Raw content of Bio::DB::GFF::RelSegment
<![CDATA[=head1 NAME
Bio::DB::GFF::RelSegment -- Sequence segment with relative coordinate support
=head1 SYNOPSIS
See L<Bio::DB::GFF>.
=head1 DESCRIPTION
Bio::DB::GFF::RelSegment is a stretch of sequence that can handle
relative coordinate addressing. It inherits from
Bio::DB::GFF::Segment, and is the base class for
Bio::DB::GFF::Feature.
In addition to the source sequence, a relative segment has a
"reference sequence", which is used as the basis for its coordinate
system. The reference sequence can be changed at will, allowing you
freedom to change the "frame of reference" for features contained
within the segment. For example, by setting a segment's reference
sequence to the beginning of a gene, you can view all other features
in gene-relative coordinates.
The reference sequence and the source sequence must be on the same
physical stretch of DNA, naturally. However, they do not have to be
on the same strand. The strandedness of the reference sequence
determines whether coordinates increase to the right or the left.
Generally, you will not create or manipulate Bio::DB::GFF::RelSeg0ment
objects directly, but use those that are returned by the Bio::DB::GFF
module.
=head2 An Example
To understand how relative coordinates work, consider the following
example from the C. elegans database. First we create the appropriate
GFF accessor object (the factory):
my $db = Bio::DB::GFF->new(-dsn => 'dbi:mysql:elegans',
-adaptor=>'dbi:mysqlopt');
Now we fetch out a segment based on cosmid clone ZK909:
my $seg = $db->segment('ZK909');
If we call the segment's refseq() method, we see that the base of the
coordinate system is the sequence "ZK154", and that its start and
stop positions are 1 and the length of the cosmid:
print $seg->refseq;
=> ZK909
print $seg->start,' - ',$seg->stop;
=> 1 - 33782
As a convenience, the "" operator is overloaded in this class, to give
the reference sequence, and start and stop positions:
print $seg;
=> ZK909:1,33782
Internally, Bio::DB::GFF::RelSegment has looked up the absolute
coordinates of this segment and maintains the source sequence and the
absolute coordinates relative to the source sequence. We can see this
information using sourceseq() (inherited from Bio::DB::GFF::Segment)
and the abs_start() and abs_end() methods:
print $seg->sourceseq;
=> CHROMOSOME_I
print $seg->abs_start,' - ',$seg->abs_end;
=> 14839545 - 14873326
We can also put the segment into absolute mode, so that it behaves
like Bio::DB::Segment, and always represents coordinates on the source
sequence. This is done by passing a true value to the absolute()
method:
$seq->absolute(1);
print $seg;
=> CHROMOSOME_I:14839545,14873326
We can change the reference sequence at any time. One way is to call
the segment's ref() method, giving it the ID (and optionally the
class) of another landmark on the genome. For example, if we know
that cosmid ZK337 is adjacent to ZK909, then we can view ZK909 in
ZK337-relative coordinates:
$seg->refseq('ZK337');
print $seg;
=> ZK337:-33670,111
We can call the segment's features() method in order to get the list
of contigs that overlap this segment (in the C. elegans database,
contigs have feature type "Sequence:Link"):
@links = $seg->features('Sequence:Link');
We can now set the reference sequence to the first of these contigs like so:
$seg->refseq($links[0]);
print $seg;
=> Sequence:Link(LINK_Y95D11A):3997326,4031107
=cut
package Bio::DB::GFF::RelSegment;
use strict;
use Bio::DB::GFF::Feature;
use Bio::DB::GFF::Util::Rearrange;
use Bio::DB::GFF::Segment;
use Bio::RangeI;
use vars qw(@ISA);
@ISA = qw(Bio::DB::GFF::Segment);
use overload '""' => 'asString',
'bool' => sub { overload::StrVal(shift) },
fallback=>1;
=head1 API
The remainder of this document describes the API for
Bio::DB::GFF::Segment.
=cut
=head2 new
Title : new
Usage : $s = Bio::DB::GFF::RelSegment->new(@args)
Function: create a new relative segment
Returns : a new Bio::DB::GFF::RelSegment object
Args : see below
Status : Public
This method creates a new Bio::DB::GFF::RelSegment object. Generally
this is called automatically by the Bio::DB::GFF module and
derivatives.
