trans, aldual, altrig
  if(alpha) {
    if(!trans) {
      back = 255 - x;
    }
    if(aldual) {
      if(altrig) {
	if(back > 0) { back = 255; }
      } else {
	if(back < 255) { back = 0; }
      }
    }
  } $? "- a2t %d", back
  return back;
}
*/

static int new_bit_depth(int alt, int newbits, int altbits)
{
  int back = 0;
  unsigned long a, b, nb, ab;
  $? "+ new_bit_depth x=%d newbits=%d altbits=%d", alt, newbits, altbits
  a = alt; nb = newbits; ab = altbits;
  b = (((2UL ^ nb)-1UL)*(a)) / ((2UL ^ ab) - 1UL);
  back = b;
  $? "- new_bit_depth %d", back
  return back;
}

static int ntsc(int red, int green, int blue)
{
  int back = 0;
  unsigned long r, g, b, bck;
  $? "+ ntsc %d %d %d", red, green, blue
  r = red; g = green; b = blue;
  bck = ((54UL * r) + (183UL * g) + (19UL * b)) / 256UL;
  back = bck;
  $? "- ntsc %d", back
  return back;
}

static int mix_colors(int fg, int bg, int alpha, int tr)
{
  int back = 0;
  unsigned long f, b, a, bck;
  $? "+ mix_colors fg=%d bg=%d a=%d tr=%d", fg, bg, alpha, tr
  if(tr) { a = (255UL - alpha) ; }
  else   { a = alpha; }
  f = fg; b = bg;
  bck = ((a * f) + ((255UL - a) * b)) / 255UL;
  back = bck; $? "- mix_colors %d", back
  return back;
}

static int
png_run(FILE *out, FILE *in, char *name, unsigned long *w, unsigned long *h, int cmd)
{
  int back = 0;
  png_structp pp;
  png_infop   pi;
  unsigned long	wi;	/* width */
  unsigned long	he;	/* height */
  unsigned long  i, j, x, y;
  int		bd;	/* bit depth */
  int		ct, cu;	/* color type */
  int		it;	/* interlace type */
  int		zt;	/* compression type */
  int		ft;	/* filter type */
  int		ch; 	/* channels */
  int		alpha;
  int		trans;
  int		altrig;
  int		rowbytes;
  int		mix;	/* mix foreground and background */
  int		specbg;	/* specified background from command line */
  int		bg_red, bg_green, bg_blue;
  png_bytep	row, *rows, *rowp;
  png_color_16	bg;
  png_color_16p	bgp;

