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- #!/usr/bin/perl
- ## $Id: ppmtolss16,v 1.12 2004/12/14 23:03:28 hpa Exp $
- ## -----------------------------------------------------------------------
- ##
- ## Copyright 2004 H. Peter Anvin - All Rights Reserved
- ##
- ## This program is free software; you can redistribute it and/or modify
- ## it under the terms of the GNU General Public License as published by
- ## the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- ## Boston MA 02111-1307, USA; either version 2 of the License, or
- ## (at your option) any later version; incorporated herein by reference.
- ##
- ## -----------------------------------------------------------------------
-
- ##
- ## ppmtolss16
- ##
- ## Convert a PNM file with max 16 colors to a simple RLE-based format:
- ##
- ## uint32 0x1413f33d ; magic (littleendian)
- ## uint16 xsize ; littleendian
- ## uint16 ysize ; littleendian
- ## 16 x uint8 r,g,b ; color map, in 6-bit format (each byte is 0..63)
- ##
- ## Then, a sequence of nybbles:
- ##
- ## N ... if N is != previous pixel, one pixel of color N
- ## ... otherwise run sequence follows ...
- ## M ... if M > 0 then run length is M+1
- ## ... otherwise run sequence is encoded in two nybbles,
- ## littleendian, +17
- ##
- ## The nybble sequences are on a per-row basis; runs may not extend
- ## across rows and odd-nybble rows are zero-padded.
- ##
- ## At the start of row, the "previous pixel" is assumed to be zero.
- ##
- ## Usage:
- ##
- ## ppmtolss16 [#rrggbb=i ...] < input.ppm > output.rle
- ##
- ## Command line options of the form #rrggbb=i indicate that
- ## the color #rrggbb (hex) should be assigned index i (decimal)
- ##
-
- eval { use bytes; };
- eval { binmode STDIN; };
- eval { binmode STDOUT; };
-
- $magic = 0x1413f33d;
-
- # Get a token from the PPM header. Ignore comments and leading
- # and trailing whitespace, as is required by the spec.
- # This routine eats exactly one character of trailing whitespace,
- # unless it is a comment (in which case it eats the comment up
- # to and including the end of line.)
- sub get_token() {
- my($token, $ch);
- my($ch);
-
- do {
- $ch = getc(STDIN);
- return undef if ( !defined($ch) ); # EOF
- if ( $ch eq '#' ) {
- do {
- $ch = getc(STDIN);
- return undef if ( !defined($ch) );
- } while ( $ch ne "\n" );
- }
- } while ( $ch =~ /^[ \t\n\v\f\r]$/ );
-
- $token = $ch;
- while ( 1 ) {
- $ch = getc(STDIN);
- last if ( $ch =~ /^[ \t\n\v\f\r\#]$/ );
- $token .= $ch;
- }
- if ( $ch eq '#' ) {
- do {
- $ch = getc(STDIN);
- } while ( defined($ch) && $ch ne "\n" );
- }
- return $token;
- }
-
- # Get a token, and make sure it is numeric (and exists)
- sub get_numeric_token() {
- my($token) = get_token();
-
- if ( $token !~ /^[0-9]+$/ ) {
- print STDERR "Format error on input\n";
- exit 1;
- }
-
- return $token + 0;
- }
-
- # Must be called before each pixel row is read
- sub start_new_row() {
- $getrgb_leftover_bit_cnt = 0;
- $getrgb_leftover_bit_val = 0;
- }
-
- # Get a single RGB token depending on the PNM type
- sub getrgb($) {
- my($form) = @_;
- my($rgb,$r,$g,$b);
-
- if ( $form == 6 ) {
- # Raw PPM, most common
- return undef unless ( read(STDIN,$rgb,3) == 3 );
- return unpack("CCC", $rgb);
- } elsif ( $form == 3 ) {
- # Plain PPM
- $r = get_numeric_token();
- $g = get_numeric_token();
- $b = get_numeric_token();
- return ($r,$g,$b);
