GIcon: GIO Reference Manual

GIcon

GIcon — Interface for icons

Functions

guint	g_icon_hash ()
gboolean	g_icon_equal ()
gchar *	g_icon_to_string ()
GIcon *	g_icon_new_for_string ()
GVariant *	g_icon_serialize ()
GIcon *	g_icon_deserialize ()

Types and Values

	GIcon
struct	GIconIface

Object Hierarchy

    GInterface
    ╰── GIcon

Prerequisites

GIcon requires GObject.

Known Derived Interfaces

GIcon is required by GLoadableIcon.

Known Implementations

GIcon is implemented by GBytesIcon, GEmblem, GEmblemedIcon, GFileIcon and GThemedIcon.

Includes

#include <gio/gio.h>

Description

GIcon is a very minimal interface for icons. It provides functions for checking the equality of two icons, hashing of icons and serializing an icon to and from strings.

GIcon does not provide the actual pixmap for the icon as this is out of GIO's scope, however implementations of GIcon may contain the name of an icon (see GThemedIcon), or the path to an icon (see GLoadableIcon).

To obtain a hash of a GIcon, see g_icon_hash().

To check if two GIcons are equal, see g_icon_equal().

For serializing a GIcon, use g_icon_serialize() and g_icon_deserialize().

If you want to consume GIcon (for example, in a toolkit) you must be prepared to handle at least the three following cases: GLoadableIcon, GThemedIcon and GEmblemedIcon. It may also make sense to have fast-paths for other cases (like handling GdkPixbuf directly, for example) but all compliant GIcon implementations outside of GIO must implement GLoadableIcon.

If your application or library provides one or more GIcon implementations you need to ensure that your new implementation also implements GLoadableIcon. Additionally, you must provide an implementation of g_icon_serialize() that gives a result that is understood by g_icon_deserialize(), yielding one of the built-in icon types.

Functions

g_icon_hash ()

guint
g_icon_hash (gconstpointer icon);

Gets a hash for an icon.

Virtual: hash

Parameters

icon

gconstpointer to an icon object.

[not nullable]

Returns

a guint containing a hash for the icon , suitable for use in a GHashTable or similar data structure.

g_icon_equal ()

gboolean
g_icon_equal (GIcon *icon1,
              GIcon *icon2);

Checks if two icons are equal.

Parameters

icon1	pointer to the first GIcon.	[nullable]
icon2	pointer to the second GIcon.	[nullable]

Returns

TRUE if icon1 is equal to icon2 . FALSE otherwise.

g_icon_to_string ()

gchar *
g_icon_to_string (GIcon *icon);

Generates a textual representation of icon that can be used for serialization such as when passing icon to a different process or saving it to persistent storage. Use g_icon_new_for_string() to get icon back from the returned string.

The encoding of the returned string is proprietary to GIcon except in the following two cases

If icon is a GFileIcon, the returned string is a native path (such as /path/to/my icon.png) without escaping if the GFile for icon is a native file. If the file is not native, the returned string is the result of g_file_get_uri() (such as sftp://path/to/my%20icon.png).
If icon is a GThemedIcon with exactly one name, the encoding is simply the name (such as network-server).

Virtual: to_tokens

Parameters

icon

a GIcon.

Returns

An allocated NUL-terminated UTF8 string or NULL if icon can't be serialized. Use g_free() to free.

[nullable]

Since: 2.20

g_icon_new_for_string ()

GIcon *
g_icon_new_for_string (const gchar *str,
                       GError **error);

Generate a GIcon instance from str . This function can fail if str is not valid - see g_icon_to_string() for discussion.

If your application or library provides one or more GIcon implementations you need to ensure that each GType is registered with the type system prior to calling g_icon_new_for_string().

Parameters

str	A string obtained via `g_icon_to_string()`.
error	Return location for error.

Returns

An object implementing the GIcon interface or NULL if error is set.

[transfer full]

Since: 2.20

g_icon_serialize ()

GVariant *
g_icon_serialize (GIcon *icon);

Serializes a GIcon into a GVariant. An equivalent GIcon can be retrieved back by calling g_icon_deserialize() on the returned value. As serialization will avoid using raw icon data when possible, it only makes sense to transfer the GVariant between processes on the same machine, (as opposed to over the network), and within the same file system namespace.

Parameters

icon

a GIcon

Returns

a GVariant, or NULL when serialization fails.

[transfer full]

Since: 2.38

g_icon_deserialize ()

GIcon *
g_icon_deserialize (GVariant *value);

Deserializes a GIcon previously serialized using g_icon_serialize().

Parameters

value

a GVariant created with g_icon_serialize()

Returns

a GIcon, or NULL when deserialization fails.

[transfer full]

Since: 2.38

Types and Values

GIcon

typedef struct _GIcon GIcon;

An abstract type that specifies an icon.

struct GIconIface

struct GIconIface {
  GTypeInterface g_iface;

  /* Virtual Table */

  guint       (* hash)        (GIcon   *icon);
  gboolean    (* equal)       (GIcon   *icon1,
                               GIcon   *icon2);
  gboolean    (* to_tokens)   (GIcon   *icon,
			       GPtrArray *tokens,
                               gint    *out_version);
  GIcon *     (* from_tokens) (gchar  **tokens,
                               gint     num_tokens,
                               gint     version,
                               GError **error);

  GVariant *  (* serialize)   (GIcon   *icon);
};

GIconIface is used to implement GIcon types for various different systems. See GThemedIcon and GLoadableIcon for examples of how to implement this interface.

Members

`hash` ()	A hash for a given GIcon.
`equal` ()	Checks if two GIcons are equal.
`to_tokens` ()	Serializes a GIcon into tokens. The tokens must not contain any whitespace. Don't implement if the GIcon can't be serialized (Since 2.20).
`from_tokens` ()	Constructs a GIcon from tokens. Set the GError if the tokens are malformed. Don't implement if the GIcon can't be serialized (Since 2.20).
`serialize` ()	Serializes a GIcon into a GVariant. Since: 2.38