Changes in gif2png 0.7 (5 September 1999)
-----------------------------------------

 - modified to swap transparent palette entry with 0th entry to avoid large
    tRNS chunks (since many programs make *last* entry the transparent one)
 - modified for auto-interlace:  make interlaced PNG only if GIF is interlaced
 - added -n option to disable interlacing (-i still forces interlacing)
 - added -q option for mostly quiet operation (-qq for totally quiet, aside
    from error messages)
 - inverted -p option so progress percentage only displayed if requested
 - added summary line ("converted N GIFs to M PNGs")
 - improved version info and usage screen
 - quieted some gcc warnings

Note that the transparency-swapping fix has not been tested in conjunction
with a background-color GIF; I don't have any (that I know of).  In general
it shouldn't be a problem.

Greg Roelofs
12 September 1999


diff -c gif2png-0.6/Makefile gif2png-0.7/Makefile
*** gif2png-0.6/Makefile	Fri Nov  3 15:48:22 1995
--- gif2png-0.7/Makefile	Sun Sep  5 12:30:00 1999
***************
*** 5,21 ****
  #COFF2EXE=coff2exe
  COFF2EXE=@echo >/dev/null
  
! PNGLIB=libpng-0.81
! ZLIB=zlib-0.95
  
  LIBS=$(PNGLIB)/libpng.a $(ZLIB)/libz.a
- INCLUDE=-I$(PNGLIB) -I$(ZLIB)
  
! CFLAGS=$(INCLUDE) -g -O -Wall
! LDFLAGS=-g
  
! #CFLAGS=$(INCLUDE) -O -Wall
! #LDFLAGS=-s
  
  OBJS=gif2png.o gifread.o version.o 437_l1.o memory.o
  
--- 5,28 ----
  #COFF2EXE=coff2exe
  COFF2EXE=@echo >/dev/null
  
! #PNGINC=libpng-0.81
! #PNGLIB=libpng-0.81
! PNGINC=/usr/include
! PNGLIB=/usr/lib
! 
! #ZINC=zlib-0.95
! #ZLIB=zlib-0.95
! ZINC=/usr/include
! ZLIB=/usr/lib
  
+ INCLUDE=-I$(PNGINC) -I$(ZINC)
  LIBS=$(PNGLIB)/libpng.a $(ZLIB)/libz.a
  
! #CFLAGS=$(INCLUDE) -g -O -Wall
! #LDFLAGS=-g
  
! CFLAGS=$(INCLUDE) -O3 -Wall
! LDFLAGS=-s
  
  OBJS=gif2png.o gifread.o version.o 437_l1.o memory.o
  
***************
*** 31,37 ****
  gifread.o: gifread.c gif2png.h
  memory.o: memory.c gif2png.h
  
! version.o: version.c
  	$(CC) $(CFLAGS) -c version.c -DPNGLIB=\"$(PNGLIB)\" -DZLIB=\"$(ZLIB)\"
  
  tags:  .force
--- 38,44 ----
  gifread.o: gifread.c gif2png.h
  memory.o: memory.c gif2png.h
  
! version.o: version.c gif2png.c gifread.c memory.c 437_l1.c gif2png.h
  	$(CC) $(CFLAGS) -c version.c -DPNGLIB=\"$(PNGLIB)\" -DZLIB=\"$(ZLIB)\"
  
  tags:  .force
diff -c gif2png-0.6/gif2png.c gif2png-0.7/gif2png.c
*** gif2png-0.6/gif2png.c	Fri Nov  3 17:52:44 1995
--- gif2png-0.7/gif2png.c	Sun Sep  5 12:41:37 1999
***************
*** 1,24 ****
  /*
   * gif2png.c
   * Copyright (C) 1995 Alexander Lehmann
   * For conditions of distribution and use, see copyright notice in gif2png.h
   */
  
