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Problem This is in response to Andreas' Post titled "Possible to add not tiled backgrounds".
Suppose you want to have a single background image that always stayed at the bottom right corner of a GtkWindow (no matter how the user changes the window size).
This article presents a more advanced and flexible solution that uses GdkDrawable::draw_pixbuf().
Also, I purposely chose an example (using the sample code from How to align GtkEntry fields - Part 2?) with a mixture of GtkVBox, GtkTable, GtkLabel and GtkEntry to show that this method works with any GtkWindow contents as shown below:
Solution
Sample Code Note: The following image file is required by the sample code below. Please save a copy of the image files and put them in the same directory where you store the sample code.
 | sample6_360a.png |
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$window = new GtkWindow();
$window->set_size_request(480, 240);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());
// display title
$title = new GtkLabel(
" Place a background image in GtkWindow\n".
"Part 6 - align bottom right - using GdkDrawable::draw_pixbuf()");
$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, 0);
$fields = array('Item number', 'Item Description', 'Unit price', 'Quantity');
$field_size = array(120, 200, 80, 80);
$entry = array(); // to store the text entries
$table = new GtkTable();
display_table($table, $fields, $field_size); // display the table
$vbox->pack_start($table);
// create a submit button
$button = new GtkButton('Submit');
$button->set_size_request(60, 28);
$button->connect('clicked', 'on_click');
$row = count($fields);
$alignment = new GtkAlignment(0, 0.5, 0, 0);
$alignment->add($button);
$table->attach($alignment, 1, 2, $row, $row+1);
$window->connect('expose_event', 'expose_event'); // note 1
$window->show_all();
Gtk::main();
function display_table($table, $fields, $field_size) {
global $entry;
$row = 0;
foreach ($fields as $field) {
$label = new GtkLabel(" $field: ");
$alignment = new GtkAlignment(1, .5, 0, 0);
$alignment->add($label);
$table->attach($alignment, 0, 1, $row, $row+1,
Gtk::FILL, Gtk::SHRINK, 0, 0);
$entry[$row] = new GtkEntry();
$alignment = new GtkAlignment(0, .5, 0, 0);
$alignment->add($entry[$row]);
$entry[$row]->set_size_request($field_size[$row], -1);
$table->attach($alignment, 1, 2, $row, $row+1);
++$row;
}
}
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- Note that this is only 70% of the sample code. You have to be a registered member to see the entire sample code. Please login or register.
- Registration is free and immediate.
- Have some doubt about the registration? Please read this forum article.
Explanation We make use of the base code from How to align GtkEntry fields - Part 2? which contains a mixture of GtkVBox, GtkTable, GtkLabel and GtkEntry.
What's new here:
- Register for the signal 'expose_event'.
- Load the background image. This works with all standard image file format such as .gif, .jpg or .png.
- Calculate where to place the background image. Note that here we leave a 10-pixel margins between the image and the bottom-right margins.
- Surprised by this one-liner?! Yes, this is the line that sets the background image! This works for the alpha/Gnope version too!
Note
Try compare this method with that described in How to place a background image in GtkWindow - Part 4 - align bottom right - using GtkStyle? and you'll understand why this method is more advanced and seemingly "better":
- Did you notice that this method supports transparencies in .png and .gif file?
- As we're drawing each image directly onto the underlying GdkWindow, there's no issue of tiled images.
- You can use the image file as-is. When using the GtkStyle method, you have to "pad" the image to 1920x1200.
- You can position the image to the exact location you want.
- Try changing the window size. Unlike the method described in How to place a background image in GtkWindow - Part 4 - align bottom right - using GtkStyle? with this method, you will find that the background image will always stay at the bottom right of the window.
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