195. How to set the background to original default color?

Problem

You have set up label 1 with a yellow background color as shown below:

How to set the background to original default color?

You would like to set label 1 back to the original default background color at the click of a button as shown below. (Note: label 2 is for comparison.)


Solution

  • We can get the original default background color before changing the color of label 1 with GtkWidget::get_style().

Sample Code

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<?php
$window = &new GtkWindow();
$window->connect_simple('destroy', array( 'Gtk', 'main_quit'));
$window->set_size_request(400,200);
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Set Background to Original Default Color");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 40);
$title->set_justify(Gtk::JUSTIFY_CENTER);
$alignment = new GtkAlignment(0.5, 0, 0, 0);
$alignment->add($title);
$vbox->pack_start($alignment, 0, 0);
$vbox->pack_start(new GtkLabel(), 0, 0);

$window->realize(); // note 1
$org_bg = $window->get_style()->bg[Gtk::STATE_NORMAL]; // note 2

// create label 1 and 2
$label1 = new GtkLabel("This is label 1");
$eventbox = new GtkEventBox();
$eventbox->modify_bg(Gtk::STATE_NORMAL, GdkColor::parse('#ffff00'));
$eventbox->add($label1);

$hbox = new GtkHBox();
$hbox->set_size_request(400, 80);
$hbox->pack_start($eventbox);
$hbox->pack_start($label2 = new GtkLabel(
    "This is label 2\nin original\ndefault bg color"));
$vbox->pack_start($hbox, 0);

// create buttons
$vbox->pack_start($button1 = new GtkButton('label in yellow'), 0);
$button1->connect('clicked', 'on_click', 'yellow');

$vbox->pack_start($button2 = new GtkButton(
    'label in original default bg color'), 0);
$button2->connect('clicked', 'on_click', 'org_color');

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

function on_click($button, $color) {
    global $eventbox;
    if ($color=='yellow') {
        $eventbox->modify_bg(Gtk::STATE_NORMAL, GdkColor::parse('#ffff00'));
    } else {
        global $org_bg;
        $eventbox->modify_bg(Gtk::STATE_NORMAL, $org_bg); // note 3
    }
}
?>

Output

As shown above.

 

Explanation

  1. Remember to realize the window before making a copy of the original background color. Try commenting this line out and you will find that you won't get the original color.
  2. Make a copy of the original background color.
  3. Set label 1 back to the original background color.

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