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #define PNG_INTERNAL
  #include "gif2png.h"
  
  struct GIFelement first={NULL};
  struct GIFelement *current;
! int delete;
! int histogram;
! int interlaced;
! int progress;
! int recover;
! int software_chunk;
! int skip_pte;
  
  /* return the actual line # used to store an interlaced line */
  
--- 1,30 ----
  /*
   * gif2png.c
   * Copyright (C) 1995 Alexander Lehmann
+  * (Bug fixes and enhancements by Greg Roelofs, 5 September 1999)
   * For conditions of distribution and use, see copyright notice in gif2png.h
   */
  
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
+ #include <unistd.h>	/* for isatty() */
+ 
  #define PNG_INTERNAL
  #include "gif2png.h"
  
  struct GIFelement first={NULL};
  struct GIFelement *current;
! int delete = 0;
! int histogram = 0;
! int interlaced = -1;
! int progress = 0;
! int quiet = 0;
! int recover = 0;
! int software_chunk = 1;
! int skip_pte = 1;
! long numgifs = 0L;
! long numpngs = 0L;
  
  /* return the actual line # used to store an interlaced line */
  
***************
*** 67,77 ****
     except when the transparency color is also appearing as a visible color. In
     this case we write a paletted image, another solution would be gray+alpha,
     but that would probably increase the image size too much.
!    If there are only few gray levels (<=16), we try to create a 4 or less bit
     grayscale file, but if the gray levels do not fit into the necessary grid,
!    we write a paletted image, e.g. if the image contains black, white and 50%
!    gray, the grayscale image would require 8 bit, but the paletted image only
!    2 bit. Even with filtering, the 8 bit file will be larger.
  */
  
  int graycheck(png_color c)
--- 73,83 ----
     except when the transparency color is also appearing as a visible color. In
     this case we write a paletted image, another solution would be gray+alpha,
     but that would probably increase the image size too much.
!    If there are only few gray levels (<=16), we try to create a 4-bit or less
     grayscale file, but if the gray levels do not fit into the necessary grid,
!    we write a paletted image--e.g., if the image contains black, white and 50%
!    gray, the grayscale image would require 8-bit, but the paletted image only
!    2-bit. Even with filtering, the 8-bit file will be larger.
  */
  
  int graycheck(png_color c)
***************
*** 88,101 ****
    struct GIFimagestruct *img=e->imagestruct;
    unsigned long *count=img->color_count;
    GifColor *colors=img->colors;
!   int gray;
!   int last_color=0, colors_used=0;
    byte remap[MAXCMSIZE];
!   int low_presc;
    png_struct *png_ptr = xalloc(sizeof (png_struct));
    png_info *info_ptr = xalloc(sizeof (png_info));
    int p;
!   int bitdepth, gray_bitdepth;
    png_byte pal_trans[MAXCMSIZE];
    png_color_16 color16trans, color16back;
    byte buffer[24]; /* used for gIFt and gIFg */
--- 94,107 ----
    struct GIFimagestruct *img=e->imagestruct;
    unsigned long *count=img->color_count;
    GifColor *colors=img->colors;
!   int colors_used=0;
    byte remap[MAXCMSIZE];
!   int low_prec;
    png_struct *png_ptr = xalloc(sizeof (png_struct));
    png_info *info_ptr = xalloc(sizeof (png_info));
    int p;
!   int gray_bitdepth;
!   png_color pal_rgb[MAXCMSIZE];
    png_byte pal_trans[MAXCMSIZE];
    png_color_16 color16trans, color16back;
    byte buffer[24]; /* used for gIFt and gIFg */
***************
*** 106,111 ****
--- 112,124 ----
    int passcount;
    png_text software;
  
+   /* these static declarations prevent gcc warnings ("variable might be
+    *  clobbered by `longjmp' or `vfork'") */
+   static int gray;
+   static int last_color=0;
+   static int remapping=0;
+   static int bitdepth;
+ 
    if(img->trans!=-1 && !count[img->trans])
      img->trans=-1;
  
