File Coverage

blib/lib/HTML/Formatter.pm

Criterion	Covered	Total	%
statement	157	373	42.0
branch	24	62	38.7
condition	7	33	21.2
subroutine	50	153	32.6
pod	6	146	4.1
total	244	767	31.8

package HTML::Formatter;

# ABSTRACT: Base class for HTML formatters


use 5.006_001;
use strict;
use warnings;

use Carp;
use HTML::Element 3.15 ();

# We now use Smart::Comments in place of the old DEBUG framework.
# this should be commented out in release versions....
##use Smart::Comments;

our $VERSION = '2.06'; # VERSION
our $AUTHORITY = 'cpan:NIGELM'; # AUTHORITY

#
# A typical formatter will not use all of the features of this
# class.  But it will use some, as best fits the mapping
# of HTML to the particular output format.
#

# ------------------------------------------------------------------------


sub new {
    my ( $class, %arg ) = @_;

    my $self = bless { $class->default_values }, $class;
    $self->configure( \%arg ) if keys %arg;

    return $self;
}

# ------------------------------------------------------------------------
sub default_values {
    ();
}

# ------------------------------------------------------------------------
sub configure {
    my ( $self, $arg ) = @_;

    for ( keys %$arg ) {
        warn "Unknown configure argument '$_'" if $^W;
    }

    return $self;
}

# ------------------------------------------------------------------------
sub massage_tree {
    my ( $self, $html ) = @_;

    return if $html->tag eq 'p';    # sanity

    ### Before massaging: $html->dump()

    $html->simplify_pres();

    # Does anything else need doing?
    ### After massaging: $html->dump()

    return;
}

# ------------------------------------------------------------------------


sub format_from_file { return shift->format_file(@_); }

sub format_file {
    my ( $self, $filename, @params ) = @_;

    $self = $self->new(@params) unless ref $self;

    croak "What filename to format from?"
        unless ( defined($filename) and length($filename) );

    my $tree = $self->_default_tree();
    $tree->parse_file($filename);

    my $out = $self->format($tree);
    $tree->delete;

    return $out;
}

# ------------------------------------------------------------------------


# ------------------------------------------------------------------------
sub format_from_string { shift->format_string(@_) }

sub format_string {
    my ( $self, $content, @params ) = @_;

    $self = $self->new(@params) unless ref $self;

    croak "What string to format?" unless defined $content;

    my $tree = $self->_default_tree();
    $tree->parse($content);
    $tree->eof();
    undef $content;

    my $out = $self->format($tree);
    $tree->delete;

    return $out;
}

# ------------------------------------------------------------------------
sub _default_tree {
    require HTML::TreeBuilder;
    my $t = HTML::TreeBuilder->new;

    # If nothing else works, try using these parser options:s
    #$t->implicit_body_p_tag(1);
    #$t->p_strict(1);

    return $t;
}

# ------------------------------------------------------------------------


sub format {
    my ( $self, $html ) = @_;

    croak "Usage: \$formatter->format(\$tree)" unless ( defined($html) and ref($html) and $html->can('tag') );

    #### Tree to format: $html->dump

    $self->set_version_tag($html);
    $self->massage_tree($html);
    $self->begin($html);
    $html->number_lists();

    # Per-iteration scratch:
    my ( $node, $start, $depth, $tag, $func );
    $html->traverse(
        sub {
            ( $node, $start, $depth ) = @_;
            if ( ref $node ) {
                $tag = $node->tag;
                $func = $tag . '_' . ( $start ? "start" : "end" );

                # Use ->can so that we can recover if
                # a handler is not defined for the tag.
                if ( $self->can($func) ) {
                    ### Calling : ('  ' x $depth) . $func
                    return $self->$func($node);
                }
                else {
                    ### Skipping: ('  ' x $depth) . $func
                    return 1;
                }
            }
            else {
                $self->textflow($node);
            }
            1;
        }
    );

    $self->end($html);

    return join( '', @{ $self->{output} } );
}

# ------------------------------------------------------------------------
sub begin {
    my $self = shift;

    # Flags
    $self->{anchor}    = 0;
    $self->{underline} = 0;
    $self->{bold}      = 0;
    $self->{italic}    = 0;
    $self->{center}    = 0;

    $self->{superscript}   = 0;
    $self->{subscript}     = 0;
    $self->{strikethrough} = 0;

