package Font::FNT;

our $VERSION = '0.02';

use strict;
use warnings;
use YAML();

my @Spec = qw
(
 n   Version
 L   Size
 Z60 Copyright
 S   Type
 S   Points
 S   VertRes
 S   HorizRes
 S   Ascent
 S   InternalLeading
 S   ExternalLeading
 C   Italic
 C   Underline
 C   StrikeOut
 S   Weight
 C   CharSet
 S   PixWidth
 S   PixHeight
 C   PitchAndFamily
 S   AvgWidth
 S   MaxWidth
 C   FirstChar
 C   LastChar
 C   DefaultChar
 C   BreakChar
 S   WidthBytes
 L   Device
 L   Face
 L   BitsPointer
 L   BitsOffset
 Z1  Reserved
 L   Flags
 S   Aspace
 S   Bspace
 S   Cspace
 L   ColorPointer
 Z16 Reserved1
);
my ( @k, @v );
for ( my $i = 0; $i < @Spec; $i += 2 )
{
  push @k, $Spec[$i+1];
  push @v, $Spec[$i+0];
}
# -----------------------------------------------------------------------------
sub load
# -----------------------------------------------------------------------------
{
  my $class = shift;
  my $File  = shift;
  my $self  = {};

  open my $f, $File or die $!;
  binmode $f;
  local $/;
  my $s = <$f>;
  my @a = unpack "@v A*", $s;
  my $Rest = pop @a;
  @$self{@k} = @a;

  $self->{FaceName} = unpack "x$self->{Face} Z*", $s;
  my $CharTableSize = $self->{LastChar} - $self->{FirstChar} + 2;
  my @CharTable = unpack 'SL' x $CharTableSize, $Rest;
  for ( 0 .. $CharTableSize - 2 )
  {
    my $Width  = $CharTable[2*$_];
    my $Offset = $CharTable[2*$_+1];
    my $Bytes  = $CharTable[2*$_+3] - $Offset;
    my $Char   = { Width => $Width, Code => $_ + $self->{FirstChar} };
    $self->{Chars}[$_] = $Char;
    my @Bmp = unpack "x$Offset C$Bytes", $s;
    my @Cmp;
    $Cmp[$_ % $self->{PixHeight}] .= sprintf '%08b', $Bmp[$_] for 0 .. $#Bmp;
    $_ = substr $_, 0, $Width for @Cmp;
    tr/01/-#/ for @Cmp;
    $Char->{BitMap} = \@Cmp;
  }
  bless $self, $class;
}
# -----------------------------------------------------------------------------
sub save
# -----------------------------------------------------------------------------
{
  my $self = shift;
  my $File = shift;

  my @CharTable;
  my $CharTableSize = $self->{LastChar} - $self->{FirstChar} + 2;
  my $BitsOffset    = 148 + $CharTableSize * 6;
  my $Offset        = $BitsOffset;
  my $Bits          = '';
  my $Sentinel      =
  {
    Width  =>          $self->{AvgWidth}
  , BitMap => [ ('-' x $self->{AvgWidth} ) x $self->{PixHeight} ]
  };
  for ( @{$self->{Chars}}, $Sentinel )
  {
    my @Bmp = @{$_->{BitMap}};
    tr/-#/01/ for @Bmp;
    my $Bmp;
    for ( my $Offset = 0; $Offset < $_->{Width}; $Offset += 8 )
    {
      $Bmp .= pack 'B8', substr $_, $Offset for @Bmp;
    }
    push @CharTable, $_->{Width};
    push @CharTable, $Offset;
    $Offset += length $Bmp;
    $Bits .= $Bmp;
  }
  $self->{BitsOffset} = $BitsOffset;
  $self->{Face}       = $Offset;
  $self->{Size}       = $Offset + length( $self->{FaceName} ) + 1;

  my $s  = pack "@v", @$self{@k};
     $s .= pack 'SL' x $CharTableSize, @CharTable;
     $s .= $Bits;
     $s .= pack 'Z*', $self->{FaceName};

  open my $f, ">$File" or die $!;
  binmode $f;
  print $f $s;
}
# -----------------------------------------------------------------------------
sub save_yaml
# -----------------------------------------------------------------------------
{
  my $self = shift;
  my $File = shift;

  local $YAML::Indent = 1;

