Gtk2::Ex::TreeViewBits - various helpers for Gtk2::TreeView

 use Gtk2::Ex::TreeViewBits;

# Copyright 2007, 2008, 2009, 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::TreeViewBits;
use 5.008;
use strict;
use warnings;
use Carp;

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

our $VERSION = 43;


sub toggle_expand_row {
  my ($treeview, $path, $open_all) = @_;
  if ($treeview->row_expanded ($path)) {
    $treeview->collapse_row ($path);
  } else {
    $treeview->expand_row ($path, $open_all);
  }
}

sub remove_selected_rows {
  my ($treeview) = @_;
  my $model = $treeview->get_model;

  # foreach converting path to rowref frees each path as converted, whereas
  # a "map" keeps them all until the end, to perhaps save a couple of bytes
  # of peak memory use.
  #
  my @rows = $treeview->get_selection->get_selected_rows;  # paths
  foreach (@rows) {
    $_ = Gtk2::TreeRowReference->new($model,$_);  # rowrefs
  }

  # shifting frees each rowref as it's processed, to save
  # gtk_tree_row_ref_deleted() going through now removed rowrefs
  #
  while (my $rowref = shift @rows) {
    my $path = $rowref->get_path || next;  # if somehow gone away
    if (my $iter = $model->get_iter ($path)) {
      $model->remove ($iter);
    } else {
      carp 'Oops, selected row path "',$path->to_string,'" does not exist';
    }
  }
}

# In Gtk 2.12.12, when the row is bigger than the window, set_cursor()
# somehow likes to scroll to the opposite end of the row, presumably as a
# way of showing you the extents.  So if already positioned at the start of
# the row then set_cursor() scrolls to the end of it.  The scroll_to_cell()
# here moves back to the start of the row, but not before an unattractive
# bit of flashing.  There doesn't seem any clean way to avoid that.  It'd be
# much better if TreeView didn't draw immediately, but went through the
# queue_redraw / process_updates so as to collapse multiple programmatic
# changes.
#
sub scroll_cursor_to_path {
  my ($treeview, $path) = @_;
  ### scroll_cursor_to_path() path: $path->to_string
  my $model = $treeview->get_model || return;  # nothing to make visible

  # check path exists, in particular since ->scroll_to_cell() gives an
  # unsightly warning if the path is invalid
  $model->get_iter($path) or return;

  $treeview->expand_to_path ($path);
  $treeview->set_cursor ($path);

  my $bin_window = $treeview->get_bin_window || return; # if unrealized

  my ($bin_width, $bin_height) = $bin_window->get_size;
  ### $bin_height

  my $rect = $treeview->get_cell_area ($path, undef);
  ### path: "y=".$rect->y." height=".$rect->height." end=".($rect->y + $rect->height)

  if ($rect->y >= 0 && $rect->y + $rect->height <= $bin_height) {
    ### fully visible, don't scroll
    return;
  }
  my $row_align = ($rect->height > $bin_height ? 0 : 0.5);
  ### scroll align to: $row_align
  $treeview->scroll_to_cell ($path,
                             undef, # no column scroll
                             1,     # use_align
                             $row_align,
                             0);    # col_align
}

1;
__END__