This function uses a named-argument style:
-factory a Bio::DB::GFF::Adaptor to use for database access
-seq ID of the source sequence
-class class of the source sequence
-start start of the desired segment relative to source sequence
-stop stop of the desired segment relative to source sequence
-ref ID of the reference sequence
-refclass class of the reference sequence
-offset 0-based offset from source sequence to start of segment
-length length of desired segment
-absolute, -force_absolute
use absolute coordinates, rather than coordinates relative
to the start of self or the reference sequence
The -seq argument accepts the ID of any landmark in the database. The
stored source sequence becomes whatever the GFF file indicates is the
proper sequence for this landmark. A class of "Sequence" is assumed
unless otherwise specified in the -class argument.
If the argument to -seq is a Bio::GFF::Featname object (such as
returned by the group() method), then the class is taken from that.
The optional -start and -stop arguments specify the end points for the
retrieved segment. For those who do not like 1-based indexing,
-offset and -length are provided. If both -start/-stop and
-offset/-length are provided, the latter overrides the former.
Generally it is not a good idea to mix metaphors.
-ref and -refclass together indicate a sequence to be used for
relative coordinates. If not provided, the source sequence indicated
by -seq is used as the reference sequence. If the argument to -ref is
a Bio::GFF::Featname object (such as returned by the group() method),
then the class is taken from that.
-force_absolute should be used if you wish to skip the lookup of the
absolute position of the source sequence that ordinarily occurs when
you create a relative segment. In this case, the source sequence must
be a sequence that has been specified as the "source" in the GFF file.
=cut
# Create a new Bio::DB::GFF::RelSegment Object
# arguments are:
# -factory => factory and DBI interface
# -seq => $sequence_name
# -start => $start_relative_to_sequence
# -stop => $stop_relative_to_sequence
# -ref => $sequence which establishes coordinate system
# -offset => 0-based offset relative to sequence
# -length => length of segment
# -nocheck => turn off checking, force segment to be constructed
# -absolute => use absolute coordinate addressing
#'
sub new {
my $package = shift;
my ($factory,$name,$start,$stop,$refseq,$class,$refclass,$offset,$length,$force_absolute,$nocheck) =
rearrange([
'FACTORY',
[qw(NAME SEQ SEQUENCE SOURCESEQ)],
[qw(START BEGIN)],
[qw(STOP END)],
[qw(REFSEQ REF REFNAME)],
[qw(CLASS SEQCLASS)],
qw(REFCLASS),
[qw(OFFSET OFF)],
[qw(LENGTH LEN)],
[qw(ABSOLUTE)],
[qw(NOCHECK FORCE)],
],@_);
$package = ref $package if ref $package;
$factory or $package->throw("new(): provide a -factory argument");
# to allow people to use segments as sources
if (ref($name) && $name->isa('Bio::DB::GFF::Segment')) {
$start = 1 unless defined $start;
$stop = $name->length unless defined $stop;
return $name->subseq($start,$stop);
}
my @object_results;
# support for Featname objects
if (ref($name) && $name->can('class')) {
$class = $name->class;
$name = $name->name;
}
# if the class of the landmark is not specified then default to 'Sequence'
$class ||= eval{$factory->default_class} || 'Sequence';
