Search code examples
perlgtk3

How to set the background color in a Gtk3::TreeViewColumn?


I tried to set the background color in a Gtk3::TreeViewColumn:

my $red = Gtk3::Gdk::RGBA->new(1, 0.8, 0.8, 1);
my $renderer = Gtk3::CellRendererText->new;
my $column = Gtk3::TreeViewColumn->new_with_attributes
    ($c, $renderer, text => $n, background => $red);

But I get the error:

Gtk-CRITICAL **: 09:54:09.834: gtk_list_store_get_value: assertion 'column < priv->n_columns' failed
GLib-GObject-CRITICAL **: g_value_transform: assertion 'G_IS_VALUE (src_value)' failed at /usr/share/perl5/Gtk3.pm line 568.
GLib-GObject-WARNING **: unable to set property 'background' of type 'gchararray' from value of type '(null)' at /usr/share/perl5/Gtk3.pm line 568.

When I create the color this way, I get the same error:

my $red2 = Gtk3::Gdk::RGBA::parse ('#FF0000');

Can anybody explain how to set the background color?

Complete example:

#! /usr/bin/perl
use strict;
use warnings;
use utf8;

use Gtk3 -init;
use Glib 'TRUE', 'FALSE';

my @COLUMNS = (
  'a',
  'b',
  'c');

my $red = Gtk3::Gdk::RGBA->new(1, 0, 0, 1);
my $red2 = Gtk3::Gdk::RGBA::parse ('#F00');

my $window = Gtk3::Window->new ('toplevel');

my $notebook = Gtk3::Notebook->new;
$window->add($notebook);

my $sw = Gtk3::ScrolledWindow->new (undef, undef);
$notebook->append_page ($sw, Gtk3::Label->new ("tab"));

my $model = Gtk3::ListStore->new (('Glib::String') x scalar @COLUMNS);

my $row = $model->append ();
$model->set ($row,
             0, "a",
             1, "b",
             2, "c");

my $treeview = Gtk3::TreeView->new($model);
$sw->add($treeview);

while (my ($n, $c) = each @COLUMNS) {
  my $renderer = Gtk3::CellRendererText->new;
  my $column = Gtk3::TreeViewColumn->new_with_attributes
      ($c, $renderer, text => $n, background => $red);
  $treeview->append_column($column);
}

$window->show_all;
Gtk3->main();

Solution

  • The problem is this line:

    my $column = Gtk3::TreeViewColumn->new_with_attributes
      ($c, $renderer, text => $n, background => $red);
    

    Here, the background attribute expects a Gtk3::ListStore index, but you are not giving an integer index, rather you are supplying the RGBA object $red.

    Here is an example of how you can do it by adding a dummy column to the Gtk::ListStore containing the color as a RGB string:

    use feature qw(say);
    use strict;
    use warnings;
    use Gtk3 -init;
    use Glib 'TRUE', 'FALSE';
    
    my @COLUMNS = qw( a b c );
    my $ncols = scalar @COLUMNS;
    
    my $red = "#f00";
    my $window = Gtk3::Window->new ('toplevel');
    my $notebook = Gtk3::Notebook->new;
    $window->add($notebook);
    my $sw = Gtk3::ScrolledWindow->new (undef, undef);
    $notebook->append_page ($sw, Gtk3::Label->new ("tab"));
    
    my $model = Gtk3::ListStore->new ((('Glib::String') x $ncols), 'Glib::String');
    my $row = $model->append ();
    $model->set ($row, (map {($_, $COLUMNS[$_])} 0..$#COLUMNS), $ncols, $red);
    my $treeview = Gtk3::TreeView->new($model);
    $sw->add($treeview);
    while (my ($n, $c) = each @COLUMNS) {
      my $renderer = Gtk3::CellRendererText->new;
      my $column = Gtk3::TreeViewColumn->new_with_attributes
          ($c, $renderer, text => $n, background => $ncols);
      $treeview->append_column($column);
    }
    $window->signal_connect( destroy  => sub { Gtk3->main_quit() } );
    $window->show_all;
    Gtk3->main();
    

    See also Python 3 and Gtk+3 - issue with TreeView and alternate colors of rows