package SVG::SVG2zinc::Backend; # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU LGPL Libray General Public License # as published by the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU Library General Public License for more details. # # You should have received a copy of the GNU Library General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA, # or refer to http://www.gnu.org/copyleft/lgpl.html # ################################################################## # Backend for SVG2zinc # # Copyright 2003-2004 # Centre d'?tudes de la Navigation A?rienne # # Author: Christophe Mertz # # An abstract class for code generation # Concrete sub-classes can generate code for perl (script / module), tcl, # printing, or direct execution # # $Id: Backend.pm,v 1.1.1.2 2006-11-16 14:51:45 merlin Exp $ ############################################################################# use strict; use Carp; use FileHandle; use vars qw( $VERSION); ($VERSION) = sprintf("%d.%02d", q$Revision: 1.1.1.2 $ =~ /(\d+)\.(\d+)/); sub new { my ($class, %passed_options) = @_; my $self = {}; bless $self, $class; $self->_initialize(%passed_options); return $self; } my %new_options = ( -render => 1, -out => 1, -in => 1, -verbose => 1, ); sub _initialize { my ($self, %passed_options) = @_; foreach my $opt (keys (%passed_options)) { if (defined ($new_options{$opt})) { $self->{$opt} = $passed_options{$opt}; } else { carp ("Warning: option $opt unknown for a ".ref($self)."\n"); } } $self -> {-render} = 1 unless defined $self -> {-render}; croak("undefined mandatory -in options") unless defined $self -> {-in}; if (defined $self -> {-out} and $self -> {-out}) { my $out = $self->{-out}; if (ref($out) eq 'GLOB') { ## nothing to do, the $out is supposed to be open!? } else { my @reps = split ('::', $out); my $file = $reps [0]; for (my $i = 0; $i < @reps - 1; $i++) { if(not -d $file) { if(system("mkdir -p $file")) { print STDERR "##### Error creating directory: $file\n"; } } $file .= '/'.$reps [$i + 1]; } print STDERR "writing $file...\n"; my $fh = FileHandle -> new("> " . $file); if ($fh) { $self->{-filehandle} = $fh; } else { carp ("unable to open " . $out); } } } return $self; } # used by SVG2zinc to know the zinc group in which the svg topgroup # by default: 1 # currently default need be overriden by PerlClass only, as far as I now!? sub _topgroup { my ($self) = @_; if ($self->{-topgroup}) { return $self->{-topgroup}; } else { return 1; } } # returns true if code is put in a file sub inFile { my ($self) = @_; return (defined $self->{-filehandle}); } sub printLines { my ($self, @lines) = @_; if ($self->inFile) { my $fh = $self->{-filehandle}; foreach my $l (@lines) { print $fh "$l\n"; } } else { carp "printLines cannot print if no outfile has been given\n"; } } sub treatLines { my ($self, @lines) = @_; if ($self->inFile) { $self->printLines(@lines); } } ## in case of file generation, should print a comment ## the default is to print comment starting with # sub comment { my ($self, @lines) = @_; if ($self->inFile) { foreach my $l (@lines) { $self->printLines("## $l"); } } } sub close { my ($self) = @_; if ($self->inFile) { $self->{-filehandle}->close; } } sub fileHeader { my ($self) = @_; $self->comment ("", "default Header of SVG::SVG2zinc::Backend", ""); } sub fileTail { my ($self) = @_; $self->comment ("", "default Tail of SVG::SVG2zinc::Backend", ""); $self->close; } 1; __END__ =head1 NAME SVG::SVG2zinc::Backend - a virtual class SVG::SVG2zinc svg reader. Sub-class are specialized for different type of generation =head1 SYNOPSIS package SVG::SVG2zinc::Backend::SubClass use SVG::SVG2zinc::Backend; ## some methods definition .... ## when using a specialized backend: use SVG::SVG2zinc::Backend::SubClass; $backend = SVG::SVG2zinc::Backend::SubClass->new( -out => filename_or_handle, -in => svgfilename, -verbose => 0|1, [otheroptions], ); $backend->fileHeader(); $backend->treatLines("lineOfCode1", "lineOfCode2",...); $backend->comment("comment1", "comment2", ...); $backend->printLines("comment1", "comment2", ...); $backend->fileTail(); =head1 DESCRIPTION SVG::SVG2zinc::Backend is a perl virtual class which should be specialized in sub-classes. It defines a common interface ot classes which can for example generate perl code with Tk::Zinc, display SVG file in a Tk::Zinc widget, convert svg file in image files (e.g. png) or generate tcl code to be used with TkZinc etc... A backend should provide the following methods: =over =item B This creation class method should accept pairs of (-option => value) as well as the following arguments: =over =item B<-out> A filename or a filehandle ready for writing the output. In same rare cases (e.g. the Display backend which only displays the SVG file on the screen, this option will not be used) =item B<-in> The svg filename. It should be used in comments only in the generated file =item B<-verbose> It will be used for letting the backend being verbose =back =item B Generates the header in the out file, if needed. This method should be called just after creating a backend and prior any treatLines or comment method call. =item B Processes the given arguments as lines of code. The arguments are very close to Tk::Zinc perl code. When creating a new backend, using the B backend can help understanding what are exactly these arguments. =item B Processes the given arguments as comments. Depending on the backend, this method must be redefined so that arguments are treated as comments, or just skipped. =item B Print in an outfile the given arguments as lines of text. This method should not be re-defined, but used by any Backend which generates code. =item B Generate the tail in the out file if needed and closes the out file. This must be the last call. =back A backend can use the printLines method to print lines in the generated file. =head1 SEE ALSO SVG::SVG2zinc::Backend::Display(3pm), SVG::SVG2zinc::Backend::PerlScript(3pm), SVG::SVG2zinc::Backend::TclScript(3pm), SVG::SVG2zinc::Backend::PerlClass(3pm) code as examples of SVG::SVG2zinc::Backend subclasses. SVG::SVG2zinc(3pm) =head1 AUTHORS Christophe Mertz with some help from Daniel Etienne =head1 COPYRIGHT CENA (C) 2003-2004 This program is free software; you can redistribute it and/or modify it under the term of the LGPL licence. =cut