# confirm that indicated sequence is actually in the database!
my @abscoords;
# abscoords() will now return an array ref, each element of which is
# ($absref,$absclass,$absstart,$absstop,$absstrand)
if ($nocheck) {
$force_absolute++;
$start = 1;
}
if ($force_absolute && defined($start)) { # absolute position is given to us
@abscoords = ([$name,$class,$start,$stop,'+']);
} else {
my $result = $factory->abscoords($name,$class,$force_absolute ? $name : ()) or return;
@abscoords = @$result;
}
foreach (@abscoords) {
my ($absref,$absclass,$absstart,$absstop,$absstrand,$sname) = @$_;
$sname = $name unless defined $sname;
my ($this_start,$this_stop,$this_length) = ($start,$stop,$length);
# partially fill in object
my $self = bless { factory => $factory },$package;
$absstrand ||= '+';
# an explicit length overrides start and stop
if (defined $offset) {
warn "new(): bad idea to call new() with both a start and an offset"
if defined $this_start;
$this_start = $offset+1;
}
if (defined $this_length) {
warn "new(): bad idea to call new() with both a stop and a length"
if defined $this_stop;
$this_stop = $this_start + $length - 1;
}
# this allows a SQL optimization way down deep
$self->{whole}++ if $absref eq $sname and !defined($this_start) and !defined($this_stop);
$this_start = 1 if !defined $this_start;
$this_stop = $absstop-$absstart+1 if !defined $this_stop;
$this_length = $this_stop - $this_start + 1;
# now offset to correct subsegment based on desired start and stop
if ($force_absolute) {
($this_start,$this_stop) = ($absstart,$absstop);
$self->absolute(1);
} elsif ($absstrand eq '+') {
$this_start = $absstart + $this_start - 1;
$this_stop = $this_start + $this_length - 1;
} else {
$this_start = $absstop - ($this_start - 1);
$this_stop = $absstop - ($this_stop - 1);
}
# handle truncation in either direction
# This only happens if the segment runs off the end of
# the reference sequence
if ($factory->strict_bounds_checking &&
(($this_start < $absstart) || ($this_stop > $absstop))) {
# return empty if we are completely off the end of the ref se
next unless $this_start<=$absstop && $this_stop>=$absstart;
if (my $a = $factory->abscoords($absref,'Sequence')) {
my $refstart = $a->[0][2];
my $refstop = $a->[0][3];
if ($this_start < $refstart) {
$this_start = $refstart;
$self->{truncated}{start}++;
}
if ($this_stop > $refstop) {
$this_stop = $absstop;
$self->{truncated}{stop}++;
}
}
}
@{$self}{qw(sourceseq start stop strand class)}
= ($absref,$this_start,$this_stop,$absstrand,$absclass);
# handle reference sequence
if (defined $refseq) {
$refclass = $refseq->class if $refseq->can('class');
$refclass ||= 'Sequence';
my ($refref,$refstart,$refstop,$refstrand) = $factory->abscoords($refseq,$refclass);
unless ($refref eq $absref) {
$self->error("reference sequence is on $refref but source sequence is on $absref");
return;
}
$refstart = $refstop if $refstrand eq '-';
@{$self}{qw(ref refstart refstrand)} = ($refseq,$refstart,$refstrand);
} else {
$absstart = $absstop if $absstrand eq '-';
@{$self}{qw(ref refstart refstrand)} = ($sname,$absstart,$absstrand);
}
push @object_results,$self;
}
return wantarray ? @object_results : $object_results[0];
}
# overridden methods
# start, stop, length
sub start {
my $self = shift;
return $self->strand < 0 ? $self->{stop} : $self->{start} if $self->absolute;
$self->_abs2rel($self->{start});
}
sub end {
my $self = shift;
return $self->strand < 0 ? $self->{start} : $self->{stop} if $self->absolute;
$self->_abs2rel($self->{stop});
}
*stop = \&end;
sub length {
my $self = shift;
return unless defined $self->abs_end;
abs($self->abs_end - $self->abs_start) + 1;
}
sub abs_start {
my $self = shift;
if ($self->absolute) {
my ($a,$b) = ($self->SUPER::abs_start,$self->SUPER::abs_end);
return ($a<$b) ? $a : $b;
}
else {
return $self->SUPER::abs_start(@_);
}
}
sub abs_end {
my $self = shift;
if ($self->absolute) {
my ($a,$b) = ($self->SUPER::abs_start,$self->SUPER::abs_end);
return ($a>$b) ? $a : $b;
}
else {
return $self->SUPER::abs_end(@_);
}
}
=head2 refseq
Title : refseq
Usage : $ref = $s->refseq([$newseq] [,$newseqclass])
Function: get/set reference sequence
Returns : current reference sequence
Args : new reference sequence and class (optional)
Status : Public
This method will get or set the reference sequence. Called with no
arguments, it returns the current reference sequence. Called with
either a sequence ID and class, a Bio::DB::GFF::Segment object (or
subclass) or a Bio::DB::GFF::Featname object, it will set the current
reference sequence and return the previous one.
The method will generate an exception if you attempt to set the
reference sequence to a sequence that isn't contained in the database,
or one that has a different source sequence from the segment.
