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package Koha::CoverGenerator; |
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# Copyright 2022 LMSCloud GmbH |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it |
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# under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Koha is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Koha; if not, see <http://www.gnu.org/licenses>. |
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|
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use 5.032; |
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|
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use utf8; |
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use strict; |
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use warnings; |
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use Modern::Perl; |
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|
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our $VERSION = 1.0.0; |
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|
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use GD::Image; |
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use GD::Text::Align; |
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use MIME::Base64; |
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use Koha::Exceptions; |
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use Try::Tiny; |
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|
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=head1 NAME |
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|
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Koha::CoverGenerator - generate images as substitutes for missing cover images based |
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on two input strings. |
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|
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=head1 SYNOPSIS |
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|
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use Koha::CoverGenerator; |
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|
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=head1 DESCRIPTION |
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|
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This module provides a public to draw an image based on two input |
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strings through GD::Image and GD::Text::Align. |
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|
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The module returns a base64 encoded string, that can be used as a |
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data url in JavaScript. |
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|
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=head1 FUNCTIONS |
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|
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=head2 render_image( $args ) |
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|
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my $args = { |
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first_line => $first_line, |
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second_line => $second_line, |
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font => $font, |
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font_path => $font_path, |
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width => $width, |
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height => $height, |
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fontsize => $fontsize, |
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padding => $padding |
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format => $format, |
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} |
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|
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=over 4 |
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|
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=item C<first_line> |
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|
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First and second line are the strings to be drawn on the canvas. |
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|
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=item C<second_line> |
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|
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First and second line are the strings to be drawn on the canvas. |
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|
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=item C<font> |
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The exact filename of the font to be used while omitting any extensions |
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like .ttf or .otf. |
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|
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=item C<font_path> |
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|
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The path to the fonts directory where $font is located. Don't forget the |
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'/' at the end of the path. |
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|
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=item C<width> |
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|
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Width of the canvas. |
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|
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=item C<height> |
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|
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Height of the canvas. |
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|
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=item C<fontsize> |
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|
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Fontsize of the text drawn to the canvas. |
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|
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=item C<padding> |
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|
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Padding of the text drawn to the canvas. |
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|
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=back |
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|
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=cut |
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|
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use constant { |
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TWO => 2, |
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SIX => 6, |
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|
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RED => 244, |
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GREEN => 244, |
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BLUE => 244, |
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}; |
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|
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use constant SPACE => q{ }; |
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use constant EMPTY => q{}; |
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|
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my @leftover_words = EMPTY; |
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my $leftover_words = EMPTY; |
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|
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sub new { |
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my ( $class, $args ) = @_; |
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my $self = bless { |
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first_line => { string => $args->{'first_line'}, }, |
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second_line => { string => $args->{'second_line'}, }, |
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font => { |
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name => $args->{'font'}, |
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path => $args->{'font_path'}, |
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size => $args->{'fontsize'}, |
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}, |
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dimensions => { |
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width => $args->{'width'}, |
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height => $args->{'height'}, |
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padding => $args->{'padding'}, |
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content_width => $args->{'width'} - $args->{'padding'}, |
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}, |
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positions => { |
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horizontal_center => $args->{'width'} / TWO, |
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vertical_top => $args->{'height'} / SIX, |
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vertical_bottom => $args->{'height'} / TWO, |
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}, |
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image => GD::Image->new( $args->{'width'}, $args->{'height'} ), |
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format => $args->{'format'}, |
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}, $class; |
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|
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$self->{'image'}->trueColor(1); |
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$self->{'image'}->colorAllocate( RED, GREEN, BLUE ); |
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$self->{'font'}->{'color'} = $self->{'image'}->colorAllocate( 0, 0, 0 ); |
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|
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$self->{'align'} = GD::Text::Align->new( |
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$self->{'image'}, |
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valign => 'center', |
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halign => 'center', |
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color => $self->{'font'}->{'color'}, |
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); |
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$self->{'align'}->font_path( $args->{'font_path'} ); |
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|
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return $self; |
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|
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} |
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|
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sub get_string_width_by_params { |
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my ( $class, $args ) = @_; |
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|
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if ( !defined $class->{'align'} ) { |
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Koha::Exceptions::MissingParameter->throw('image is undefined as parameter in get_string_width_by_params'); |
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} |
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$class->{'align'}->set_font( $class->{'font'}->{'name'}, $args->{'fontsize'} || $class->{'font'}->{'size'} ); |
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$class->{'align'}->set_text( $args->{'string'} ); |
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return $class->{'align'}->get('width'); |