    $self->{center_stack} = [];    # push and pop 'center' states to it
    $self->{nobr}         = 0;

    $self->{'font_size'} = [3];     # last element is current size
    $self->{basefont_size} = [3];

    $self->{vspace} = undef;        # vertical space (dimension)

    $self->{output} = [];
}

# ------------------------------------------------------------------------
sub end { }

# ------------------------------------------------------------------------
sub set_version_tag {
    my ( $self, $html ) = @_;

    if ($html) {
        $self->{'version_tag'} = sprintf(
            "%s (v%s, using %s v%s%s)",
            ref($self), $self->VERSION || '?',
            ref($html),
            $html->VERSION || '?',
            $HTML::Parser::VERSION ? ", and HTML::Parser v$HTML::Parser::VERSION" : ''
        );
    }
    elsif ($HTML::Parser::VERSION) {
        $self->{'version_tag'} =
            sprintf( "%s (v%s, using %s)", ref($self), $self->VERSION || "?", "HTML::Parser v$HTML::Parser::VERSION", );
    }
    else {
        $self->{'version_tag'} = sprintf( "%s (v%s)", ref($self), $self->VERSION || '?', );
    }
}

# ------------------------------------------------------------------------
sub version_tag { shift->{'version_tag'} }

# ------------------------------------------------------------------------
sub html_start     { 1; }
sub html_end       { }
sub body_start     { 1; }
sub body_end       { }
sub head_start     { 0; }
sub script_start   { 0; }
sub style_start    { 0; }
sub frameset_start { 0; }

# ------------------------------------------------------------------------
sub header_start {
    my ( $self, undef, $node ) = @_;

    my $align = $node->attr('align');
    if ( defined($align) && lc($align) eq 'center' ) {
        $self->{center}++;
    }
    1;
}

# ------------------------------------------------------------------------
sub header_end {
    my ( $self, undef, $node ) = @_;

    my $align = $node->attr('align');
    if ( defined($align) && lc($align) eq 'center' ) {
        $self->{center}--;
    }
}

# ------------------------------------------------------------------------
sub h1_start { shift->header_start( 1, @_ ) }
sub h2_start { shift->header_start( 2, @_ ) }
sub h3_start { shift->header_start( 3, @_ ) }
sub h4_start { shift->header_start( 4, @_ ) }
sub h5_start { shift->header_start( 5, @_ ) }
sub h6_start { shift->header_start( 6, @_ ) }

# ------------------------------------------------------------------------
sub h1_end { shift->header_end( 1, @_ ) }
sub h2_end { shift->header_end( 2, @_ ) }
sub h3_end { shift->header_end( 3, @_ ) }
sub h4_end { shift->header_end( 4, @_ ) }
sub h5_end { shift->header_end( 5, @_ ) }
sub h6_end { shift->header_end( 6, @_ ) }

sub br_start { my $self = shift; $self->vspace( 0, 1 ); }
sub hr_start { my $self = shift; $self->vspace(1); 1; }

# ------------------------------------------------------------------------
sub img_start {
    my ( $self, $node ) = @_;

    my $alt = $node->attr('alt');
    $self->out( defined($alt) ? $alt : "[IMAGE]" );
}

# ------------------------------------------------------------------------
sub a_start      { shift->{anchor}++;    1; }
sub a_end        { shift->{anchor}--; }
sub u_start      { shift->{underline}++; 1; }
sub u_end        { shift->{underline}--; }
sub b_start      { shift->{bold}++;      1; }
sub b_end        { shift->{bold}--; }
sub tt_start     { shift->{teletype}++;  1; }
sub tt_end       { shift->{teletype}--; }
sub i_start      { shift->{italic}++;    1; }
sub i_end        { shift->{italic}--; }
sub center_start { shift->{center}++;    1; }
sub center_end   { shift->{center}--; }

# ------------------------------------------------------------------------
sub div_start {    # interesting only for its 'align' attribute
    my ( $self, $node ) = @_;

    my $align = $node->attr('align');
    if ( defined($align) && lc($align) eq 'center' ) {
        return $self->center_start;
    }
    1;
}

# ------------------------------------------------------------------------
sub div_end {
    my ( $self, $node ) = @_;

    my $align = $node->attr('align');
    if ( defined($align) && lc($align) eq 'center' ) {
        return $self->center_end;
    }
}

