Class
GeglMetadataStore
Instance methods
gegl_metadata_store_get_string
A slightly more efficient version of gegl_metadata_store_get_value()
for string values avoiding a duplication. Otherwise it behaves the same gegl_metadata_store_get_value().
gegl_metadata_store_get_value
Retrieve the metadata value. value must be initialised with a compatible
type. If the value is unset or has not been previously declared value is
unchanged and an error message is logged.
gegl_metadata_store_has_value
Test whether the GeglMetadataStore contains a value for the specified name.
gegl_metadata_store_notify
Gegl_metadata_store_notify() is called by subclasses when the value of a
metadata variable changes. It emits the ::changed signal with the variable
name as the detail parameter. Set shadow = TRUE if variable is shadowed
by a property so that a notify signal is emitted with the property name as
the detail parameter.
gegl_metadata_store_set_string
A slightly more efficient version of gegl_metadata_store_set_value()
for string values avoiding a duplication. Otherwise it behaves the same gegl_metadata_store_set_value().
gegl_metadata_store_set_value
Set the specified metadata value. If value is NULL the default value from
the associated GParamSpec is used. This operation will fail if the value
has not been previously declared. A changed::name signal is emitted when
the value is set. If the value is shadowed by a property a notify::name
signal is also emitted.
Methods inherited from GeglMetadata (9)
gegl_metadata_get_resolution
Retrieve resolution from the application image metadata. Intended for use
by the image file writer. If resolution is not supported by the application
or if the operation fails FALSE is returned and the resolution values are
not updated.
gegl_metadata_iter_get_value
Retrieve image file metadata from the application. Intended for use by the
image file writer. If the operation fails it returns FALSE and value is
not updated.
gegl_metadata_iter_init
Initialise an iterator to find all supported metadata keys.
gegl_metadata_iter_lookup
Look up the specified key and initialise an iterator to reference the
associated metadata. The iterator is used in conjunction with
gegl_metadata_set_value() and gegl_metadata_get_value(). Note that this
iterator is not valid for gegl_metadata_iter_next().
gegl_metadata_iter_next
Move the iterator to the next metadata item.
gegl_metadata_iter_set_value
Set application data retrieved from image file’s metadata. Intended for use
by the image file reader. If the operation fails it returns FALSE and
value is ignored.
gegl_metadata_register_map
Set the name of the file module and pass an array of mappings from file-format specific metadata names to those used by Gegl. A GValue transformation function may be supplied, e.g. to parse or format timestamps.
gegl_metadata_set_resolution
Set resolution retrieved from image file’s metadata. Intended for use by
the image file reader. If resolution is not supported by the application or
if the operation fails FALSE is returned and the values are ignored.
gegl_metadata_unregister_map
Unregister the file module mappings and any further mappings added or modified by the application. This should be called after the file module completes operations.
Properties
Gegl.MetadataStore:file-module-name
Current file loader/saver module name. Valid only while a GeglMetadata
mapping is registered. This property is mainly provided for use in signal handlers.
Gegl.MetadataStore:resolution-unit
A GeglResolutionUnit specifying units for the image resolution (density).
Signals
Gegl.MetadataStore::changed
::changed is emitted when a metadata value is changed. This is analogous
to the GObject::notify signal.
Gegl.MetadataStore::generate-value
If a signal handler is connected to ::generate-value a signal is emitted
when the file module accesses a value using gegl_metadata_get_value().
The signal handler must generate a value of the type specified in the pspec
argument. The signal handler’s return value indicates the success of the operation.
Gegl.MetadataStore::mapped
::mapped is emitted after a file module registers a mapping and before
other processing takes place. An application may respond to the signal by
registering additional mappings or overriding existing values, for example
it might override the TIFF ImageDescription tag to format multiple metadata
values into the description.
Gegl.MetadataStore::parse-value
If a signal handler is connected to ::parse-value a signal is emitted when
the file module accesses a value using gegl_metadata_set_value(). The
signal handler should parse the value supplied in the GValue and may set
any number of metadata values using gegl_metadata_store_set_value().
Gegl.MetadataStore::unmapped
::unmapped is emitted when a file module tries to look up an unmapped
metadata name. When the handler returns a second attempt is made to look
up the metadata.
Signals inherited from GObject (1)
GObject::notify
The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.
Class structure
struct GeglMetadataStoreClass {
void (* _declare) (
GeglMetadataStore* self,
GParamSpec* pspec,
gboolean shadow
);
GParamSpec* (* pspec) (
GeglMetadataStore* self,
const gchar* name
);
void (* set_value) (
GeglMetadataStore* self,
const gchar* name,
const GValue* value
);
const GValue* (* _get_value) (
GeglMetadataStore* self,
const gchar* name
);
gboolean (* has_value) (
GeglMetadataStore* self,
const gchar* name
);
void (* register_hook) (
GeglMetadataStore* self,
const gchar* file_module_name,
guint flags
);
gboolean (* parse_value) (
GeglMetadataStore* self,
GParamSpec* pspec,
GValueTransform transform,
const GValue* value
);
gboolean (* generate_value) (
GeglMetadataStore* self,
GParamSpec* pspec,
GValueTransform transform,
GValue* value
);
}The class structure for the GeglMetadataStore.
Class members
_declare: void (* _declare) ( GeglMetadataStore* self, GParamSpec* pspec, gboolean shadow )- No description available.
pspec: GParamSpec* (* pspec) ( GeglMetadataStore* self, const gchar* name )- No description available.
set_value: void (* set_value) ( GeglMetadataStore* self, const gchar* name, const GValue* value )- No description available.
_get_value: const GValue* (* _get_value) ( GeglMetadataStore* self, const gchar* name )- No description available.
has_value: gboolean (* has_value) ( GeglMetadataStore* self, const gchar* name )- No description available.
register_hook: void (* register_hook) ( GeglMetadataStore* self, const gchar* file_module_name, guint flags )- No description available.
parse_value: gboolean (* parse_value) ( GeglMetadataStore* self, GParamSpec* pspec, GValueTransform transform, const GValue* value )- No description available.
generate_value: gboolean (* generate_value) ( GeglMetadataStore* self, GParamSpec* pspec, GValueTransform transform, GValue* value )- No description available.
Virtual methods
Gegl.MetadataStoreClass.has_value
Test whether the GeglMetadataStore contains a value for the specified name.
Gegl.MetadataStoreClass.set_value
Set the specified metadata value. If value is NULL the default value from
the associated GParamSpec is used. This operation will fail if the value
has not been previously declared. A changed::name signal is emitted when
the value is set. If the value is shadowed by a property a notify::name
signal is also emitted.