GI.Gio.Interfaces.Icon

Icon 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.

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

To obtain a hash of a Icon, see iconHash.

To check if two GIcons are equal, see iconEqual.

For serializing a Icon, use iconSerialize and iconDeserialize.

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

If your application or library provides one or more Icon implementations you need to ensure that your new implementation also implements LoadableIcon. Additionally, you must provide an implementation of iconSerialize that gives a result that is understood by iconDeserialize, yielding one of the built-in icon types.

Exported types

newtype Icon

Memory-managed wrapper type.

Constructors

Icon (ManagedPtr Icon)

Instances

GObject Icon

Defined in GI.Gio.Interfaces.Icon

Methods

gobjectType :: IO GType

HasParentTypes Icon

Defined in GI.Gio.Interfaces.Icon

type ParentTypes Icon

Defined in GI.Gio.Interfaces.Icon

type ParentTypes Icon = Object ': ([] :: [Type])

noIcon :: Maybe Icon

A convenience alias for Nothing :: Maybe Icon.

class (GObject o, IsDescendantOf Icon o) => IsIcon o

Type class for types which can be safely cast to Icon, for instance with toIcon.

Instances

(GObject o, IsDescendantOf Icon o) => IsIcon o

Defined in GI.Gio.Interfaces.Icon

toIcon :: (MonadIO m, IsIcon o) => o -> m Icon

Cast to Icon, for types for which this is known to be safe. For general casts, use castTo.

Methods

deserialize

iconDeserialize

Arguments

:: (HasCallStack, MonadIO m)

=> GVariant

value: a GVariant created with iconSerialize

-> m Icon

Returns: a Icon, or Nothing when deserialization fails.

Deserializes a Icon previously serialized using iconSerialize.

Since: 2.38

equal

iconEqual

Arguments

:: (HasCallStack, MonadIO m, IsIcon a, IsIcon b)

=> a

icon1: pointer to the first Icon.

-> Maybe b

icon2: pointer to the second Icon.

-> m Bool

Returns: True if icon1 is equal to icon2. False otherwise.

Checks if two icons are equal.

hash

iconHash

Arguments

:: (HasCallStack, MonadIO m)

=> Ptr ()

icon: gconstpointer to an icon object.

-> m Word32

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

Gets a hash for an icon.

newForString

iconNewForString

Arguments

:: (HasCallStack, MonadIO m)

=> Text

str: A string obtained via iconToString.

-> m Icon

Returns: An object implementing the Icon interface or Nothing if error is set. (Can throw GError)

Generate a Icon instance from str. This function can fail if str is not valid - see iconToString for discussion.

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

Since: 2.20

serialize

iconSerialize

Arguments

:: (HasCallStack, MonadIO m, IsIcon a)

=> a

icon: a Icon

-> m GVariant

Returns: a GVariant, or Nothing when serialization fails.

Serializes a Icon into a GVariant. An equivalent Icon can be retrieved back by calling iconDeserialize 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.

Since: 2.38

toString

iconToString

Arguments

:: (HasCallStack, MonadIO m, IsIcon a)

=> a

icon: a Icon.

-> m (Maybe Text)

Returns: An allocated NUL-terminated UTF8 string or Nothing if icon can't be serialized. Use free to free.

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 iconNewForString to get icon back from the returned string.

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

• If icon is a FileIcon, the returned string is a native path (such as /path/to/my icon.png) without escaping if the File for icon is a native file. If the file is not native, the returned string is the result of fileGetUri (such as sftp://path/to/my%20icon.png).
• If icon is a ThemedIcon with exactly one name and no fallbacks, the encoding is simply the name (such as network-server).

Since: 2.20