# ------------------------------------------------------------------------
sub nobr_start { shift->{nobr}++; 1; }
sub nobr_end   { shift->{nobr}--; }
sub wbr_start  { 1; }

# ------------------------------------------------------------------------
sub font_start {
    my ( $self, $elem ) = @_;

    my $size = $elem->attr('size');
    return 1 unless ( defined($size) );
    if ( $size =~ /^\s*[+\-]/ ) {
        my $base = $self->{basefont_size}[-1];

        # yes, base it on the most recent one
        $size = $base + $size;
    }
    push @{ $self->{'font_size'} }, $size;
    $self->new_font_size($size);
    1;
}

# ------------------------------------------------------------------------
sub font_end {
    my ( $self, $elem ) = @_;
    my $size = $elem->attr('size');
    return unless defined $size;
    pop @{ $self->{'font_size'} };
    $self->restore_font_size( $self->{'font_size'}[-1] );
}

# ------------------------------------------------------------------------
sub big_start {
    my $self = $_[0];
    push @{ $self->{'font_size'} }, $self->{basefont_size}[-1] + 1;    # same as font size="+1"
    $self->new_font_size( $self->{'font_size'}[-1] );
    1;
}

# ------------------------------------------------------------------------
sub small_start {
    my $self = $_[0];
    push @{ $self->{'font_size'} }, $self->{basefont_size}[-1] - 1,    # same as font size="-1"
        ;
    $self->new_font_size( $self->{'font_size'}[-1] );
    1;
}

# ------------------------------------------------------------------------
sub big_end {
    my $self = $_[0];
    pop @{ $self->{'font_size'} };
    $self->restore_font_size( $self->{'font_size'}[-1] );
    1;
}

# ------------------------------------------------------------------------
sub small_end {
    my $self = $_[0];
    pop @{ $self->{'font_size'} };
    $self->restore_font_size( $self->{'font_size'}[-1] );
    1;
}

# ------------------------------------------------------------------------
sub basefont_start {
    my ( $self, $elem ) = @_;
    my $size = $elem->attr('size');
    return unless defined $size;
    push( @{ $self->{basefont_size} }, $size );
    1;
}

# ------------------------------------------------------------------------
sub basefont_end {
    my ( $self, $elem ) = @_;
    my $size = $elem->attr('size');
    return unless defined $size;
    pop( @{ $self->{basefont_size} } );
}

# ------------------------------------------------------------------------
#
# Override in subclasses, if you like.
#
sub new_font_size     { }    #my( $self, $font_size_number ) = @_;
sub restore_font_size { }    #my( $self, $font_size_number ) = @_;

# ------------------------------------------------------------------------
sub q_start      { shift->out(q<">);         1; }
sub q_end        { shift->out(q<">);         1; }
sub sup_start    { shift->{superscript}++;   1; }
sub sup_end      { shift->{superscript}--;   1; }
sub sub_start    { shift->{subscript}++;     1; }
sub sub_end      { shift->{subscript}--;     1; }
sub strike_start { shift->{strikethrough}++; 1; }
sub strike_end   { shift->{strikethrough}--; 1; }
sub s_start      { shift->strike_start(@_); }
sub s_end        { shift->strike_end(@_); }
sub dfn_start    { 1; }
sub dfn_end      { 1; }
sub abbr_start   { 1; }
sub abbr_end     { 1; }
sub acronym_start { 1; }
sub acronym_end   { 1; }
sub span_start    { 1; }
sub span_end      { 1; }
sub ins_start     { 1; }
sub ins_end       { 1; }
sub del_start     { 0; }    # Don't render the del'd bits
sub del_end       { 0; }

# ------------------------------------------------------------------------
my @Size_magic_numbers = (
    0.60, 0.75, 0.89, 1, 1.20, 1.50, 2.00, 3.00

        # #0    #1    #2   #3     #4     #5     #6     #7
        #________________ - | + _________________________
        # -3    -2    -1    0     +1     +2     +3     +4
);

# ------------------------------------------------------------------------
sub scale_font_for {
    my ( $self, $reference_size ) = @_;