=cut
#'
sub refseq {
my $self = shift;
my $g = $self->{ref};
if (@_) {
my ($newref,$newclass);
if (@_ == 2) {
$newclass = shift;
$newref = shift;
} else {
$newref = shift;
$newclass = 'Sequence';
}
defined $newref or $self->throw('refseq() called with an undef reference sequence');
# support for Featname objects
$newclass = $newref->class if ref($newref) && $newref->can('class');
# $self->throw("Cannot define a segment's reference sequence in terms of itself!")
# if ref($newref) and overload::StrVal($newref) eq overload::StrVal($self);
my ($refsource,undef,$refstart,$refstop,$refstrand);
if ($newref->isa('Bio::DB::GFF::RelSegment')) {
($refsource,undef,$refstart,$refstop,$refstrand) =
($newref->sourceseq,undef,$newref->abs_start,$newref->abs_end,$newref->abs_strand >= 0 ? '+' : '-');
} else {
my $coords = $self->factory->abscoords($newref,$newclass);
foreach (@$coords) { # find the appropriate one
($refsource,undef,$refstart,$refstop,$refstrand) = @$_;
last if $refsource eq $self->{sourceseq};
}
}
$self->throw("can't set reference sequence: $newref and $self are on different sequence segments")
unless $refsource eq $self->{sourceseq};
@{$self}{qw(ref refstart refstrand)} = ($newref,$refstart,$refstrand);
$self->absolute(0);
}
return $self->absolute ? $self->sourceseq : $g;
}
=head2 abs_low
Title : abs_low
Usage : $s->abs_low
Function: the absolute lowest coordinate of the segment
Returns : an integer
Args : none
Status : Public
This is for GadFly compatibility, and returns the low coordinate in
absolute coordinates;
=cut
sub abs_low {
my $self = shift;
my ($a,$b) = ($self->abs_start,$self->abs_end);
return ($a<$b) ? $a : $b;
}
=head2 abs_high
Title : abs_high
Usage : $s->abs_high
Function: the absolute highest coordinate of the segment
Returns : an integer
Args : none
Status : Public
This is for GadFly compatibility, and returns the high coordinate in
absolute coordinates;
=cut
sub abs_high {
my $self = shift;
my ($a,$b) = ($self->abs_start,$self->abs_end);
return ($a>$b) ? $a : $b;
}
=head2 asString
Title : asString
Usage : $s->asString
Function: human-readable representation of the segment
Returns : a string
Args : none
Status : Public
This method will return a human-readable representation of the
segment. It is the overloaded method call for the "" operator.
Currently the format is:
refseq:start,stop
=cut
sub asString {
my $self = shift;
return $self->SUPER::asString if $self->absolute;
my $label = $self->{ref};
my $start = $self->start || '';
my $stop = $self->stop || '';
if (ref($label) && overload::StrVal($self) eq overload::StrVal($label->ref)) {
$label = $self->abs_ref;
$start = $self->abs_start;
$stop = $self->abs_end;
}
return "$label:$start,$stop";
}
sub name { shift->asString }
=head2 absolute
Title : absolute
Usage : $abs = $s->absolute([$abs])
Function: get/set absolute coordinates
Returns : a boolean flag
Args : new setting for flag (optional)
Status : Public
Called with a boolean flag, this method controls whether to display
relative coordinates (relative to the reference sequence) or absolute
coordinates (relative to the source sequence). It will return the
previous value of the setting.
=cut
sub absolute {
my $self = shift;
my $g = $self->{absolute};
$self->{absolute} = shift if @_;
$g;
}
=head2 features
Title : features
Usage : @features = $s->features(@args)
Function: get features that overlap this segment
Returns : a list of Bio::DB::GFF::Feature objects
Args : see below
Status : Public
This method will find all features that overlap the segment and return
a list of Bio::DB::GFF::Feature objects. The features will use
coordinates relative to the reference sequence in effect at the time
that features() was called.
The returned list can be limited to certain types of feature by
filtering on their method and/or source. In addition, it is possible
to obtain an iterator that will step through a large number of
features sequentially.
Arguments can be provided positionally or using the named arguments
format. In the former case, the arguments are a list of feature types
in the format "method:source". Either method or source can be
omitted, in which case the missing component is treated as a wildcard.
If no colon is present, then the type is treated as a method name.
Multiple arguments are ORed together.
Examples:
@f = $s->features('exon:curated'); # all curated exons
@f = $s->features('exon:curated','intron'); # curated exons and all introns
@f = $s->features('similarity:.*EST.*'); # all similarities
# having something to do
# with ESTs
The named parameter form gives you control over a few options:
-types an array reference to type names in the format
"method:source"
-merge Whether to apply aggregators to the generated features (default yes)
-rare Turn on an optimization suitable for a relatively rare feature type,
where it will be faster to filter by feature type first
and then by position, rather than vice versa.
