Sample Code 399: How to get color values from gtkcolorbutton - Method 2? |
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Written by kksou
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Wednesday, 26 December 2007 |
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Problem I've written an example on getting the color values from GtkColorButton / GtkColorSelection in the article How to get color values from gtkcolorbutton?
Veronica from Argentina wrote to me with a better method of obtaining the color value from GtkColorButton as shown below:
Solution
- Create a standard GtkColorButton.
- Use the signal color-set to know when the user has selected a color.
- Get the selected color with GtkColorButton::get_color().
- Note that the value returned is a GdkColor.
- With a good understanding of XColor, Veronica shared with us the "magic formula" to convert the GdkColor to the familiar RGB color (in decimal) or hexadecimal.
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$window = new GtkWindow();
$window->set_title($argv[0]);
$window->set_size_request(400, 120);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());
// display title
$title = new GtkLabel("Get Color Values from GtkColorButton - Method 2");
$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);
$vbox->pack_start($title, 0);
$vbox->pack_start(new GtkLabel(), 0);
$hbox = new GtkHBox();
$vbox->pack_start($hbox, 0, 0);
$hbox->pack_start(new GtkLabel('Select Color'), 0);
$hbox->pack_start(new GtkLabel(' : '), 0);
$color_button = new GtkColorButton(); // note 1
$hbox->pack_start($color_button, 0);
$hbox->pack_start(new GtkLabel(' '), 0);
$selected_color = new GtkEntry();
$hbox->pack_start($selected_color, 0);
$color_button->connect('color-set', 'on_color_set'); // note 1
$window->show_all();
Gtk::main();
function on_color_set($color_button) {
print "on_color_set!\n";
$color = $color_button->get_color(); // note 3
print_r($color);
$gdk_red = $color->red; // note 4
$gdk_green = $color->green; // note 4
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Explanation
- Create the GtkColorSelection.
- Register the signal
color-set
- Retrieve the selected color. Note that this is in GdkColor.
- Retrieve the respective red, green and blue of the GdkColor. Note that these values range from 0-65535.
- Use Veronica's "magic formula" to convert the GdkColor to the standard RGB color we're familiar with (in decimal).
- Convert the RGB color to hexadecimal.
- Display the hexadecimal color value in the GtkEntry.
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