    # Mozilla's source, at
    # http://lxr.mozilla.org/seamonkey/source/content/html/style/src/nsStyleUtil.cpp#299
    # says:
    #  static PRInt32 sFontSizeFactors[8] = { 60,75,89,100,120,150,200,300 };
    #
    # For comparison, Gisle's earlier HTML::FormatPS has:
    #    |           # size   0   1   2   3   4   5   6   7
    #    | @FontSizes = ( 5,  6,  8, 10, 12, 14, 18, 24, 32);
    # ...and gets different sizing via just a scaling factor.

    my $size_number = int( defined( $_[2] ) ? $_[2] : $self->{'font_size'}[-1] );

    # force the size_number into range:
    $size_number =
          ( $size_number < 0 )                    ? 0
        : ( $size_number > $#Size_magic_numbers ) ? $#Size_magic_numbers
        :                                           int($size_number);

    my $result = int( .5 + $reference_size * $Size_magic_numbers[$size_number] );

    ### Scale Font: sprintf("reference %s, size %s => %s",  $reference_size, $size_number, $result);

    return $result;
}

# ------------------------------------------------------------------------
# Aliases for logical markup:
sub strong_start { shift->b_start(@_) }
sub strong_end   { shift->b_end(@_) }
sub cite_start   { shift->i_start(@_) }
sub cite_end     { shift->i_end(@_) }
sub em_start     { shift->i_start(@_) }
sub em_end       { shift->i_end(@_) }
sub code_start   { shift->tt_start(@_) }
sub code_end     { shift->tt_end(@_) }
sub kbd_start    { shift->tt_start(@_) }
sub kbd_end      { shift->tt_end(@_) }
sub samp_start   { shift->tt_start(@_) }
sub samp_end     { shift->tt_end(@_) }
sub var_start    { shift->tt_start(@_) }
sub var_end      { shift->tt_end(@_) }

# ------------------------------------------------------------------------
sub p_start {
    my $self = shift;

    #$self->adjust_lm(0); # assert new paragraph
    $self->vspace(1);

    # assert one line's worth of vertical space at para-start
    $self->out('');
    1;
}

# ------------------------------------------------------------------------
sub p_end {
    shift->vspace(1);    # assert one line's worth of vertical space at para-end
}

# ------------------------------------------------------------------------
sub pre_start {
    my $self = shift;

    $self->{pre}++;
    $self->vspace(1);    # assert one line's worth of vertical space at pre-start
    1;
}

# ------------------------------------------------------------------------
sub pre_end {
    my $self = shift;

    $self->{pre}--;      # assert one line's worth of vertical space at pre-end
    $self->vspace(1);
}

# ------------------------------------------------------------------------
sub listing_start { shift->pre_start(@_) }
sub listing_end   { shift->pre_end(@_) }
sub xmp_start     { shift->pre_start(@_) }
sub xmp_end       { shift->pre_end(@_) }

# ------------------------------------------------------------------------
sub blockquote_start {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at blockquote-start
    $self->adjust_lm(+2);
    $self->adjust_rm(-2);
    1;
}

# ------------------------------------------------------------------------
sub blockquote_end {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at blockquote-end
    $self->adjust_lm(-2);
    $self->adjust_rm(+2);
}

# ------------------------------------------------------------------------
sub address_start {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at address-para-start
    $self->i_start(@_);
    1;
}

# ------------------------------------------------------------------------
sub address_end {
    my $self = shift;

    $self->i_end(@_);    # assert one line's worth of vertical space at address-para-end
    $self->vspace(1);
}

# ------------------------------------------------------------------------
# Handling of list elements
sub ul_start {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at ul-start
    $self->adjust_lm(+2);
    1;
}

# ------------------------------------------------------------------------
sub ul_end {
    my $self = shift;

    $self->adjust_lm(-2);    # assert one line's worth of vertical space at ul-end
    $self->vspace(1);
}

# ------------------------------------------------------------------------
sub li_start {
    my $self = shift;

    $self->bullet( shift->attr('_bullet') || '' );
    $self->adjust_lm(+2);
    1;
}

# ------------------------------------------------------------------------
sub bullet { shift->out(@_); }

# ------------------------------------------------------------------------
sub li_end {
    my $self = shift;

    $self->vspace(1);
    $self->adjust_lm(-2);
}

# ------------------------------------------------------------------------
sub menu_start { shift->ul_start(@_) }
sub menu_end   { shift->ul_end(@_) }
sub dir_start  { shift->ul_start(@_) }
sub dir_end    { shift->ul_end(@_) }

