1package Imager::Font::Image;
2use 5.006;
3use strict;
4use Imager::Color;
5use File::Basename;
6use File::Spec;
7
8our @ISA = qw(Imager::Font);
9our $VERSION = "1.000";
10
11sub NWIDTH   () { 0 }
12sub PWIDTH   () { 2 }
13sub GDESCENT () { 1 }
14sub GASCENT  () { 3 }
15sub DESCENT  () { 4 }
16sub ASCENT   () { 5 }
17
18
19our %REQUIRED_FIELDS = (
20	Image_spec     => 1,
21	Font_size      => 1,
22	Global_ascent  => 1,
23	Global_descent => 1,);
24
25# Required fields
26# Fontmetrics:
27# Font global data:
28#   image name
29#   font size
30#   max glyph height
31#   max glyph width
32#
33# The per character data is:
34#   left edge   (inclusive)
35#   right edge  (exclusive)
36#   top edge    (inclusive)
37#   bottom edge (exclusive)
38#   left adjustment
39#   forward shift
40#   baseline adjustment (from top)
41#
42# The left adjustment is the starting
43# offset into the glyph, the forward shift
44# is the actual forward movement of the
45# imaginary cursor.
46
47# To calculate the size of a string use:
48#  sum (forward_shift_i) + left_adjustment_0 + width_last - left_adjustment_last - forward_shift_last
49
50# example font spec file:
51
52# IAGRFONT
53# # This is an imager font definition file.  This is a comment
54# Image_spec = foo.png
55# Font_size  = 12
56# Global_ascent = 10
57# Global_descent = -2
58# # Per character data
59# FM_65 = 20 40 30 50 3 15
60# # Code for 'A' left edge = 20, right = 40, top = 30, bottom 50, leading = 3, forward = 15.
61# The left adjustment is the starting
62# offset into the glyph, the forward shift
63# is the actual forward movement of the
64# imaginary cursor.
65
66# To calculate the size of a string use:
67#  sum (forward_shift_i) + left_adjustment_0 + width_last - left_adjustment_last - forward_shift_last
68
69
70
71sub parse_fontspec_file {
72  my ($self, $file) = @_;
73  local *FH;
74  return unless open(FH, "<$file");
75
76  my %req = %REQUIRED_FIELDS;
77
78  while(<FH>) {
79    next if m/^\#/;
80    if (m/^\s*?(\S+?)\s*=\s*(.+?)\s*$/) {
81      # Check for a required field:
82      my $char = $1;
83      my $metric = $2;
84      if ($req{$char}) {
85	$self->{$char} = $metric;
86	delete $req{$1};
87      } else {
88	next unless $char =~ s/^FM_(\d+)$/$1/;
89	next unless $metric =~ m/(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)$/;
90	$self->{fm}->{$char} = [$1, $2, $3, $4, $5, $6];
91      }
92    }
93  }
94  close(FH);
95  return $self;
96}
97
98
99
100sub new {
101  my $self = bless {}, shift;
102  my %opts = (color=>Imager::Color->new(255, 0, 0, 0), @_);
103
104  unless ($opts{file}) {
105    $Imager::ERRSTR = "No font file specified";
106    return;
107  }
108  unless ($self->parse_fontspec_file($opts{file})) {
109    $Imager::ERRSTR = "Font file $opts{file} not found or bad";
110    return;
111  }
112
113  my $img = Imager->new();
114  my $img_filename = File::Spec->catfile( dirname($opts{'file'}),
115					  $self->{Image_spec} );
116
117  unless ($img->open(%opts, file=>$img_filename)) {
118    $Imager::ERRSTR = "Font IMAGE file $img_filename not found or bad: ".
119      $img->errstr();
120    return;
121  }
122
123  $self->{image} = $img;
124  $self->{size} = $self->{Font_size};
125  return $self;
126}
127
128sub get_glyph_data {
129  my ($self, $glyph_code) = @_;
130  return unless exists $self->{fm}->{$glyph_code};
131  return @{$self->{fm}->{$glyph_code}};
132}
133
134# copy_glyph
135#
136# $x, $y is left, baseline for glyphs.
137#
138
139sub copy_glyph {
140  my ($self, $glyph_code, $target_img, $x, $y) = @_;
141
142  my @gdata = $self->get_glyph_data($glyph_code) or return;
143
144  $target_img->rubthrough(src=>$self->{image},
145			  tx => $x + $gdata[4],
146			  ty => $y -  $self->{Global_ascent},,
147			  src_minx => $gdata[0],
148			  src_maxx => $gdata[1],
149			  src_miny => $gdata[2],
150			  src_maxy => $gdata[3]);
151}
152
153sub _draw {
154  my ($self, %opts) = @_;
155
156  my $x = $opts{'x'};
157  my $y = $opts{'y'};
158
159  my @glyphs = unpack("C*", $opts{string});
160  my $img = $opts{image};
161
162  my $glyph;
163  for $glyph (@glyphs) {
164    my @gmetrics = $self->get_glyph_data($glyph) or next;
165    $self->copy_glyph($glyph, $img, $x, $y);
166    $x += $gmetrics[5];
167  }
168}
169