addad P6 portable pixmap loader

diff --git a/scripts/evolis-driver.pl b/scripts/evolis-driver.pl
index 146f94a..811d420 100755 (executable)
--- a/scripts/evolis-driver.pl
+++ b/scripts/evolis-driver.pl
@@ -50,15 +50,46 @@ print "\x00" x 64; # FIXME some padding?
 sub read_pbm {
        my $path = shift;
        open(my $pbm, "pnmflip -rotate270 $path |");
-       my $p4 = <$pbm>; chomp $p4;
-       die "no P4 header in [$p4] from $path" unless $p4 eq 'P4';
+       my $magic = <$pbm>; chomp $magic;
        my $size = <$pbm>; chomp $size;
-       local $/ = undef;
-       my $data = <$pbm>;
-       warn "# $path $size ", length($data), " bytes\n";
-       if ( my $padding = ( 648 * 1016 / 8 - length($data) ) ) {
+       my $bitmap;
+       if ( $magic eq 'P4' ) { # portable bitmap
+               local $/ = undef;
+               $bitmap = <$pbm>;
+               warn "# $path $size ", length($bitmap), " bytes\n";
+       } elsif ( $magic eq 'P6' ) { # portable pixmap
+               my $max_color = <$pbm>; chomp $max_color;
+
+               my $trashold = $max_color / 2;
+
+               local $/ = undef;
+               my $rgb = <$pbm>;
+
+               my $mask = 0x80;
+               my $byte = 0;
+
+               my $o = 0;
+               while ( $o < length($rgb) ) {
+                       my $px = ord(substr($rgb,$o,1)); $o += 3;
+                       $byte ^= $mask if $px < $trashold;
+                       $mask >>= 1;
+                       if ( ! $mask ) { 
+                               $bitmap .= chr($byte);
+                               $byte = 0;
+                               $mask = 0x80;
+                       }
+               }
+
+               warn "# $path $size ", length($bitmap), " bytes\n";
+
+       } else {
+               die "unsupported $magic format!";
+       }
+
+       if ( my $padding = ( 648 * 1016 / 8 - length($bitmap) ) ) {
                warn "# adding $padding zero bytes padding\n";
-               $data .= "\x00" x $padding;
+               $bitmap .= "\x00" x $padding;
        }
-       return $data;
+
+       return $bitmap;
 }