NAME¶
Text::Bidi::Paragraph - Run the bidi algorithm on one paragraph
VERSION¶
version 2.09
SYNOPSIS¶
use Text::Bidi::Paragraph;
my $par = new Text::Bidi::Paragraph $logical;
my $offset = 0;
my $width = 80;
while ( $offset < $p->len ) {
my $v = $p->visual($offset, $width);
say $v;
$offset += $width;
}
DESCRIPTION¶
This class provides the main interface for applying the bidi algorithm in full
generality. In the case where the paragraph can be formatted at once,
"log2vis" in Text::Bidi can be used as a shortcut.
A paragraph is processed by creating a Text::Bidi::Paragraph object:
$par = new Text::Bidi::Paragraph $logical;
Here $logical is the text of the paragraph. This applies the first stages of the
bidi algorithm: computation of the embedding levels. Once this is done, the
text can be displayed using the "visual" method, which does the
reordering.
METHODS¶
new¶
my $par = new Text::Bidi::Paragraph $logical, ...;
Create a new object corresponding to a text
$logical in
logical order. The other arguments are key-value pairs. The only ones that
have a meaning at the moment are
bd, which supplies the Text::Bidi
object to use, and
dir, which prescribes the direction of the
paragraph. The value of
dir is a constant in
"Text::Bidi::Par::" (e.g., $Text::Bidi::Par::RTL; see
Text::Bidi::Constants).
Note that the mere creation of
$par runs the bidi algorithm
on the given text
$logical up to the point of reordering
(which is dealt with in "visual").
par¶
my $logical = $par->par;
Returns the logical (input) text corresponding to this paragraph.
dir¶
my $dir = $par->dir;
Returns the direction of this paragraph, a constant in the $Text::Bidi::Par::
namespace.
len¶
my $len = $par->len;
The length of this paragraph.
types¶
my $types = $par->types;
The Bidi types of the characters in this paragraph. Each element of @$types is a
constant in the $Text::Bidi::Type:: namespace.
levels¶
my $levels = $par->levels;
The embedding levels for this paragraph. Each element of @$levels is an integer.
my $bd = $par->bd;
The Text::Bidi object used to interface with libfribidi.
map¶
my $map = $par->map;
The map from the logical text to the visual, i.e., the values in $map are
indices in the logical string, so that the $i-th character of the visual
string is the character that occurs at "$map->[$i]" in the
logical string.
This is updated on each call to "visual", so that the map for the full
paragraph is correct only after calling "visual" for the whole text.
type_names¶
@types = $par->type_names;
Returns the list of bidi types as strings
is_rtl¶
my $rtl = $par->is_rtl;
Returns true if the direction of the paragraph is "RTL" (right to
left).
visual¶
my $visual = $par->visual($offset, $length, $flags);
Return the visual representation of the part of the paragraph
$par starting at
$offset and of
length
$length.
$par is a
Text::Bidi::Paragraph object. All arguments are optional, with
$offset defaulting to 0 and
$length
to the length till the end of the paragraph (see below from
$flags ).
Note that this method does not take care of right-justifying the text if the
paragraph direction is "RTL". Hence a typical application might look
as follows:
my $visual = $par->visual($offset, $width, $flags);
my $len = length($visual);
$visual = (' ' x ($width - $len)) . $visual if $par->is_rtl;
Note also that the length of the result might be strictly less than
$length .
The
$flags argument, if defined, should be either a hashref
or an integer. If it is a number, its meaning is the same as in
fribidi_reorder_line(3). A hashref is converted to the corresponding values
for keys whose value is true. The keys should be the same as the constants in
fribidi-types.h, with the prefix "FRIBIDI_FLAGS_" removed.
In addition, the
$flags hashref may contain lower-case
keys. The only one recognised at the moment is
break. Its value, if
given, should be a string at which the line should be broken. Hence, if this
key is given, the actual length is potentially reduced, so that the line
breaks at the given string (if possible). A typical value for
break is
' '.
SEE ALSO¶
Text::Bidi
AUTHOR¶
Moshe Kamensky <kamensky@cpan.org>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2013 by Moshe Kamensky.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.