  YAML::DumpFile( $File, $self );
}
# -----------------------------------------------------------------------------
sub load_yaml
# -----------------------------------------------------------------------------
{
  my $class = shift;
  my $File  = shift;

  my $self  = YAML::LoadFile( $File );

  bless $self, $class;
}
# -----------------------------------------------------------------------------
sub save_pbm
# -----------------------------------------------------------------------------
{
  my $self = shift;
  my $File = shift;

  open my $f,'>', $File or die "Failed to open `$File': $!";

  my $Width = 0;
     $Width += length $_->{BitMap}[0] for @{$self->{Chars}};
  local $\ = "\n";
  print $f 'P1';
  print $f $Width;
  print $f $self->{PixHeight};
  local $\ = '';

  for my $y ( 0 .. $self->{PixHeight} - 1 )
  {
    for ( @{$self->{Chars}} )
    {
      my $s = $_->{BitMap}[$y];
      $s =~ tr/-#/01/;;
      print $f $s;
    }
    print $f "\n";
  }
}
# -----------------------------------------------------------------------------
1;

=head1 NAME

Font::FNT - Load, manipulate and save Windows raster fonts

=head1 SYNOPSIS

  use Font::FNT();


  my $fnt = Font::FNT->load('test.fnt');

  $fnt->save_yaml('test.yml');


  # scite test.yml


  $fnt = Font::FNT->load_yaml('test.yml');

  $fnt->save_pbm('test.pbm');


  $fnt->save('test.fnt');

=head1 DESCRIPTION

This module provides basic load, manipulate and save functionality for
Windows 3.00 raster fonts (.FNT files).

=head2 Methods

=over

=item load( $filename )

Loads a .FNT file. This is a constructor method and returns an
Font::FNT instance.

=item save_yaml( $filename )

Saves a Font::FNT instance into a notepadable format (YAML).
You can use your prefered text editor to manipulate that serialized
Font::FNT instance.

=item load_yaml( $filename )

Loads a YAML file (which should contain a serialized Font::FNT instance).
This is a constructor method and returns an Font::FNT instance.

=item save_pbm( $filename )

Saves a Font::FNT instance as portable bitmap (pbm) file.
Yo can use this for preview purposes.

=item save( $filename )

Saves a Font::FNT instance as .FNT file.

=back

=head1 EXAMPLE

The test directory contains a serialized Font::FNT instance
(1252_13x8_OEM.yml) that can be used to install a nice Console
(Terminal) font - at least on a Windows NT 4.0 box.
Other Windows versions may require other steps.

The font is similar to the bold BorlandTE font (BORTE.FON) or
Raize font.

Let's create the .FNT file first:

  use Font::FNT();
  Font::FNT->load_yaml('t/1252_13x8_OEM.yml')->save('t/1252_13x8_OEM.fnt');

Normally, various .FNT files for different sizes and weights are
packaged together as resources in a Windows DLL (.FON file).
BTW: most .FON files are good old Windows 3.1 DLLs.
For our purpose, the .FNT file is o.k.

Next, add something like

  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts]
  "1252 13x8 OEM"="1252_13x8_OEM.fnt"

to your registry, copy the font by hand

  copy t\1252_13x8_OEM.fnt %SystemRoot%\Fonts

and reboot your system.

If you don't need control about your registry entries, then
you can simply drag'n drop t/1252_13x8_OEM.fnt into the Fonts
Control Panel Applet.

Now, if you open the Console properties dialog or the Console
Control Panel Applet, go to the font tab and select 'Raster Fonts',
you should see a new entry in the 'Size' listbox:

  8 x 13

Configuring the font in the Control Panel results in the following
registry entries:

  [HKEY_CURRENT_USER\Console]
  "FaceName"="Terminal"
  "FontSize"=dword:000d0008

Finally, you should change the Console codepage:

  mode con cp select=1252

or

  chcp 1252

To change the codepage permanently, add the following to your
registry:

  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage]
  "OEMCP"="1252"


=head1 AUTHOR

Steffen Goeldner <sgoeldner@cpan.org>

=head1 COPYRIGHT

Copyright (c) 2004 Steffen Goeldner. All rights reserved.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 SEE ALSO

=head2 Microsoft Knowledge Base Article

=over

=item Windows Developers Notes: Font-File Format

  http://support.microsoft.com/?scid=kb;EN-US;65123

=item MyFont.exe - Creating a Custom Raster Font

  http://support.microsoft.com/?scid=kb;EN-US;76535

=item Necessary Criteria for Fonts to Be Available in a Command Window

  http://support.microsoft.com/?scid=kb;EN-US;247815

=item How to Change the OEM Code Page of Windows NT and Windows 95

  http://support.microsoft.com/?scid=kb;EN-US;153449

=back

=head2 Microsoft Global Development and Computing Portal - Code Pages

  http://www.microsoft.com/globaldev/reference/cphome.mspx

=head2 Adobe Glyph Bitmap Distribution Format (BDF) Specification

  http://partners.adobe.com/asn/developer/pdfs/tn/5005.BDF_Spec.pdf

This format is similar in spirit to the YAML serialization of a
Font::FNT instance.

=head2 Perl modules

L<perl>, L<YAML>, L<Image::Pbm>.

=cut