***************
*** 119,125 ****
      }
  
    if(gray) {
!     fprintf(stderr, "image is grayscale\n");
  
      /* zero out unused colors */
  
--- 132,139 ----
      }
  
    if(gray) {
!     if (!quiet)
!       fprintf(stderr, "image is grayscale\n");
  
      /* zero out unused colors */
  
***************
*** 132,138 ****
        for(i=0;i<MAXCMSIZE;i++) {
          if(i!=img->trans && colors[i].red==colors[img->trans].red) {
            gray=0;
!           fprintf(stderr, "trans color is repeated in visible colors, using palette\n");
            break;
          }
        }
--- 146,154 ----
        for(i=0;i<MAXCMSIZE;i++) {
          if(i!=img->trans && colors[i].red==colors[img->trans].red) {
            gray=0;
!           if (!quiet)
!             fprintf(stderr,
!               "trans color is repeated in visible colors, using palette\n");
            break;
          }
        }
***************
*** 145,150 ****
--- 161,167 ----
    if(last_color<2) bitdepth=1;
  
    if(gray) {
+     remapping = 1;
      for(i=0;i<MAXCMSIZE;i++)
        remap[i]=colors[i].red;
    }
***************
*** 152,202 ****
    if(gray) {
      gray_bitdepth=8;
  
!     /* try to adjust to 4 bit prescision grayscale */
  
!     low_presc=1;
      for(i=0;i<MAXCMSIZE;i++) {
!       if((remap[i]&0xf)*0x11!=remap[i]) {
!         low_presc=0;
          break;
        }
      }
!     if(low_presc) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 0xf;
        }
        gray_bitdepth=4;
      }
  
!     /* try to adjust to 2 bit prescision grayscale */
  
!     if(low_presc) {
        for(i=0;i<MAXCMSIZE;i++) {
!         if((remap[i]&3)*5!=remap[i]) {
!           low_presc=0;
            break;
          }
        }
      }
  
!     if(low_presc) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 3;
        }
        gray_bitdepth=2;
      }
  
!     /* try to adjust to 1 bit prescision grayscale */
  
!     if(low_presc) {
        for(i=0;i<MAXCMSIZE;i++) {
!         if((remap[i]&1)*3!=remap[i]) {
!           low_presc=0;
            break;
          }
        }
      }
!     if(low_presc) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 1;
        }
--- 169,219 ----
    if(gray) {
      gray_bitdepth=8;
  
!     /* try to adjust to 4-bit precision grayscale */
  
!     low_prec=1;
      for(i=0;i<MAXCMSIZE;i++) {
!       if((remap[i]&0xf)*0x11 != remap[i]) {
!         low_prec=0;
          break;
        }
      }
!     if(low_prec) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 0xf;
        }
        gray_bitdepth=4;
      }
  
!     /* try to adjust to 2-bit precision grayscale */
  
!     if(low_prec) {
        for(i=0;i<MAXCMSIZE;i++) {
!         if((remap[i]&3)*5 != remap[i]) {
!           low_prec=0;
            break;
          }
        }
      }
  
!     if(low_prec) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 3;
        }
        gray_bitdepth=2;
      }
  
!     /* try to adjust to 1-bit precision grayscale */
  
!     if(low_prec) {
        for(i=0;i<MAXCMSIZE;i++) {
!         if((remap[i]&1)*3 != remap[i]) {
!           low_prec=0;
            break;
          }
        }
      }
!     if(low_prec) {
        for(i=0;i<MAXCMSIZE;i++) {
          remap[i] &= 1;
        }
***************
*** 210,223 ****
      }
    }
  