  if(in) {
    alpha = bmeps_get_alpha();
    trans = bmeps_get_trans();
    altrig = bmeps_get_altrig();
    mix = bmeps_get_mix();
    specbg = bmeps_get_specbg();
    bg_red = bmeps_get_bg_red();
    bg_green = bmeps_get_bg_green();
    bg_blue = bmeps_get_bg_blue();
    rewind(in);
    pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if(pp) { $? ". pp created"
      pi = png_create_info_struct(pp);
      if(pi) { $? ". pi created"
	png_init_io(pp, in); $? ". image initialized"
	png_read_info(pp, pi); $? ". info was read"
	png_get_IHDR(pp, pi, &wi, &he, &bd, &ct, &it, &zt, &ft);
	$? ". width =           %lu", wi
	$? ". height =          %lu", he
	$? ". bitdepth =        %d", bd
	$? ". colortype =       %d", ct
	$? ". interlace =       %d", it
	$? ". compressiontype = %d", zt
	$? ". filtertype =      %d", ft
	cu = ct;
	ch = png_get_channels(pp, pi);
	$? ". channels =        %d", ch
	switch(cmd) {
	  case 0: {
	    if(out) {
	      bmeps_header(
		out, (name ? name : default_name),
		wi, he
	      );
	      if(bmeps_get_draft()) {
		back = 1;
		bmeps_draft(out, wi, he);
	      } else {
		int need_expansion;
		int need_strip;
		int need_pack;
		need_expansion = 0;
		need_strip = 0;
		need_pack  = 0;
		if((ct == PNG_COLOR_TYPE_PALETTE) && (bd <= 8)) {
		  need_expansion = 1;
		}
		if((ct == PNG_COLOR_TYPE_GRAY) && (bd < 8)) {
		  need_expansion = 1;
		}
		if(png_get_valid(pp, pi, PNG_INFO_tRNS)) {
		  need_expansion = 1;
		}
		if(bd > 8) {
		  need_strip = 1;
		} else {
		  if(bd < 8) {
		    need_pack = 1;
		  }
		}
		if(need_expansion) {
		  png_set_expand(pp);
		}
		if(need_strip) {
		  png_set_strip_16(pp);
		}
		if(need_pack) {
		  png_set_packing(pp);
		}
		bgp = &bg;
		bg.red = bg_red;
		bg.green = bg_green;
		bg.blue = bg_blue;
		bg.gray = ntsc(bg.red, bg.green, bg.blue);
		bg.index = 0;
		$? ". have alpha support"
		if(!(alpha)) {
		  $? ". alpha support not in use"
		  if(png_get_bKGD(pp, pi, &bgp)) {
		    png_set_background(pp,bgp,PNG_BACKGROUND_GAMMA_FILE,1,1.0);
		  } else {
		    png_set_background(pp,&bg,PNG_BACKGROUND_GAMMA_SCREEN,0,1.0);
		  }
		} else { $? ". alpha support in use"
		  if(png_get_bKGD(pp, pi, &bgp) && (!specbg)) {
		    $? ". background chunk contained"
		    if(ct & PNG_COLOR_MASK_PALETTE) {
		      png_colorp ptr; int num; $? ". paletted PNG"
		      if(png_get_PLTE(pp, pi, &ptr, &num)) {
			$? ". palette was read"
		        if(bgp->index < num) { $? ". backround index in range"
			  if(bd != 8) { $? ". bitdepth needs correction"
			    bg.red = new_bit_depth(ptr[bgp->index].red, 8, bd);
			    bg.green = new_bit_depth(
			      ptr[bgp->index].green, 8, bd
			    );
			    bg.blue = new_bit_depth(
			      ptr[bgp->index].blue, 8, bd
			    );
			    bg.gray = ntsc(
			      bg.red, bg.green, bg.blue
			    );
			  } else { $? ". bitdepth ok"
			    bg.red = ptr[bgp->index].red;
			    bg.green = ptr[bgp->index].green;
			    bg.blue = ptr[bgp->index].blue;
			    bg.gray = ntsc(bg.red, bg.green, bg.blue);
			  }
		        } else { $? "! background index out of range"
		          bg.red = bg_red;
		          bg.green = bg_green;
		          bg.blue = bg_blue;
		          bg.gray = ntsc(bg.red, bg.green, bg.blue);
			  bg.index = 0;
		        }
		      } else { $? "! failed to read palette"
		        bg.red = bg_red;
		        bg.green = bg_green;
		        bg.blue = bg_blue;
		        bg.gray = ntsc(bg.red, bg.green, bg.blue);
		        bg.index = 0;
		      }
		    } else { $? ". not paletted"
		      if(bd != 8) { $? ". bitdepth ok"
		        bg.red = new_bit_depth( bgp->red, 8, bd);
		        bg.blue = new_bit_depth( bgp->blue, 8, bd);
		        bg.green = new_bit_depth( bgp->green, 8, bd);
		        bg.gray = new_bit_depth( bgp->gray, 8, bd);
		      } else { $? ". need to correct bitdepth"
		        bg.red = bgp->red;
		        bg.blue = bgp->blue;
		        bg.green = bgp->green;
		        bg.gray = bgp->gray;
		      }
		      bg.index = 0;
		    }
		  } else { $? ". no background chunk contained or chunk unused"
		    bg.red = bg_red;
		    bg.green = bg_green;
		    bg.blue = bg_blue;
		    bg.gray = ntsc(bg.red, bg.green, bg.blue);
		    bg.index = 0;
		  }
		}
		/* place gamma correction here */
		/* place interlace handling here */
		png_read_update_info(pp, pi);
		ch = png_get_channels(pp, pi);
		ct = png_get_color_type(pp, pi);
		$? ". colortype now %d", ct
		$? ". channels now %d", ch
		rowbytes = png_get_rowbytes(pp, pi);
		rows = (png_bytep *)malloc(he*sizeof(png_bytep));
		if(rows) {
		  back = 1; rowp = rows;
		  for(y = 0; y < he; y++) {
		    *rowp = NULL;
		    row = (png_bytep)malloc(rowbytes*sizeof(png_byte));
		    if(row) {
		      *rowp = row;
		    } else {
		      back = 0;
		    }
		    rowp++;
		  }
		  if(back) {
		    png_read_image(pp, rows);
		    if((ct & PNG_COLOR_MASK_ALPHA) && alpha) {
		      $? ". alpha channel detected"
		      bmeps_set_trans(1);
		    } else { $? ". no alpha channel in picture"
		    }
		    bmeps_begin_image(
		      out, wi, he
		    );
		    rowp = rows;
		    for(y = 0; y < he; y++) {
		      row = *(rowp++);
		      for(x = 0; x < wi; x++) {
			if((ct & PNG_COLOR_MASK_ALPHA) && alpha) {
			  $? ". alpha %lu %lu", x, y
			  bmeps_add_trans(
			    255-row[(x+1UL)*((unsigned long)ch)-1UL]
			  );
			}
			if(ct & PNG_COLOR_MASK_COLOR) {
			  $? ". rgb %lu %lu", x, y
			  if((ct & PNG_COLOR_MASK_ALPHA) && alpha && mix) {
			    /* 4 lines for debugging only */
			    static int firstrun = 1;
			    if(firstrun) { $? ". MIXING COLORS WITH BACKGROUND"
			    }
			    firstrun = 0;
			    bmeps_add_rgb(
			      mix_colors(
				row[x*((unsigned long)ch)],
				bg.red,
				row[(x+1UL)*((unsigned long)ch)-1UL],
				trans
			      ),
			      mix_colors(
				row[x*((unsigned long)ch)+1UL],
				bg.green,
				row[(x+1UL)*((unsigned long)ch)-1UL],
				trans

