g-object, common-lisp:standard-object, common-lisp:t

None

The gtk-icon-theme class provides a facility for looking up icons by name and size. The main reason for using a name rather than simply providing a filename is to allow different icons to be used depending on what icon theme is selected by the user. The operation of icon themes on Linux and Unix follows the Icon Theme Specification. There is a default icon theme, named Hicolor where applications should install their icons, but more additional application themes can be installed as operating system vendors and users choose.

Named icons are similar to the Themeable Stock Images facility, and the distinction between the two may be a bit confusing. A few things to keep in mind:

• Stock images usually are used in conjunction with Stock Items, such as "gtk-ok" or "gtk-open". Named icons are easier to set up and therefore are more useful for new icons that an application wants to add, such as application icons or window icons.
• Stock images can only be loaded at the symbolic sizes defined by the gtk-icon-size enumeration, or by custom sizes defined by the gtk-icon-size-register function, while named icons are more flexible and any pixel size can be specified.
• Because stock images are closely tied to stock items, and thus to actions in the user interface, stock images may come in multiple variants for different widget states or writing directions.

A good rule of thumb is that if there is a stock image for what you want to use, use it, otherwise use a named icon. It turns out that internally stock images are generally defined in terms of one or more named icons. An example of the more than one case is icons that depend on writing direction; "gtk-go-forward" uses the two themed icons "gtk-stock-go-forward-ltr" and "gtk-stock-go-forward-rtl".

In many cases, named icon themes are used indirectly, via the gtk-image widget or stock items, rather than directly, but looking up icons directly is also simple. The icon theme acts as a database of all the icons in the current icon theme. You can create new icon themes, but its much more efficient to use the standard icon theme for the gdk-screen object so that the icon information is shared with other people looking up icons. In the case where the default screen is being used, looking up an icon can be as simple as:

(let* ((theme (gtk-icon-theme-default))
       (pixbuf (gtk-icon-theme-load-icon theme
                                         "gtk-ok"    ; icon name
                                         48          ; size
                                         0)))        ; no flags
   ... )    

The "changed" signal

 lambda (theme)    :run-last      

Emitted when the current icon theme is switched or GTK detects that a change has occurred in the contents of the current icon theme.

theme

The gtk-icon-theme object.