!   fprintf(stderr, "%d colors used, highest color %d, %s, bitdepth %d\n", colors_used, last_color, gray ? "gray":"palette", bitdepth);
  
    if(setjmp(png_ptr->jmpbuf)) {
!     fprintf(stderr, "setjmp returns error condition\n");
! 
      free(png_ptr);
      free(info_ptr);
- 
      return 1;
    }
  
--- 227,240 ----
      }
    }
  
!   if (!quiet)
!     fprintf(stderr, "%d colors used, highest color %d, %s, bitdepth %d\n",
!       colors_used, last_color, gray ? "gray":"palette", bitdepth);
  
    if(setjmp(png_ptr->jmpbuf)) {
!     fprintf(stderr, "gif2png:  libpng returns fatal error condition\n");
      free(png_ptr);
      free(info_ptr);
      return 1;
    }
  
***************
*** 228,234 ****
    info_ptr->height=current->imagestruct->height;
    info_ptr->bit_depth=bitdepth;
    info_ptr->color_type=gray ? PNG_COLOR_TYPE_GRAY : PNG_COLOR_TYPE_PALETTE;
!   info_ptr->interlace_type=interlaced;
  
    if(GifScreen.AspectRatio!=0 && GifScreen.AspectRatio!=49) {
      info_ptr->x_pixels_per_unit=GifScreen.AspectRatio+15;
--- 245,254 ----
    info_ptr->height=current->imagestruct->height;
    info_ptr->bit_depth=bitdepth;
    info_ptr->color_type=gray ? PNG_COLOR_TYPE_GRAY : PNG_COLOR_TYPE_PALETTE;
!   if (interlaced == -1)
!     info_ptr->interlace_type = current->imagestruct->interlace;
!   else
!     info_ptr->interlace_type = interlaced;
  
    if(GifScreen.AspectRatio!=0 && GifScreen.AspectRatio!=49) {
      info_ptr->x_pixels_per_unit=GifScreen.AspectRatio+15;
***************
*** 251,258 ****
  
      if(gray) {
        if(graycheck(GifScreen.ColorMap[GifScreen.Background])) {
!         color16back.gray=remap[GifScreen.Background];
!         info_ptr->background=color16back;
          info_ptr->valid |= PNG_INFO_bKGD;
        }
      } else {
--- 271,278 ----
  
      if(gray) {
        if(graycheck(GifScreen.ColorMap[GifScreen.Background])) {
!         color16back.gray = remap[GifScreen.Background];
!         info_ptr->background = color16back;
          info_ptr->valid |= PNG_INFO_bKGD;
        }
      } else {
***************
*** 272,291 ****
  
    if(img->trans != -1) {
      if(gray) {
!       color16trans.gray=remap[img->trans];
!       info_ptr->trans_values=color16trans;
      } else {
!       for(i=0;i<MAXCMSIZE;i++) pal_trans[i]=255;
        pal_trans[img->trans]=0;
        info_ptr->trans=pal_trans;
        info_ptr->num_trans=img->trans+1;
      }
      info_ptr->valid |= PNG_INFO_tRNS;
    }
  
    if(!gray) {
!     info_ptr->palette=current->imagestruct->colors;
!     info_ptr->num_palette=last_color+1;
      info_ptr->valid |= PNG_INFO_PLTE;
    }
  
--- 292,333 ----
  
    if(img->trans != -1) {
      if(gray) {
!       color16trans.gray = remap[img->trans];
!       info_ptr->trans_values = color16trans;
      } else {
! #if 0
!       for(i=0;i<MAXCMSIZE;i++)
!         pal_trans[i]=255;
        pal_trans[img->trans]=0;
        info_ptr->trans=pal_trans;
        info_ptr->num_trans=img->trans+1;
+ #else
+       /* GRR NOTE:  may be inconsistent with background-color logic (above) */
+       remapping = 1;
+       for(i=0;i<MAXCMSIZE;i++)
+         remap[i] = i;
+       remap[0] = img->trans;
+       remap[img->trans] = 0;
+       pal_trans[0] = 0;
+       info_ptr->trans = pal_trans;
+       info_ptr->num_trans = 1;
+ #endif
      }
      info_ptr->valid |= PNG_INFO_tRNS;
    }
  