- } elsif ( $form == 5 ) {
- # Raw PGM
- return undef unless ( read(STDIN,$rgb,1) == 1 );
- $r = unpack("C", $rgb);
- return ($r,$r,$r);
- } elsif ( $form == 2 ) {
- # Plain PGM
- $r = get_numeric_token();
- return ($r,$r,$r);
- } elsif ( $form == 4 ) {
- # Raw PBM
- if ( !$getrgb_leftover_bit_cnt ) {
- return undef unless ( read(STDIN,$rgb,1) == 1 );
- $getrgb_leftover_bit_val = unpack("C", $rgb);
- $getrgb_leftover_bit_cnt = 8;
- }
- $r = ( $getrgb_leftover_bit_val & 0x80 ) ? 0x00 : 0xff;
- $getrgb_leftover_bit_val <<= 1;
- $getrgb_leftover_bit_cnt--;
-
- return ($r,$r,$r);
- } elsif ( $form == 1 ) {
- # Plain PBM
- my($ch);
-
- do {
- $ch = getc(STDIN);
- return undef if ( !defined($ch) );
- return (255,255,255) if ( $ch eq '0' ); # White
- return (0,0,0) if ( $ch eq '1'); # Black
- if ( $ch eq '#' ) {
- do {
- $ch = getc(STDIN);
- return undef if ( !defined($ch) );
- } while ( $ch ne "\n" );
- }
- } while ( $ch =~ /^[ \t\n\v\f\r]$/ );
- return undef;
- } else {
- die "Internal error: unknown format: $form\n";
- }
- }
-
- sub rgbconvert($$$$) {
- my($r,$g,$b,$maxmult) = @_;
- my($rgb);
-
- $r = int($r*$maxmult);
- $g = int($g*$maxmult);
- $b = int($b*$maxmult);
- $rgb = pack("CCC", $r, $g, $b);
- return $rgb;
- }
-
- foreach $arg ( @ARGV ) {
- if ( $arg =~ /^\#([0-9a-f])([0-9a-f])([0-9a-f])=([0-9]+)$/i ) {
- $r = hex($1) << 4;
- $g = hex($2) << 4;
- $b = hex($3) << 4;
- $i = $4 + 0;
- } elsif ( $arg =~ /^\#([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})=([0-9]+)$/i ) {
- $r = hex($1);
- $g = hex($2);
- $b = hex($3);
- $i = $4 + 0;
- } elsif ( $arg =~ /^\#([0-9a-f]{3})([0-9a-f]{3})([0-9a-f]{3})=([0-9]+)$/i ) {
- $r = hex($1) >> 4;
- $g = hex($2) >> 4;
- $b = hex($3) >> 4;
- $i = $4 + 0;
- } elsif ( $arg =~ /^\#([0-9a-f]{4})([0-9a-f]{4})([0-9a-f]{4})=([0-9]+)$/i ) {
- $r = hex($1) >> 8;
- $g = hex($2) >> 8;
- $b = hex($3) >> 8;
- $i = $4 + 0;
- } else {
- print STDERR "$0: Unknown argument: $arg\n";
- next;
- }
-
- if ( $i > 15 ) {
- print STDERR "$0: Color index out of range: $arg\n";
- next;
- }
-
- $rgb = rgbconvert($r, $g, $b, 64/256);
-
- if ( defined($index_forced{$i}) ) {
- print STDERR "$0: More than one color index $i\n";
- exit(1);
- }
- $index_forced{$i} = $rgb;
- $force_index{$rgb} = $i;
- }
-
- $form = get_token();
- die "$0: stdin is not a PNM file" if ( $form !~ /^P([1-6])$/ );
- $form = $1+0;
-
- $xsize = get_numeric_token();
- $ysize = get_numeric_token();
- if ( $form == 1 || $form == 4 ) {
- $maxcol = 255; # Internal convention
- } else {
- $maxcol = get_numeric_token();
- }
- $maxmult = 64/($maxcol+1); # Equal buckets conversion
-
- @data = ();
-
- for ( $y = 0 ; $y < $ysize ; $y++ ) {
- start_new_row();
- for ( $x = 0 ; $x < $xsize ; $x++ ) {
- die "$0: Premature EOF at ($x,$y) of ($xsize,$ysize)\n"
- if ( !defined(@pnmrgb = getrgb($form)) );
- # Convert to 6-bit representation
- $rgb = rgbconvert($pnmrgb[0], $pnmrgb[1], $pnmrgb[2], $maxmult);
- $color_count{$rgb}++;
- push(@data, $rgb);
- }
- }
-
- # Sort list of colors according to freqency
- @colors = sort { $color_count{$b} <=> $color_count{$a} } keys(%color_count);
-
- # Now we have our pick of colors. Sort according to intensity;
- # this is more or less an ugly hack to cover for the fact that
- # using PPM as input doesn't let the user set the color map,
- # which the user really needs to be able to do.
