Gtk2::Ex::TextBufferBits - helpers for Gtk2::TextBuffer objects

 use Gtk2::Ex::TextBufferBits;

# Copyright 2010, 2011 Kevin Ryde

# This file is part of Gtk2-Ex-WidgetBits.
#
# Gtk2-Ex-WidgetBits is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3, or (at your option) any later
# version.
#
# Gtk2-Ex-WidgetBits 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 General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with Gtk2-Ex-WidgetBits.  If not, see <http://www.gnu.org/licenses/>.


package Gtk2::Ex::TextBufferBits;
use 5.008;
use strict;
use warnings;

# uncomment this to run the ### lines
#use Smart::Comments;

our $VERSION = 43;

sub replace_lines {
  my ($textbuf, $str) = @_;

  require Glib::Ex::FreezeNotify;
  my $freezer = Glib::Ex::FreezeNotify->new ($textbuf,
                                             $textbuf->get_insert,
                                             $textbuf->get_selection_bound);

  my ($ins_line, $ins_col) = _mark_to_lineandcol ($textbuf->get_insert);
  my ($sel_line, $sel_col) = _mark_to_lineandcol ($textbuf->get_selection_bound);
  ### ins/sel: "$ins_line,$ins_col $sel_line,$sel_col "

  my $pos = 0;
  my $iter = $textbuf->get_start_iter;
  if (! $iter->is_end) {
    for (;;) {
      ### at: $pos, $iter->get_offset

      my $endpos = index ($str, "\n", $pos);
      if ($endpos < 0) {
        ### str no more newlines, delete through: $textbuf->get_end_iter->get_offset
        $textbuf->delete ($iter, $textbuf->get_end_iter);
        last;
      }
      ### endpos: $endpos

      # forward_to_line_end() goes to next line if already at line end, so test
      if (! $iter->ends_line) {
        my $enditer = $iter->copy;
        $enditer->forward_to_line_end;
        ### delete to enditer: $enditer->get_offset, $textbuf->get_text($iter,$enditer,1)
        $textbuf->delete ($iter, $enditer);
      }

      ### insert: substr($str, $pos, $endpos-$pos)
      $textbuf->insert ($iter, substr($str, $pos, $endpos-$pos));

      $pos = $endpos;
      if ($iter->is_end) {
        ### buffer end, no final newline
        last;
      }
      $pos++;
      if (! $iter->forward_line) {
        ### buffer end, with final newline
        last;
      }
    }
  }

  ### insert final: $pos, substr($str, $pos)
  if ($pos < length($str)) {
    $textbuf->insert ($iter, substr ($str, $pos));
  }

  $textbuf->select_range (_lineandcol_to_iter ($textbuf, $ins_line, $ins_col),
                          _lineandcol_to_iter ($textbuf, $sel_line, $sel_col));
}

# $mark is a Gtk2::TextMark
# return ($line, $column) of its current position
sub _mark_to_lineandcol {
  my ($mark) = @_;
  my $textbuf = $mark->get_buffer || return;
  my $iter = $textbuf->get_iter_at_mark ($mark);
  ### _mark_to_lineandcol(): $iter->get_offset
  if ($iter->is_end) {
    return (-1, -1);
  } else {
    return ($iter->get_line,
            ! $mark->get_left_gravity && $iter->ends_line
            ? -1 : $iter->get_line_offset);
  }
}

# $textbuf is a Gtk2::TextBuffer
# return a Gtk2::TextIter at $line,$column in that buffer
sub _lineandcol_to_iter {
  my ($textbuf, $line, $column) = @_;
  if ($line == -1) {
    return $textbuf->get_end_iter;
  }
  my $iter = $textbuf->get_iter_at_line ($line);
  if ($column == -1 || $column >= $iter->get_chars_in_line) {
    unless ($iter->ends_line) { $iter->forward_to_line_end; }
  } else {
    $iter->forward_chars ($column);
  }
  ### result: "$line,$column -> ".$iter->get_offset
  return $iter;
}


1;
__END__