    if(!gray) {
!     if (remapping) {
!       for(i=0; i<=last_color; i++) {
!         pal_rgb[i].red   = current->imagestruct->colors[remap[i]].red;
!         pal_rgb[i].green = current->imagestruct->colors[remap[i]].green;
!         pal_rgb[i].blue  = current->imagestruct->colors[remap[i]].blue;
!       }
!       info_ptr->palette = pal_rgb;
!     } else {
!       info_ptr->palette = current->imagestruct->colors;
!     }
!     info_ptr->num_palette = last_color+1;
      info_ptr->valid |= PNG_INFO_PLTE;
    }
  
***************
*** 350,358 ****
            for(i=0;i<current->imagestruct->height;i++) {
              if(progress) {
                if(passcount>1)
!                 printf("%d/%d ", p+1, passcount);
!               printf("%2d%%\r", (int)(((long)i*100)/current->imagestruct->height));
!               fflush(stdout);
              }
              data=access_data(current, (long) (img->interlace ?
                               interlace_line(current->imagestruct->height,i) : i) *
--- 392,401 ----
            for(i=0;i<current->imagestruct->height;i++) {
              if(progress) {
                if(passcount>1)
!                 fprintf(stderr, "%d/%d ", p+1, passcount);
!               fprintf(stderr, "%2d%%\r",
!                 (int)(((long)i*100)/current->imagestruct->height));
!               fflush(stderr);
              }
              data=access_data(current, (long) (img->interlace ?
                               interlace_line(current->imagestruct->height,i) : i) *
***************
*** 360,370 ****
                               current->imagestruct->width);
  #ifndef TMPFILE
              /* if we store the image in memory, we have to remap once */
!             if(gray && p==0) {
  #else
              /* if we store the image in a file, we have to remap each time */
!             if(gray) {
  #endif
                for(j=0;j<img->width;j++) {
                  data[j]=remap[data[j]];
                }
--- 403,414 ----
                               current->imagestruct->width);
  #ifndef TMPFILE
              /* if we store the image in memory, we have to remap once */
!             if(remapping && p==0)
  #else
              /* if we store the image in a file, we have to remap each time */
!             if(remapping)
  #endif
+             {
                for(j=0;j<img->width;j++) {
                  data[j]=remap[data[j]];
                }
***************
*** 397,403 ****
  #if 0
        case GIFplaintext:
          data=access_data(s, 0, s->size);
!         /* gIFt is 12 bytes longer than GCE, due to 32 bit ints and
             rgb colors */
          png_write_chunk_start(png_ptr, "gIFt", s->size+12);
          memset(buffer, 0, 24);
--- 441,447 ----
  #if 0
        case GIFplaintext:
          data=access_data(s, 0, s->size);
!         /* gIFt is 12 bytes longer than GCE, due to 32-bit ints and
             rgb colors */
          png_write_chunk_start(png_ptr, "gIFt", s->size+12);
          memset(buffer, 0, 24);
***************
*** 468,475 ****
  
    fclose(fp);
  
!   if(num_pics>=0)
!     printf("number of images %d\n", num_pics);
  
    if(num_pics<=0) return 1;
  
--- 512,519 ----
  
    fclose(fp);
  
!   if(num_pics>=0 && !quiet)
!     fprintf(stderr, "number of images %d\n", num_pics);
  
    if(num_pics<=0) return 1;
  
***************
*** 508,513 ****
--- 552,558 ----
        } else {
          writefile(start, current, fp, i==num_pics);
          fclose(fp);
+         ++numpngs;
          start=NULL;
          sprintf(file_ext, ".p%02d", i);
        }
***************
*** 544,550 ****
    char name[1025];
    int ac;
  