-
- sub by_intensity() {
- my($ra,$ga,$ba) = unpack("CCC", $a);
- my($rb,$gb,$bb) = unpack("CCC", $b);
-
- my($ia) = $ra*0.299 + $ga*0.587 + $ba*0.114;
- my($ib) = $rb*0.299 + $gb*0.587 + $bb*0.114;
-
- return ( $ia <=> $ib ) if ( $ia != $ib );
-
- # If same, sort based on RGB components,
- # with highest priority given to G, then R, then B.
-
- return ( $ga <=> $gb ) if ( $ga != $gb );
- return ( $ra <=> $rb ) if ( $ra != $rb );
- return ( $ba <=> $bb );
- }
-
- @icolors = sort by_intensity @colors;
-
- # Insert forced colors into "final" array
- @colors = (undef) x 16;
- foreach $rgb ( keys(%force_index) ) {
- $i = $force_index{$rgb};
- $colors[$i] = $rgb;
- $color_index{$rgb} = $i;
- }
-
- undef %force_index;
-
- # Insert remaining colors in the remaining slots,
- # in luminosity-sorted order
- $nix = 0;
- while ( scalar(@icolors) ) {
- # Advance to the next free slot
- $nix++ while ( defined($colors[$nix]) && $nix < 16 );
- last if ( $nix >= 16 );
- $rgb = shift @icolors;
- if ( !defined($color_index{$rgb}) ) {
- $colors[$nix] = $rgb;
- $color_index{$rgb} = $nix;
- }
- }
-
- while ( scalar(@icolors) ) {
- $rgb = shift @icolors;
- $lost++ if ( !defined($color_index{$rgb}) );
- }
-
- if ( $lost ) {
- printf STDERR
- "$0: Warning: color palette truncated (%d colors ignored)\n", $lost;
- }
-
- undef @icolors;
-
- # Output header
- print pack("Vvv", $magic, $xsize, $ysize);
-
- # Output color map
- for ( $i = 0 ; $i < 16 ; $i++ ) {
- if ( defined($colors[$i]) ) {
- print $colors[$i];
- } else {
- # Padding for unused color entries
- print pack("CCC", 63*$i/15, 63*$i/15, 63*$i/15);
- }
- }
-
- sub output_nybble($) {
- my($ny) = @_;
-
- if ( !defined($ny) ) {
- if ( defined($nybble_tmp) ) {
- $ny = 0; # Force the last byte out
- } else {
- return;
- }
- }
-
- $ny = $ny & 0x0F;
-
- if ( defined($nybble_tmp) ) {
- $ny = ($ny << 4) | $nybble_tmp;
- print chr($ny);
- $bytes++;
- undef $nybble_tmp;
- } else {
- $nybble_tmp = $ny;
- }
- }
-
- sub output_run($$$) {
- my($last,$this,$run) = @_;
-
- if ( $this != $last ) {
- output_nybble($this);
- $run--;
- }
- while ( $run ) {
- if ( $run >= 16 ) {
- output_nybble($this);
- output_nybble(0);
- if ( $run > 271 ) {
- $erun = 255;
- $run -= 271;
- } else {
- $erun = $run-16;
- $run = 0;
- }
- output_nybble($erun);
- output_nybble($erun >> 4);
- } else {
- output_nybble($this);
- output_nybble($run);
- $run = 0;
- }
- }
- }
-
- $bytes = 0;
- undef $nybble_tmp;
-
- for ( $y = 0 ; $y < $ysize ; $y++ ) {
- $last = $prev = 0;
- $run = 0;
- for ( $x = 0 ; $x < $xsize ; $x++ ) {
- $rgb = shift(@data);
- $i = $color_index{$rgb} + 0;
- if ( $i == $last ) {
- $run++;
- } else {
- output_run($prev, $last, $run);
- $prev = $last;
- $last = $i;
- $run = 1;
- }
- }
- # Output final datum for row; we're always at least one pixel behind
- output_run($prev, $last, $run);
- output_nybble(undef); # Flush row
- }
-
- $pixels = $xsize * $ysize;
- $size = ($pixels+1)/2;
- printf STDERR "%d pixels, %d bytes, (%2.2f%% compression)\n",
- $pixels, $bytes, 100*($size-$bytes)/$size;
-
-
-
-
-