Miscellaneous comment; conversion from GIF comment.
Copyright notice.
Description of image (possibly long).
Legal disclaimer.
Current file loader/saver module name. Valid only while a #GeglMetadata mapping is registered. This property is mainly provided for use in signal handlers.
A #GeglResolutionUnit specifying units for the image resolution (density).
X resolution or density in dots per unit.
Y resolution or density in dots per unit.
Software used to create the image.
Device used to create the image.
Time of original image creation.
Short (one line) title or caption for image.
Warning of nature of content.
Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
Declare a metadata value using a #GParamSpec.
A #GParamSpec
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Get name of image creator.
Get the comment.
Get the copyright notice.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Get description of image.
Get the legal disclaimer.
Return the name registered by the current file module.
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
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.
#GeglResolutionUnit return location
X resolution return location
Y resolution return location
Get the units used for resolution.
Get the X resolution or density in dots per unit.
Get the Y resolution or density in dots per unit.
Get software used to create the image.
Get device used to create the image.
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().
Metadata name
Get title or caption for image.
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.
Metadata name
An initialised #GValue.
Get warning.
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Test whether the #GeglMetadataStore contains a value for the specified name.
Metadata name
Checks whether object has a [floating][floating-ref] reference.
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.
#GeglMetadataIter referencing the value to get
Value to set in the interface
Initialise an iterator to find all supported metadata keys.
#GeglMetadataIter to be initialised
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().
#GeglMetadataIter to be initialised
Name of the value look up
Move the iterator to the next metadata item
#GeglMetadataIter to be updated
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.
#GeglMetadataIter referencing the value to set
Value to set in the interface
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.
The #GParamSpec used to declare the variable.
The metadata variable shadows a property.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
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.
String identifying the file module, e.g, "gegl:png-save"
Flags specifying capabilities of underlying file format
Array of mappings from file module metadata names to Gegl well-known names.
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Set name of image creator.
Artist string
Set the miscellaneous comment; conversion from GIF comment.
Comment string
Set the copyright notice.
Copyright string
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Set description of image.
Description string
Set the legal disclaimer.
Disclaimer string
Sets a property on an object.
the name of the property to set
the value
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.
Specify #GeglResolutionUnit
X resolution
Y resolution
Set the units used for the resolution (density) values.
Units as a #GeglResolutionUnit
Set the X resolution or density in dots per unit.
X resolution or density
Set the Y resolution or density in dots per unit.
Y resolution or density
Set software used to create the image.
Software string
Set device used to create the image.
Source 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().
Metadata name
String value to set
Set title or caption for image.
Title string
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.
Metadata name
(nullable): A valid #GValue or %NULL
Set the warning of nature of content.
Warning string
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Get the declared type of the value in the #GeglMetadataStore.
Metadata name
Decreases the reference count of object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
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.
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.
#GeglResolutionUnit return location
X resolution return location
Y resolution return location
Test whether the #GeglMetadataStore contains a value for the specified name.
Metadata name
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.
#GeglMetadataIter referencing the value to get
Value to set in the interface
Initialise an iterator to find all supported metadata keys.
#GeglMetadataIter to be initialised
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().
#GeglMetadataIter to be initialised
Name of the value look up
Move the iterator to the next metadata item
#GeglMetadataIter to be updated
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.
#GeglMetadataIter referencing the value to set
Value to set in the interface
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
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.
String identifying the file module, e.g, "gegl:png-save"
Flags specifying capabilities of underlying file format
Array of mappings from file module metadata names to Gegl well-known names.
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.
Specify #GeglResolutionUnit
X resolution
Y resolution
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.
Metadata name
(nullable): A valid #GValue or %NULL
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
Name of image creator.