-attributes a hashref containing a set of attributes to match
-iterator Whether to return an iterator across the features.
-binsize A true value will create a set of artificial features whose
start and stop positions indicate bins of the given size, and
whose scores are the number of features in the bin. The
class and method of the feature will be set to "bin",
its source to "method:source", and its group to "bin:method:source".
This is a handy way of generating histograms of feature density.
-merge is a boolean flag that controls whether the adaptor's
aggregators wll be applied to the features returned by this method.
If -iterator is true, then the method returns a single scalar value
consisting of a Bio::SeqIO object. You can call next_seq() repeatedly
on this object to fetch each of the features in turn. If iterator is
false or absent, then all the features are returned as a list.
The -attributes argument is a hashref containing one or more
attributes to match against:
-attributes => { Gene => 'abc-1',
Note => 'confirmed' }
Attribute matching is simple string matching, and multiple attributes
are ANDed together.
=cut
#'
# return all features that overlap with this segment;
# optionally modified by a list of types to filter on
sub features {
my $self = shift;
my @args = $self->_process_feature_args(@_);
return $self->factory->overlapping_features(@args);
}
=head2 top_SeqFeatures
Title : top_SeqFeatures
Usage :
Function:
Example :
Returns :
Args :
Alias for features(). Provided for Bio::SeqI compatibility.
=cut
=head2 all_SeqFeatures
Title : all_SeqFeatures
Usage :
Function:
Example :
Returns :
Args :
Alias for features(). Provided for Bio::SeqI compatibility.
=cut
=head2 sub_SeqFeatures
Title : sub_SeqFeatures
Usage :
Function:
Example :
Returns :
Args :
Alias for features(). Provided for Bio::SeqI compatibility.
=cut
*top_SeqFeatures = *all_SeqFeatures = \&features;
=head2 get_feature_stream
Title : features
Usage : $stream = $s->get_feature_stream(@args)
Function: get a stream of features that overlap this segment
Returns : a Bio::SeqIO::Stream-compliant stream
Args : see below
Status : Public
This is the same as features(), but returns a stream. Use like this:
$stream = $s->get_feature_stream('exon');
while (my $exon = $stream->next_seq) {
print $exon->start,"\n";
}
=cut
sub get_feature_stream {
my $self = shift;
my @args = $_[0] =~ /^-/ ? (@_,-iterator=>1) : (-types=>\@_,-iterator=>1);
$self->features(@args);
}
=head2 get_seq_stream
Title : get_seq_stream
Usage : $stream = $s->get_seq_stream(@args)
Function: get a stream of features that overlap this segment
Returns : a Bio::SeqIO::Stream-compliant stream
Args : see below
Status : Public
This is the same as feature_stream(), and is provided for Bioperl
compatibility. Use like this:
$stream = $s->get_seq_stream('exon');
while (my $exon = $stream->next_seq) {
print $exon->start,"\n";
}
=cut
*get_seq_stream = \&get_feature_stream;
=head2 overlapping_features
Title : overlapping_features
Usage : @features = $s->overlapping_features(@args)
Function: get features that overlap this segment
Returns : a list of Bio::DB::GFF::Feature objects
Args : see features()
Status : Public
This is an alias for the features() method, and takes the same
arguments.
=cut
*overlapping_features = \&features;
=head2 contained_features
Title : contained_features
Usage : @features = $s->contained_features(@args)
Function: get features that are contained by this segment
Returns : a list of Bio::DB::GFF::Feature objects
Args : see features()
Status : Public
This is identical in behavior to features() except that it returns
only those features that are completely contained within the segment,
rather than any that overlap.
=cut
# return all features completely contained within this segment
sub contained_features {
my $self = shift;
local $self->{whole} = 0;
my @args = $self->_process_feature_args(@_);
return $self->factory->contained_features(@args);
}
# *contains = \&contained_features;
=head2 contained_in
Title : contained_in
Usage : @features = $s->contained_in(@args)
Function: get features that contain this segment
Returns : a list of Bio::DB::GFF::Feature objects
Args : see features()
Status : Public
This is identical in behavior to features() except that it returns
only those features that completely contain the segment.