!   fprintf(stderr, "%s %s\n", version, compile_info);
  
  #ifdef TMPFILE
    if((tempfile=tmpfile())==NULL) {
--- 589,596 ----
    char name[1025];
    int ac;
  
!   if (quiet < 2)
!     fprintf(stderr, "%s %s\n", version, compile_info);
  
  #ifdef TMPFILE
    if((tempfile=tmpfile())==NULL) {
***************
*** 554,560 ****
  #endif
  
    software_chunk=1;
-   progress=1;
  
    ac=1;
  
--- 600,605 ----
***************
*** 573,580 ****
            interlaced=1;
            break;
  
          case 'p':
!           progress=0;
            break;
  
          case 'r':
--- 618,633 ----
            interlaced=1;
            break;
  
+         case 'n':
+           interlaced=0;
+           break;
+ 
          case 'p':
!           progress=1;
!           break;
! 
!         case 'q':
!           ++quiet;
            break;
  
          case 'r':
***************
*** 586,616 ****
            break;
  
          case 't':
!           skip_pte=1;
            break;
  
          default:
!           fprintf(stderr, "unknown option char `%c'\n", argv[ac][i]);
  usage:
            fprintf(stderr,
- "usage: gif2png [ -dhi ] [file[.gif]] ...\n"
  "\n"
! "       -d delete source GIF files after successful conversion\n"
! "       -i create interlaced PNG files\n"
! "       -h create histogram chunks for color files\n"
! "       -p do not display progress of PNG writing in %%\n"
! "       -r try to recover corrupt GIF files\n"
! "       -s do not write Software chunk\n"
! "       -t ignore Plain Text Extensions\n"
  "\n"
! "       if no source files are listed, stdin is converted to noname.png\n"
! "       (may not work on systems that distinguish between text and binary mode)\n"
  "\n"
! "       gif2png is Copyright 1995 by Alexander Lehmann <alex@hal.rhein-main.de>\n"
! "       For copyright, license, credits, etc. see the file README, which you\n"
! "       should have received along with this program. If you didn't, you may be\n"
! "       able to find gif2png on ftp://ftp.uu.net/graphics/png or on my\n"
! "       WWW-page http://www.student.informatik.th-darmstadt.de/~alexlehm/\n"
            );
            return 1;
        }
--- 639,673 ----
            break;
  
          case 't':
!           skip_pte=0;
            break;
  
          default:
!           fprintf(stderr, "unknown option `-%c'\n", argv[ac][i]);
  usage:
            fprintf(stderr,
  "\n"
! "usage: gif2png [ -dhinqprs ] [file[.gif]] ...\n"
  "\n"
! "   -d  delete source GIF files after successful conversion\n"
! "   -h  create histogram chunks for color files\n"
! "   -i  force interlaced PNG files (default = same as GIF image)\n"
! "   -n  force noninterlaced PNG files\n"
! "   -p  display progress of PNG writing in %%\n"
! "   -q  quiet mode (-qq very quiet)\n"
! "   -r  try to recover corrupted GIF files\n"
! "   -s  do not write Software text chunk\n"
! /* "   -t  convert Plain Text Extensions [not implemented]\n" */
  "\n"
! "   if no source files are listed, stdin is converted to noname.png\n"
! "   (may not work on systems that distinguish between text and binary mode)\n"
! "\n"
! "   gif2png is Copyright 1995 by Alexander Lehmann <alex@hal.rhein-main.de>\n"
! "   For copyright, license, credits, etc. see the file README, which you\n"
! "   should have received along with this program. If you didn't, you may be\n"
! "   able to find gif2png at http://www.cdrom.com/pub/png/pngcode.html ,\n"
! "   ftp://ftp.uu.net/graphics/png/applications/ , or on my WWW page\n"
! "   http://www.student.informatik.th-darmstadt.de/~alexlehm/ .\n"
            );
            return 1;
        }
***************
*** 620,626 ****
      if(input_is_terminal()) {
        goto usage;
      }
!     printf("stdin:\n");
      processfile("noname.gif", stdin);
    } else {
      for(i=ac;i<argc;i++) {
--- 677,684 ----
      if(input_is_terminal()) {
        goto usage;
      }
!     if (!quiet)
!       fprintf(stderr, "stdin:\n");
      processfile("noname.gif", stdin);
    } else {
      for(i=ac;i<argc;i++) {
***************
*** 634,645 ****
          perror(argv[i]);
          errors=1;
        } else {
!         printf("%s:\n", name);
          errors |= processfile(name, fp);
          /* fp is closed in processfile */
        }
      }
    }
  
