Gtk.IconTheme – gtk+-3.0 – Vala Binding Reference

Description:

[ CCode ( type_id = "gtk_icon_theme_get_type ()" ) ]
public class IconTheme : Object

IconTheme 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 fallback icon theme, named `hicolor`, where applications should install their icons, but additional icon themes can be installed as operating system vendors and users choose.

Named icons are similar to the deprecated Stock Items, 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_stock_ok or gtk_stock_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 IconSize enumeration, or by custom sizes defined by register, 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_stock_go_forward uses the two themed icons “gtk-stock-go-forward-ltr” and “gtk-stock-go-forward-rtl”.)

In many cases, named themes are used indirectly, via Image or stock items, rather than directly, but looking up icons directly is also simple. The IconTheme object acts as a database of all the icons in the current theme. You can create new IconTheme objects, but it’s much more efficient to use the standard icon theme for the Screen so that the icon information is shared with other people looking up icons.

GError *error = NULL;
GtkIconTheme *icon_theme;
GdkPixbuf *pixbuf;

icon_theme = gtk_icon_theme_get_default ();
pixbuf = gtk_icon_theme_load_icon (icon_theme,
																	 "my-icon-name", // icon name
																	 48, // icon size
																	 0,	// flags
																	 &error);
if (!pixbuf)
	{
		g_warning ("Couldn’t load icon: %s", error->message);
		g_error_free (error);
	}
else
	{
		// Use the pixbuf
		g_object_unref (pixbuf);
	}

Namespace: Gtk

Package: gtk+-3.0

Content:

Static methods:

public static void add_builtin_icon (string icon_name, int size, Pixbuf pixbuf)

Registers a built-in icon for icon theme lookups.

public static unowned IconTheme get_default ()

Gets the icon theme for the default screen.

public static unowned IconTheme get_for_screen (Screen screen)

Gets the icon theme object associated with screen; if this function has not previously been called for the given screen, a new icon theme object will be created and associated with the screen.

Creation methods:

public IconTheme ()

Creates a new icon theme object.

Methods:

public void add_resource_path (string path)

Adds a resource path that will be looked at when looking for icons, similar to search paths.

public void append_search_path (string path)

Appends a directory to the search path.

public IconInfo? choose_icon (string[] icon_names, int size, IconLookupFlags flags)

Looks up a named icon and returns a IconInfo containing information such as the filename of the icon.

public IconInfo? choose_icon_for_scale (string[] icon_names, int size, int scale, IconLookupFlags flags)

Looks up a named icon for a particular window scale and returns a IconInfo containing information such as the filename of the icon.

public string? get_example_icon_name ()

Gets the name of an icon that is representative of the current theme ( for instance, to use when presenting a list of themes to the user.

public int[] get_icon_sizes (string icon_name)

Returns an array of integers describing the sizes at which the icon is available without scaling.

public void get_search_path (out string[] path)

Gets the current search path.

public bool has_icon (string icon_name)

Checks whether an icon theme includes an icon for a particular name.

public List<string> list_contexts ()

Gets the list of contexts available within the current hierarchy of icon themes.

public List<string> list_icons (string? context)

Lists the icons in the current icon theme.

public Pixbuf? load_icon (string icon_name, int size, IconLookupFlags flags) throws Error

Looks up an icon in an icon theme, scales it to the given size and renders it into a pixbuf.

public Pixbuf? load_icon_for_scale (string icon_name, int size, int scale, IconLookupFlags flags) throws Error

Looks up an icon in an icon theme for a particular window scale, scales it to the given size and renders it into a pixbuf.

public Surface? load_surface (string icon_name, int size, int scale, Window? for_window, IconLookupFlags flags) throws Error

Looks up an icon in an icon theme for a particular window scale, scales it to the given size and renders it into a cairo surface.

public IconInfo? lookup_by_gicon (Icon icon, int size, IconLookupFlags flags)

Looks up an icon and returns a IconInfo containing information such as the filename of the icon.

public IconInfo? lookup_by_gicon_for_scale (Icon icon, int size, int scale, IconLookupFlags flags)

Looks up an icon and returns a IconInfo containing information such as the filename of the icon.

public IconInfo? lookup_icon (string icon_name, int size, IconLookupFlags flags)

Looks up a named icon and returns a IconInfo containing information such as the filename of the icon.

public IconInfo? lookup_icon_for_scale (string icon_name, int size, int scale, IconLookupFlags flags)

Looks up a named icon for a particular window scale and returns a IconInfo containing information such as the filename of the icon.

public void prepend_search_path (string path)

Prepends a directory to the search path.

public bool rescan_if_needed ()

Checks to see if the icon theme has changed; if it has, any currently cached information is discarded and will be reloaded next time this is accessed.

public void set_custom_theme (string? theme_name)

Sets the name of the icon theme that the IconTheme object uses overriding system configuration.

public void set_screen (Screen screen)

Sets the screen for an icon theme; the screen is used to track the user’s currently configured icon theme, which might be different for different screens.

public void set_search_path (string[] path)

Sets the search path for the icon theme object.

Signals:

public virtual signal void changed ()

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

Inherited Members:

All known members inherited from class GLib.Object

@get
@new
@ref
@set
add_toggle_ref
add_weak_pointer
bind_property
connect
constructed
disconnect
dispose
dup_data
dup_qdata
force_floating
freeze_notify
get_class
get_data

get_property
get_qdata
get_type
getv
interface_find_property
interface_install_property
interface_list_properties
is_floating
new_valist
new_with_properties
newv
notify
notify_property
ref_count
ref_sink
remove_toggle_ref
remove_weak_pointer

replace_data
replace_qdata
set_data
set_data_full
set_property
set_qdata
set_qdata_full
set_valist
setv
steal_data
steal_qdata
thaw_notify
unref
watch_closure
weak_ref
weak_unref

IconTheme