=cut
# return all features completely contained within this segment
sub contained_in {
my $self = shift;
local $self->{whole} = 0;
my @args = $self->_process_feature_args(@_);
return $self->factory->contained_in(@args);
}
=head2 _process_feature_args
Title : _process_feature_args
Usage : @args = $s->_process_feature_args(@args)
Function: preprocess arguments passed to features,
contained_features, and overlapping_features
Returns : a list of parsed arguents
Args : see feature()
Status : Internal
This is an internal method that is used to check and format the
arguments to features() before passing them on to the adaptor.
=cut
sub _process_feature_args {
my $self = shift;
my ($ref,$class,$start,$stop,$strand,$whole)
= @{$self}{qw(sourceseq class start stop strand whole)};
($start,$stop) = ($stop,$start) if $strand eq '-';
my @args = (-ref=>$ref,-class=>$class);
# indicating that we are fetching the whole segment allows certain
# SQL optimizations.
push @args,(-start=>$start,-stop=>$stop) unless $whole;
if (@_) {
if ($_[0] =~ /^-/) {
push @args,@_;
} else {
my @types = @_;
push @args,-types=>\@types;
}
}
push @args,-parent=>$self;
@args;
}
=head2 types
Title : types
Usage : @types = $s->types([-enumerate=>1])
Function: list feature types that overlap this segment
Returns : a list of Bio::DB::GFF::Typename objects or a hash
Args : see below
Status : Public
The types() method will return a list of Bio::DB::GFF::Typename
objects, each corresponding to a feature that overlaps the segment.
If the optional -enumerate parameter is set to a true value, then the
method will return a hash in which the keys are the type names and the
values are the number of times a feature of that type is present on
the segment. For example:
%count = $s->types(-enumerate=>1);
=cut
# wrapper for lower-level types() call.
sub types {
my $self = shift;
my ($ref,$class,$start,$stop,$strand) = @{$self}{qw(sourceseq class start stop strand)};
($start,$stop) = ($stop,$start) if $strand eq '-';
my @args;
if (@_ && $_[0] !~ /^-/) {
@args = (-type => \@_)
} else {
@args = @_;
}
$self->factory->types(-ref => $ref,
-class => $class,
-start=> $start,
-stop => $stop,
@args);
}
=head1 Internal Methods
The following are internal methods and should not be called directly.
=head2 new_from_segment
Title : new_from_segment
Usage : $s = $segment->new_from_segment(@args)
Function: create a new relative segment
Returns : a new Bio::DB::GFF::RelSegment object
Args : see below
Status : Internal
This constructor is used internally by the subseq() method. It forces
the new segment into the Bio::DB::GFF::RelSegment package, regardless
of the package that it is called from. This causes subclass-specfic
information, such as feature types, to be dropped when a subsequence
is created.
=cut
sub new_from_segment {
my $package = shift;
$package = ref $package if ref $package;
my $segment = shift;
my $new = {};
@{$new}{qw(factory sourceseq start stop strand class ref refstart refstrand)}
= @{$segment}{qw(factory sourceseq start stop strand class ref refstart refstrand)};
return bless $new,__PACKAGE__;
}
=head2 _abs2rel
Title : _abs2rel
Usage : @coords = $s->_abs2rel(@coords)
Function: convert absolute coordinates into relative coordinates
Returns : a list of relative coordinates
Args : a list of absolute coordinates
Status : Internal
This is used internally to map from absolute to relative
coordinates. It does not take the offset of the reference sequence
into account, so please use abs2rel() instead.
=cut
sub _abs2rel {
my $self = shift;
my @result;
return unless defined $_[0];
if ($self->absolute) {
@result = @_;
} else {
my ($refstart,$refstrand) = @{$self}{qw(refstart refstrand)};
@result = defined($refstrand) && $refstrand eq '-' ? map { $refstart - $_ + 1 } @_
: map { $_ - $refstart + 1 } @_;
}
# if called with a single argument, caller will expect a single scalar reply
# not the size of the returned array!
return $result[0] if @result == 1 and !wantarray;
@result;
}
=head2 rel2abs
Title : rel2abs
Usage : @coords = $s->rel2abs(@coords)
Function: convert relative coordinates into absolute coordinates
Returns : a list of absolute coordinates
Args : a list of relative coordinates
Status : Public
This function takes a list of positions in relative coordinates to the
segment, and converts them into absolute coordinates.