    return errors;
  }
--- 692,710 ----
          perror(argv[i]);
          errors=1;
        } else {
!         if (!quiet)
!           fprintf(stderr, "%s:\n", name);
          errors |= processfile(name, fp);
          /* fp is closed in processfile */
+         ++numgifs;
        }
      }
    }
+ 
+   if (quiet < 2)
+     fprintf(stderr, "Done (%s).  Converted %ld GIF%s into %ld PNG%s.\n",
+       errors? "with one or more errors" : "no errors detected", 
+       numgifs, (numgifs == 1)? "" : "s", numpngs, (numpngs == 1)? "" : "s");
  
    return errors;
  }
diff -c gif2png-0.6/gifread.c gif2png-0.7/gifread.c
*** gif2png-0.6/gifread.c	Fri Nov  3 17:53:34 1995
--- gif2png-0.7/gifread.c	Sun Sep  5 12:17:52 1999
***************
*** 51,56 ****
--- 51,57 ----
  } Gif89;
  
  extern int c_437_l1[];
+ extern int quiet;
  
  static int ReadColorMap(FILE *fd, int number, GifColor buffer[MAXCMSIZE]);
  static int DoExtension(FILE *fd, int label);
***************
*** 177,189 ****
      }
  
      if (c == GIFterminator) {           /* GIF terminator */
!       fprintf(stderr, "end of GIF data stream\n");
        return(imagecount);
      }
  
      if (c == GIFextension) {    /* Extension */
        if (! ReadOK(fd,&c,1)) {
!         fprintf(stderr, "EOF / read error on extention function code\n");
          return check_recover(FALSE);
        }
        if(DoExtension(fd, c))
--- 178,191 ----
      }
  
      if (c == GIFterminator) {           /* GIF terminator */
!       if (!quiet)
!         fprintf(stderr, "end of GIF data stream\n");
        return(imagecount);
      }
  
      if (c == GIFextension) {    /* Extension */
        if (! ReadOK(fd,&c,1)) {
!         fprintf(stderr, "EOF / read error on extension function code\n");
          return check_recover(FALSE);
        }
        if(DoExtension(fd, c))
***************
*** 223,229 ****
        }
      } else {
        if(!GifScreen.ColorMap_present) {
!         fprintf(stderr, "neither global nor local colormap, using default\n");
        }
  
        if(!ReadImage(fd, x_off, y_off, w, h, GifScreen.BitPixel,
--- 225,232 ----
        }
      } else {
        if(!GifScreen.ColorMap_present) {
!         if (!quiet)
!           fprintf(stderr, "neither global nor local colormap, using default\n");
        }
  
        if(!ReadImage(fd, x_off, y_off, w, h, GifScreen.BitPixel,
***************
*** 288,294 ****
      Gif89.inputFlag = -1;
      Gif89.disposal = 0;
      if(skip_pte) {
!       fprintf(stderr, "got a 'Plain Text Extension' extension (skipping)\n");
  
        while (GetDataBlock(fd, (unsigned char*) buf) > 0)
          ;
--- 291,298 ----
      Gif89.inputFlag = -1;
      Gif89.disposal = 0;
      if(skip_pte) {
!       if (!quiet)
!         fprintf(stderr, "got a 'Plain Text Extension' extension (skipping)\n");
  
        while (GetDataBlock(fd, (unsigned char*) buf) > 0)
          ;
***************
*** 348,354 ****
        store_block(buf, size);
      }
  
