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package Imager::Font::Image;
use strict;
use Imager::Color;
use File::Basename;
use File::Spec;
use vars qw(@ISA %REQUIRED_FIELDS);
@ISA = qw(Imager::Font);
sub NWIDTH () { 0 }
sub PWIDTH () { 2 }
sub GDESCENT () { 1 }
sub GASCENT () { 3 }
sub DESCENT () { 4 }
sub ASCENT () { 5 }
%REQUIRED_FIELDS = (
Image_spec => 1,
Font_size => 1,
Global_ascent => 1,
Global_descent => 1,);
# Required fields
# Fontmetrics:
# Font global data:
# image name
# font size
# max glyph height
# max glyph width
#
# The per character data is:
# left edge (inclusive)
# right edge (exclusive)
# top edge (inclusive)
# bottom edge (exclusive)
# left adjustment
# forward shift
# baseline adjustment (from top)
#
# The left adjustment is the starting
# offset into the glyph, the forward shift
# is the actual forward movement of the
# imaginary cursor.
# To calculate the size of a string use:
# sum (forward_shift_i) + left_adjustment_0 + width_last - left_adjustment_last - forward_shift_last
# example font spec file:
# IAGRFONT
# # This is an imager font definition file. This is a comment
# Image_spec = foo.png
# Font_size = 12
# Global_ascent = 10
# Global_descent = -2
# # Per character data
# FM_65 = 20 40 30 50 3 15
# # Code for 'A' left edge = 20, right = 40, top = 30, bottom 50, leading = 3, forward = 15.
# The left adjustment is the starting
# offset into the glyph, the forward shift
# is the actual forward movement of the
# imaginary cursor.
# To calculate the size of a string use:
# sum (forward_shift_i) + left_adjustment_0 + width_last - left_adjustment_last - forward_shift_last
sub parse_fontspec_file {
my ($self, $file) = @_;
local *FH;
return unless open(FH, "<$file");
my %req = %REQUIRED_FIELDS;
while(<FH>) {
next if m/^\#/;
if (m/^\s*?(\S+?)\s*=\s*(.+?)\s*$/) {
# Check for a required field:
my $char = $1;
my $metric = $2;
if ($req{$char}) {
$self->{$char} = $metric;
delete $req{$1};
} else {
next unless $char =~ s/^FM_(\d+)$/$1/;
next unless $metric =~ m/(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)$/;
$self->{fm}->{$char} = [$1, $2, $3, $4, $5, $6];
}
}
}
close(FH);
return $self;
}
sub new {
my $self = bless {}, shift;
my %opts = (color=>Imager::Color->new(255, 0, 0, 0), @_);
unless ($opts{file}) {
$Imager::ERRSTR = "No font file specified";
return;
}
unless ($self->parse_fontspec_file($opts{file})) {
$Imager::ERRSTR = "Font file $opts{file} not found or bad";
return;
}
my $img = Imager->new();
my $img_filename = File::Spec->catfile( dirname($opts{'file'}),
$self->{Image_spec} );
unless ($img->open(%opts, file=>$img_filename)) {
$Imager::ERRSTR = "Font IMAGE file $img_filename not found or bad: ".
$img->errstr();
return;
}
$self->{image} = $img;
$self->{size} = $self->{Font_size};
return $self;
}
sub get_glyph_data {
my ($self, $glyph_code) = @_;
return unless exists $self->{fm}->{$glyph_code};
return @{$self->{fm}->{$glyph_code}};
}
# copy_glyph
#
# $x, $y is left, baseline for glyphs.
#
sub copy_glyph {
my ($self, $glyph_code, $target_img, $x, $y) = @_;
my @gdata = $self->get_glyph_data($glyph_code) or return;
$target_img->rubthrough(src=>$self->{image},
tx => $x + $gdata[4],
ty => $y - $self->{Global_ascent},,
src_minx => $gdata[0],
src_maxx => $gdata[1],
src_miny => $gdata[2],
src_maxy => $gdata[3]);
}
sub _draw {
my ($self, %opts) = @_;
my $x = $opts{'x'};
my $y = $opts{'y'};
my @glyphs = unpack("C*", $opts{string});
my $img = $opts{image};
my $glyph;
for $glyph (@glyphs) {
my @gmetrics = $self->get_glyph_data($glyph) or next;
$self->copy_glyph($glyph, $img, $x, $y);
$x += $gmetrics[5];
}
}
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