Image


Object Hierarchy:

Object hierarchy for Image

Description:

public class Image : Misc, Implementor, Buildable

The Image widget displays an image.

Various kinds of object can be displayed as an image; most typically, you would load a Pixbuf ("pixel buffer") from a file, and then display that. There’s a convenience function to do this, Image.from_file, used as follows:

  GtkWidget *image;
image = gtk_image_new_from_file ("myfile.png");
If the file isn’t loaded successfully, the image will contain a “broken image” icon similar to that used in many web browsers. If you want to handle errors in loading the file yourself, for example by displaying an error message, then load the image with Pixbuf.from_file, then create the Image with Image.from_pixbuf.

The image file may contain an animation, if so the Image will display an animation ( PixbufAnimation) instead of a static image.

Image is a subclass of Misc, which implies that you can align it (center, left, right) and add padding to it, using Misc methods.

Image is a “no window” widget (has no Window of its own), so by default does not receive events. If you want to receive events on the image, such as button clicks, place the image inside a EventBox, then connect to the event signals on the event box.

Handling button press events on a Image.

  static gboolean
button_press_callback (GtkWidget *event_box,
GdkEventButton *event,
gpointer data)
{
g_print ("Event box clicked at coordinates %f,%f\n",
event->x, event->y);

// Returning TRUE means we handled the event, so the signal
// emission should be stopped (don’t call any further callbacks
// that may be connected). Return FALSE to continue invoking callbacks.
return TRUE;
}

static GtkWidget*
create_image (void)
{
GtkWidget *image;
GtkWidget *event_box;

image = gtk_image_new_from_file ("myfile.png");

event_box = gtk_event_box_new ();

gtk_container_add (GTK_CONTAINER (event_box), image);

g_signal_connect (G_OBJECT (event_box),
"button_press_event",
G_CALLBACK (button_press_callback),
image);

return image;
}
When handling events on the event box, keep in mind that coordinates in the image may be different from event box coordinates due to the alignment and padding settings on the image (see Misc). The simplest way to solve this is to set the alignment to 0.0 (left/top), and set the padding to zero. Then the origin of the image will be the same as the origin of the event box.

Sometimes an application will want to avoid depending on external data files, such as image files. GTK+ comes with a program to avoid this, called “gdk-pixbuf-csource”. This library allows you to convert an image into a C variable declaration, which can then be loaded into a Pixbuf using Pixbuf.from_inline.

CSS nodes

GtkImage has a single CSS node with the name image.

GtkImage

Example: Image:

public class Application : Gtk.Window {
public Application (string img_path) {
// Prepare Gtk.Window:
this.title = "My Gtk.Image";
this.window_position = Gtk.WindowPosition.CENTER;
this.destroy.connect (Gtk.main_quit);
this.set_default_size (350, 70);

// The image:
Gtk.Image image = new Gtk.Image ();
image.set_from_file (img_path);
this.add (image);
}

public static int main (string[] args) {
Gtk.init (ref args);

string img_path = "";
if (args[1] != null) {
img_path = args[1];
}

Application app = new Application (img_path);
app.show_all ();
Gtk.main ();
return 0;
}
}

valac --pkg gtk+-3.0 Gtk.Image.vala


Namespace: Gtk
Package: gtk+-3.0

Content:

Properties:

Creation methods:

Methods:

Inherited Members:

All known members inherited from class Gtk.Misc
All known members inherited from class Gtk.Widget
All known members inherited from interface Atk.Implementor