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} |
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sub trim_string { |
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my ( $class, $args ) = @_; |
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|
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# turning point for the trim_string function. |
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if ( $args->{'string'} eq $leftover_words ) { |
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$leftover_words = EMPTY; |
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} |
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# Break the string on spaces and assign to array. |
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my @words = split SPACE, $args->{'string'}; |
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# Pop the last word and store in leftovers. |
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$leftover_words .= pop(@words) . SPACE; |
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# Set the return value to empty string. |
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my $new_line = EMPTY; |
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|
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# Append the remaining words to the return value. |
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for my $word (@words) { |
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$new_line .= "$word "; |
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} |
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# Check if the new line fits into the box. |
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my $new_string_width = $class->get_string_width_by_params( { string => $new_line } ); |
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# If it does, return the new line and handle the leftovers. |
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if ( $new_string_width <= $class->{'dimensions'}->{'content_width'} ) { |
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return $new_line; |
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} |
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# If a single word is bigger than the box, we have to prevent an infinite loop. |
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if ( $new_string_width > $class->{'dimensions'}->{'content_width'} |
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&& scalar @words == 1 ) |
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{ |
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return $new_line; |
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} |
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# If it doesn't, repeat the process until it does. |
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return $class->trim_string( { string => $new_line, } ); |
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} |
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sub format_string { |
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my ( $class, $args ) = @_; |
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my $string_width = $class->get_string_width_by_params( { string => $args->{'string'} } ); |
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if ( $string_width <= $class->{'dimensions'}->{'content_width'} ) { |
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return $args->{'string'}; |
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} |
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my $return_value; |
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my $formatted_string = EMPTY; |
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|
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$return_value = $class->trim_string( { string => $args->{'string'}, } ); |
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$formatted_string .= "$return_value\n"; |
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# reverse order of the leftovers before entering the while loop. |
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@leftover_words = reverse split SPACE, $leftover_words; |
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$leftover_words = EMPTY; |
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|
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for my $word (@leftover_words) { |
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$leftover_words .= "$word "; |
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} |
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while ( !$leftover_words eq EMPTY ) { |
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$return_value = EMPTY; |
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$return_value = $class->trim_string( { string => $leftover_words, } ); |
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$formatted_string .= "$return_value\n"; |
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@leftover_words = reverse split SPACE, $leftover_words; |
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$leftover_words = EMPTY; |
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for my $word (@leftover_words) { |
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$leftover_words .= "$word "; |
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} |
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my $new_string_width = $class->get_string_width_by_params( { string => $leftover_words } ); |
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if ( $new_string_width <= $class->{'dimensions'}->{'content_width'} ) { |
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$formatted_string .= "$leftover_words\n"; |
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$leftover_words = EMPTY; |
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} |
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if ( $new_string_width > $class->{'dimensions'}->{'content_width'} |
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&& scalar @leftover_words == 1 ) |
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{ |
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$formatted_string .= "$leftover_words\n"; |
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$leftover_words = EMPTY; |
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} |
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|
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} |
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return $formatted_string; |
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|
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} |
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|
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sub draw_text { |
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my ( $class, $args ) = @_; |
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|
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my $result_string = $class->format_string( { string => $args->{'content_string'}, } ); |
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my $new_image_width = $class->get_string_width_by_params( { string => $result_string, } ); |
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my $new_fontsize = 0; |
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while ( $new_image_width > $class->{'dimensions'}->{'content_width'} ) { |
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if ( !$new_fontsize ) { |
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$new_fontsize = $class->{'font'}->{'size'} - 2; |
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} |
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$class->{'align'}->set_font( $class->{'font'}->{'name'}, $new_fontsize ); |
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$new_image_width = $class->get_string_width_by_params( |
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{ fontsize => $new_fontsize, |
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string => $result_string |
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} |
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); |
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$new_fontsize -= 2; |
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} |
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|
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my @centered_result = split m/[\n]/xms, $result_string; |
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|
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my $index = 0; |
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for my $line (@centered_result) { |
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$class->{'align'}->set_text($line); |
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$class->{'align'}->draw( $class->{'positions'}->{'horizontal_center'}, $args->{'vertical_position'} + $index * ( $class->{'font'}->{'size'} + ( $class->{'font'}->{'size'} / 2 ) ), 0 ); |
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$index++; |
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} |
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|
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return; |
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} |
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sub render_image { |
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my $class = shift; |
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|
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if ( $class->{'first_line'}->{'string'} ) { |
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$class->draw_text( |
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{ content_string => $class->{'first_line'}->{'string'}, |
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vertical_position => $class->{'positions'}->{'vertical_top'}, |
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} |
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|
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); |
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} |
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|
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if ( $class->{'second_line'}->{'string'} ) { |
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$class->draw_text( |
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{ content_string => $class->{'second_line'}->{'string'}, |
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vertical_position => !$class->{'first_line'}->{'string'} |
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? $class->{'positions'}->{'vertical_top'} |
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: $class->{'positions'}->{'vertical_bottom'}, |
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} |
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|
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); |
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} |
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|
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my $formats = { |
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'jpeg' => sub { return encode_base64( $class->{'image'}->jpeg ) }, |
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'png' => sub { return encode_base64( $class->{'image'}->png ) }, |
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'gif' => sub { return encode_base64( $class->{'image'}->gif ) }, |
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}; |
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|
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return $formats->{ $class->{'format'} }->(); |
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} |
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|
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1; |
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