!     fprintf(stderr, "got a 'Comment Extension' extension\n");
  
      current->GIFtype=label;
  
--- 352,359 ----
        store_block(buf, size);
      }
  
!     if (!quiet)
!       fprintf(stderr, "got a 'Comment Extension' extension\n");
  
      current->GIFtype=label;
  
***************
*** 380,386 ****
        goto copy_block;
      }
    default:
!     fprintf(stderr, "skipping unknown extension 0x%02x\n",
              (unsigned char)label);
      while (GetDataBlock(fd, (unsigned char*) buf) > 0)
        ;
--- 385,392 ----
        goto copy_block;
      }
    default:
!     if (!quiet)
!       fprintf(stderr, "skipping unknown extension 0x%02x\n",
              (unsigned char)label);
      while (GetDataBlock(fd, (unsigned char*) buf) > 0)
        ;
***************
*** 394,400 ****
      store_block(buf, size);
    }
  
!   fprintf(stderr, "got a '%s' extension\n", str);
  
    current->GIFtype=label;
  
--- 400,407 ----
      store_block(buf, size);
    }
  
!   if (!quiet)
!     fprintf(stderr, "got a '%s' extension\n", str);
  
    current->GIFtype=label;
  
***************
*** 561,567 ****
          ;
  
        if (count != 0) {
!         fprintf(stderr, "missing EOD in data stream (common occurence)\n");
        }
        return -2;
      }
--- 568,574 ----
          ;
  
        if (count != 0) {
!         fprintf(stderr, "missing EOD in data stream (common occurrence)\n");
        }
        return -2;
      }
***************
*** 656,662 ****
  
    initLWZ(c);
  
!   fprintf(stderr, "reading %d by %d%s GIF image\n",
            width, height, interlace ? " interlaced" : "" );
  
    allocate_image();
--- 663,670 ----
  
    initLWZ(c);
  
!   if (!quiet)
!     fprintf(stderr, "reading %d by %d%s GIF image\n",
            width, height, interlace ? " interlaced" : "" );
  
    allocate_image();
diff -c gif2png-0.6/version.c gif2png-0.7/version.c
*** gif2png-0.6/version.c	Thu Nov  2 21:47:44 1995
--- gif2png-0.7/version.c	Sun Sep  5 12:39:25 1999
***************
*** 5,22 ****
   */
  
  
  #ifndef PNGLIB
! #define PNGLIB "pnglib (unknown version)"
  #endif
  #ifndef ZLIB
! #define ZLIB "zlib (unknown version)"
  #endif
  
! const char version[]="gif2png 0.6 (beta)";
  
  const char compile_info[]=
  #ifdef TMPFILE
! "(TMPFILE) "
  #endif
- "compiled " __DATE__ " with " PNGLIB " and " ZLIB;
- 
--- 5,28 ----
   */
  
  
+ #include "zlib.h"
+ #include "png.h"
+ 
  #ifndef PNGLIB
! #  define PNGLIB "pnglib (unknown version)"
  #endif
  #ifndef ZLIB
! #  define ZLIB "zlib (unknown version)"
  #endif
  
! const char version[]="gif2png 0.7,";
  
  const char compile_info[]=
  #ifdef TMPFILE
!   "(TMPFILE) "
! #endif
! #if defined(PNG_LIBPNG_VER_STRING) && defined(ZLIB_VERSION)
!   "compiled " __DATE__ " with libpng " PNG_LIBPNG_VER_STRING " and zlib " ZLIB_VERSION ".";
! #else
!   "compiled " __DATE__ " with " PNGLIB " and " ZLIB ".";
  #endif