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lib/CSS/Janus.pm  view on Meta::CPAN

sub fixBackgroundPosition {
    my $self = shift;
    my $line = shift;

    $line =~ s{$BG_HORIZONTAL_PERCENTAGE_RE}{
	calculateNewBackgroundPosition($&, $1, $2, $3, $4, $5)
    }eg;
    $line =~ s{$BG_HORIZONTAL_PERCENTAGE_X_RE}{
	calculateNewBackgroundPositionX($&, $1, $2)
    }eg;
    $line =~ s{$BG_HORIZONTAL_LENGTH_RE}{
	$self->calculateNewBackgroundLengthPosition($&, $1, $2, $3, $4, $5)
    }eg;
    $line =~ s{$BG_HORIZONTAL_LENGTH_X_RE}{
	$self->calculateNewBackgroundLengthPositionX($&, $1, $2)
    }eg;

    return $line;
}

# Takes a list of zero to four border radius parts and returns a string of
# them reordered for bidi mirroring.

sub reorderBorderRadiusPart {
    my @part = @_;

    # Remove any piece which may be 'None'
    @part = grep { defined $_ and length $_ } @part;

    if (scalar @part == 4) {
	return "$part[1] $part[0] $part[3] $part[2]";
    } elsif (scalar @part == 3) {
	return "$part[1] $part[0] $part[1] $part[2]";
    } elsif (scalar @part == 2) {
	return "$part[1] $part[0]";
    } elsif (scalar @part == 1) {
	return $part[0];
    } elsif (scalar @part == 0) {
	return '';
    } else {
	croak "This can't happen!";
    }
}

# Receives a match object for a border-radius element and reorders it pieces.
sub reorderBorderRadius {
    my @m = @_;

    my $first_group  = reorderBorderRadiusPart(@m[3 .. 6]);
    my $second_group = reorderBorderRadiusPart(@m[7 .. $#m]);
    if ($second_group eq '') {
	return sprintf '%sborder-radius%s%s', $_[1], $_[2], $first_group;
    } else {
	return sprintf '%sborder-radius%s%s / %s', $_[1], $_[2],
	    $first_group, $second_group;
    }
}

# calculateNewBackgroundPosition ($&, $1, $2, $3, $4, $5)
#
# Changes horizontal background-position percentages, e.g.:
# 'background-position: 75% 50%' => 'background-position: 25% 50%'

sub calculateNewBackgroundPosition {
    my @m = @_;
    my $new_x;
    my $position_string;

    # The flipped value is the offset from 100%
    $new_x = 100 - int($m[4]);

    # Since m.group(1) may very well be None type and we need a string..
    if ($m[1]) {
	$position_string = $m[1];
    } else {
	$position_string = '';
    }

    return sprintf 'background%s%s%s%s%%%s',
	$position_string, $m[2], $m[3], $new_x, $m[5];
}

# calculateNewBackgroundPositionX ($&, $1, $2)
#
# Fixes percent based background-position-x, e.g.:
# 'background-position-x: 75%' => 'background-position-x: 25%'

sub calculateNewBackgroundPositionX {
    my @m = @_;
    my $new_x;

    # The flipped value is the offset from 100%
    $new_x = 100 - int($m[2]);

    return sprintf 'background-position-x%s%s%%', $m[1], $new_x;
}

my $BACKGROUND_POSITION_ERROR_MESSAGE =
    "Unmirrorable horizonal value \"%s\": %s\n";

sub warnForBackgroundPosition {
    my $self        = shift;
    my $bad_length  = shift;
    my $whole_value = shift;

    my $msg = sprintf $BACKGROUND_POSITION_ERROR_MESSAGE, $bad_length,
	$whole_value;
    if ($self->{'ignore_bad_bgp'}) {
	$@ = $msg;
	carp $msg;
    } else {
	croak $msg;
    }
}

# calculateNewBackgroundLengthPosition ($&, $1, $2, $3, $4, $5)
#
# Changes horizontal background-position lengths, e.g.:
# 'background-position: 0px 10px' => 'background-position: 100% 10px'
#
# If value is not replaceable, croak it (by default) or carp it (if
# 'ignore_bad_bgp' option is set).

sub calculateNewBackgroundLengthPosition {
    my $self = shift;
    my @m    = @_;
    my $position_string;

    # croak if the length is not zero-valued
    unless ($m[4] =~ m{^$ZERO_LENGTH}) {
	$self->warnForBackgroundPosition($m[4], $m[0]);
	return $m[0];
    }

    if (defined $m[1] and length $m[1]) {
	$position_string = $m[1];
    } else {
	$position_string = '';
    }

    return sprintf 'background%s%s%s100%%%s',
	$position_string, $m[2], $m[3], $m[5];
}

# calculateNewBackgroundLengthPositionX ($&, $1, $2)