			      ),
			      mix_colors(
				row[x*((unsigned long)ch)+2UL],
				bg.blue,
				row[(x+1UL)*((unsigned long)ch)-1UL],
				trans
			      )
			    );
			  } else {
			    /* 4 lines for debugging only */
			    static int firstrun = 1;
			    if(firstrun) { $? ". NOT MIXING COLORS WITH BACKGROUND"
			    }
			    firstrun = 0;
			    bmeps_add_rgb(
			      row[x*((unsigned long)ch)],
			      row[x*((unsigned long)ch)+1UL],
			      row[x*((unsigned long)ch)+2UL]
			    );
			  }
			} else {
			  if((ct & PNG_COLOR_MASK_ALPHA) && alpha && mix) {
			    /* 4 lines for debugging only */
			    static int firstrun = 1;
			    if(firstrun) { $? ". MIXING GRAY WITH BACKGROUND"
			    }
			    firstrun = 0;
			    bmeps_add_gray(
			      mix_colors(
				row[x*((unsigned long)ch)],
				bg.gray,
				row[(x+1UL)*((unsigned long)ch)-1UL],
				trans
			      )
			    );
			  } else {
			    /* 4 lines for debugging only */
			    static int firstrun = 1;
			    if(firstrun) { $? ". MIXING GRAY WITH BACKGROUND"
			    }
			    firstrun = 0;
			    $? ". gray %lu %lu", x, y
			    bmeps_add_gray(
			      row[x*((unsigned long)ch)]
			    );
			  }
			}
		      }
		    }
		    bmeps_end_image(out);
		    $? ". image finished"
		  }
		  /* done with rows */
		  rowp = rows;
		  for(y = 0; y < he; y++) {
		    row = *rowp;
		    if(row) { free(row); }
		    *(rowp++) = NULL;
		  }
		  free(rows);
		} else { $? "! memory allocation failed for rows"
		}
	      }
	      bmeps_footer(out);
	    }
	  } break;
	  case 1: {
	    if(out) {
	      back = 1;
	      bmeps_bb(out, wi, he);
	    }
	  } break;
	  case 2: {
	    if(w && h) {
	      back = 1;
	      *w = wi;
	      *h = he;
	    }
	  } break;
	}
	/* done with it */
	png_destroy_info_struct(pp, &pi);
      } else { $? "! failed to create pi"
      }
      png_destroy_read_struct(&pp, NULL, NULL);
    } else { $? "! failed to create pp"
    }
  }
  return back;
}

#else
/* HAVE_LIBPNG */

static int
png_run(FILE *out, FILE *in, char *name, unsigned long *w, unsigned long *h, int cmd)
{
  return 0;
}

#endif
/* HAVE_LIBPNG */

#else
/* HAVE_ZLIB */

static int
png_run(FILE *out, FILE *in, char *name, unsigned long *w, unsigned long *h, int cmd)
{
  return 0;
}

#endif
/* HAVE_ZLIB */

int bmeps_png(FILE *out, FILE *in, char *name)
{
  int back;
  if(out && in) {
  bmeps_configure();
  back = png_run(out, in, name, NULL, NULL, 0);
  }
  return back;
}

int bmeps_png_bb(FILE *out, FILE *in, char *name)
{
  int back;
  if(out && in) {
  bmeps_configure();
  back = png_run(out, in, name, NULL, NULL, 1);
  }
  return back;
}

int bmeps_png_wh(FILE *in, unsigned long *w, unsigned long *h)
{
  int back = 0;
  if(w && h && in) {
    bmeps_configure();
    back = png_run(NULL, in, NULL, w, h, 2);
  }
  return back;
}


#ifndef LINT
static char sccs_id[] = {
  "@(#)09/26/00\t1.12\tpngeps.ctr\t(krause) PNG to EPS conversion module"
};
#endif