# ------------------------------------------------------------------------
sub ol_start {
    my $self = shift;

    $self->vspace(1);
    $self->adjust_lm(+2);
    1;
}

# ------------------------------------------------------------------------
sub ol_end {
    my $self = shift;

    $self->adjust_lm(-2);
    $self->vspace(1);
}

# ------------------------------------------------------------------------
sub dl_start {
    my $self = shift;

    # $self->adjust_lm(+2);
    $self->vspace(1);    # assert one line's worth of vertical space at dl-start
    1;
}

# ------------------------------------------------------------------------
sub dl_end {
    my $self = shift;

    # $self->adjust_lm(-2);
    $self->vspace(1);    # assert one line's worth of vertical space at dl-end
}

# ------------------------------------------------------------------------
sub dt_start {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at dt-start
    1;
}

# ------------------------------------------------------------------------
sub dt_end { }

# ------------------------------------------------------------------------
sub dd_start {
    my $self = shift;

    $self->adjust_lm(+6);
    $self->vspace(0);    # hm, what's that do?  nothing?
    1;
}

# ------------------------------------------------------------------------
sub dd_end {
    my $self = shift;

    $self->vspace(1);    # assert one line's worth of vertical space at dd-end
    $self->adjust_lm(-6);
}

# ------------------------------------------------------------------------

# And now some things that are basically sane fall-throughs for classes
#  that don't really handle tables or forms specially...

# Things not formatted at all
sub input_start    { 0; }
sub textarea_start { 0; }
sub select_start   { 0; }
sub option_start   { 0; }

# ------------------------------------------------------------------------
sub td_start {
    my $self = shift;

    push @{ $self->{'center_stack'} }, $self->{'center'};
    $self->{center} = 0;

    $self->p_start(@_);
}

# ------------------------------------------------------------------------
sub td_end {
    my $self = shift;

    $self->{'center'} = pop @{ $self->{'center_stack'} };
    $self->p_end(@_);
}

# ------------------------------------------------------------------------
sub th_start {
    my $self = shift;

    push @{ $self->{'center_stack'} }, $self->{'center'};
    $self->{center} = 0;

    $self->p_start(@_);
    $self->b_start(@_);
}

# ------------------------------------------------------------------------
sub th_end {
    my $self = shift;

    $self->b_end(@_);
    $self->{'center'} = pop @{ $self->{'center_stack'} };
    $self->p_end(@_);
}

# But if you wanted to just SKIP tables and forms, you'd do this:
#  sub table_start { shift->out('[TABLE NOT SHOWN]'); 0; }
#  sub form_start  { shift->out('[FORM NOT SHOWN]');  0; }

# ------------------------------------------------------------------------
sub textflow {
    my $self = shift;

    if ( $self->{pre} ) {

        # Strip one leading and one trailing newline so that a
        #  tag can be placed on a line of its own without causing extra
        #  vertical space as part of the preformatted text.
        $_[0] =~ s/\n$//;
        $_[0] =~ s/^\n//;
        $self->pre_out( $_[0] );
    }
    else {
        for ( split( /(\s+)/, $_[0] ) ) {
            next unless length $_;
            $self->out($_);
        }
    }
}

# ------------------------------------------------------------------------
sub vspace {
    my ( $self, $min, $add ) = @_;

    # This method sets the vspace attribute.  When vspace is
    # defined, then a new line should be started.  If vspace
    # is a nonzero value, then that should be taken as the
    # number of lines to be skipped before following text
    # is written out.
    #
    # You may think it odd to conflate the two concepts of
    # ending this paragraph, and asserting how much space should
    # follow; but it happens to work out pretty well.

    my $old = $self->{vspace};
    if ( defined $old ) {
        my $new = $old;
        $new += $add || 0;
        $new = $min if $new < $min;
        $self->{vspace} = $new;
    }
    else {
        $self->{vspace} = $min;
    }
    ### vspace: $self->{vspace}
    $old;
}

# ------------------------------------------------------------------------
sub collect { push( @{ shift->{output} }, @_ ); }

# ------------------------------------------------------------------------
sub out       { confess "Must be overridden by subclass"; }    # Output a word
sub pre_out   { confess "Must be overridden by subclass"; }
sub adjust_lm { confess "Must be overridden by subclass"; }
sub adjust_rm { confess "Must be overridden by subclass"; }

# ------------------------------------------------------------------------


1;

__END__