151. How to add numbering in front of selected text in GtkTextView?

Problem

You want to add auto numbering in front of highlighted text in a GtkTextView as shown below:

How to add numbering in front of selected text in GtkTextView?


Solution


Sample Code

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<?php
$window = new GtkWindow();
$window->set_size_request(400, 240);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Add numbering in front of highlighted text\n");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 20);
$title->set_justify(Gtk::JUSTIFY_CENTER);
$alignment = new GtkAlignment(0.5, 0.5, 0, 0);
$alignment->add($title);
$vbox->pack_start($alignment);

$hbox = new GtkHBox();
$hbox->pack_start($button = new GtkButton('Add numbering'), 0);
$vbox->pack_start($hbox, 0);
$button->connect('clicked', 'on_button'); // note 1

// Create a new buffer and a new view to show the buffer.
$buffer = new GtkTextBuffer();
$view = new GtkTextView();
$view->set_buffer($buffer);
$view->modify_font(new PangoFontDescription("Arial 10"));
$view->set_wrap_mode(Gtk::WRAP_WORD);

$scrolled_win = new GtkScrolledWindow();
$scrolled_win->set_policy( Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);
$vbox->pack_start($scrolled_win);
$scrolled_win->add($view);

$window->show_all();
Gtk::main();

function on_button($button) {
    global $view, $buffer;
    list($start_iter, $end_iter) = $buffer->get_selection_bounds(); // note 2
    if ($start_iter==null || $end_iter==null) {
         $cursor_pos = $buffer->get_mark('insert'); // note 3
         $start_iter = $end_iter = $buffer->get_iter_at_mark($cursor_pos); // note 3
    }

    $start_line = $start_iter->get_line(); // note 4
    $end_line = $end_iter->get_line(); // note 4

    $n = 1;
    $iter = $start_iter;
    for ($i=$start_line; $i<=$end_line; ++$i) {
        $iter->set_line($i); // note 5
        $iter->forward_word_end(); // note 6
        $iter->backward_word_start(); // note 6
        $buffer->insert($iter, "$n. ", -1); // note 7
        ++$n;
    }
}

?>

Output

As shown above.
 

Explanation

  1. Set up the "Add numbering" button.
  2. Get the start and end iter of the selection bounds.
  3. If user didn't select any text, use the current cursor position as start and end iter.
  4. Get the line number of the start and end iter.
  5. Move the iter to the start of the line.
  6. Move the iter to the first non-space character.
  7. Add the number.

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