=cut
sub rel2abs {
my $self = shift;
my @result;
if ($self->absolute) {
@result = @_;
} else {
my ($abs_start,$abs_strand) = ($self->abs_start,$self->abs_strand);
@result = $abs_strand < 0 ? map { $abs_start - $_ + 1 } @_
: map { $_ + $abs_start - 1 } @_;
}
# if called with a single argument, caller will expect a single scalar reply
# not the size of the returned array!
return $result[0] if @result == 1 and !wantarray;
@result;
}
=head2 abs2rel
Title : abs2rel
Usage : @rel_coords = $s-abs2rel(@abs_coords)
Function: convert absolute coordinates into relative coordinates
Returns : a list of relative coordinates
Args : a list of absolutee coordinates
Status : Public
This function takes a list of positions in absolute coordinates
and returns a list expressed in relative coordinates.
=cut
sub abs2rel {
my $self = shift;
my @result;
if ($self->absolute) {
@result = @_;
} else {
my ($abs_start,$abs_strand) = ($self->abs_start,$self->abs_strand);
@result = $abs_strand < 0 ? map { $abs_start - $_ + 1 } @_
: map { $_ - $abs_start + 1 } @_;
}
# if called with a single argument, caller will expect a single scalar reply
# not the size of the returned array!
return $result[0] if @result == 1 and !wantarray;
@result;
}
sub subseq {
my $self = shift;
my $obj = $self->SUPER::subseq(@_);
bless $obj,__PACKAGE__; # always bless into the generic RelSegment package
}
sub strand {
my $self = shift;
if ($self->absolute) {
return _to_strand($self->{strand});
}
return $self->stop <=> $self->start;
}
sub _to_strand {
my $s = shift;
return -1 if $s eq '-';
return +1 if $s eq '+';
return 0;
}
=head2 Bio::RangeI Methods
The following Bio::RangeI methods are supported:
overlaps(), contains(), equals(),intersection(),union(),overlap_extent()
=cut
sub intersection {
my $self = shift;
my (@ranges) = @_;
unshift @ranges,$self if ref $self;
$ranges[0]->isa('Bio::DB::GFF::RelSegment')
or return $self->SUPER::intersection(@_);
my $ref = $ranges[0]->abs_ref;
my ($low,$high);
foreach (@ranges) {
return unless $_->can('abs_ref');
$ref eq $_->abs_ref or return;
$low = $_->abs_low if !defined($low) or $low < $_->abs_low;
$high = $_->abs_high if !defined($high) or $high > $_->abs_high;
}
return unless $low < $high;
$self->new(-factory=> $self->factory,
-seq => $ref,
-start => $low,
-stop => $high);
}
sub overlaps {
my $self = shift;
my($other,$so) = @_;
return $self->SUPER::overlaps(@_) unless $other->isa('Bio::DB::GFF::RelSegment');
return if $self->abs_ref ne $other->abs_ref;
return if $self->abs_low > $other->abs_high;
return if $self->abs_high < $other->abs_low;
1;
}
sub contains {
my $self = shift;
my($other,$so) = @_;
return $self->SUPER::overlaps(@_) unless $other->isa('Bio::DB::GFF::RelSegment');
return if $self->abs_ref ne $other->abs_ref;
return unless $self->abs_low <= $other->abs_low;
return unless $self->abs_high >= $other->abs_high;
1;
}
sub union {
my $self = shift;
my (@ranges) = @_;
unshift @ranges,$self if ref $self;
$ranges[0]->isa('Bio::DB::GFF::RelSegment')
or return $self->SUPER::union(@_);
my $ref = $ranges[0]->abs_ref;
my ($low,$high);
foreach (@ranges) {
return unless $_->can('abs_ref');
$ref eq $_->abs_ref or return;
$low = $_->abs_low if !defined($low) or $low > $_->abs_low;
$high = $_->abs_high if !defined($high) or $high < $_->abs_high;
}
$self->new(-factory=> $self->factory,
-seq => $ref,
-start => $low,
-stop => $high);
}
1;
__END__
=head1 BUGS
Schemas need some work.
=head1 SEE ALSO
L<bioperl>
=head1 AUTHOR
Lincoln Stein E<lt>lstein@cshl.orgE<gt>.
Copyright (c) 2001 Cold Spring Harbor Laboratory.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
]]>