462. How to display tooltip on buttons using GtkTooltip - Part 1 - plain text?

Problem

GtkTooltip is a new widget introduced in gtk+ 2.12. It was intended to replace the other widget GtkTooltips.

We'll learn about the new GtkTooltip through a series of examples. Theoretically, GtkTooltip works on any GtkWidget. I used GtkButton in this example. But you can try it on other widgets such as GtkLabel and GtkImage.

In this Part 1, I will show how to display tooltip as plain text on a GtkButton as shown below.

Key method used: GtkTooltip::set_text().

How to display tooltip on buttons using GtkTooltip - Part 1 - plain text?


Solution

Showing tooltip using GtkTooltip is a simple 3-step process:

  • Enable tooltip on the widget with GtkWidget::set_property('has-tooltip', true);
  • Connect to the signal 'query-tooltip'.
  • Display the tooltip in the signal handler. There are quite a number of ways to display the tooltip. In this Part 1, we use GtkTooltip::set_text() to display the tooltip as plain text.

Important Note: This only works for PHP-GTK v2.0 (or PHP-GTK2 compliled with gtk+ v2.12 and above. If you are using an older version, for linux, you may follow the step-by-step instructions to recompile php-gtk2 with gtk+ v2.12. For windows, please refer to How to install php gtk2 on windows?


Sample Code

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<?php
$window = new GtkWindow();
$window->set_title($argv[0]);
$window->connect_simple('destroy', array( 'Gtk', 'main_quit'));
$window->set_size_request(400,150);
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Display tooltip on GtkButton using GtkTooltip\n".
"   Part 1 - display tooltip with only plain text");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 60);
$vbox->pack_start($title, 0, 0);

$vbox->pack_start($hbox=new GtkHBox(), 0, 0);
create_button($hbox, 'Blue');
create_button($hbox, 'Green');
create_button($hbox, 'Yellow');

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

function create_button($hbox, $button_label) {
    $button = new GtkButton($button_label);
    $button->set_size_request(80, 32);
    $hbox->pack_start($button, 1, 0);
    $button->connect('clicked', "on_button", $button_label);

    $button->set_property('has-tooltip', true); // note 1
    $button->connect('query-tooltip', 'on_tooltip'); // note 2
}

function on_button($button, $button_label) {
    echo "You have clicked: $button_label!\n";
}

function on_tooltip($widget, $x, $y, $keyboard_mode, $tooltip) {
    $label = $widget->get_label();
    $tooltip->set_text("this is tooltip for button \"$label\""); // note 3
    return true;
}

?>

Output

As shown above.

 

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