Gegl.Metadata¶

Implementations:: Gegl.MetadataStore

Methods¶

	`get_resolution` (unit, x, y)
	`iter_get_value` (iter, value)
	`iter_init` (iter)
	`iter_lookup` (iter, key)
	`iter_next` (iter)
	`iter_set_value` (iter, value)
	`register_map` (file_module, flags, map)
	`set_resolution` (unit, x, y)
	`unregister_map` ()

Virtual Methods¶

	`do_get_resolution` (unit, x, y)
	`do_iter_get_value` (iter, value)
	`do_iter_init` (iter)
	`do_iter_lookup` (iter, key)
	`do_iter_next` (iter)
	`do_iter_set_value` (iter, value)
	`do_register_map` (file_module, flags, map)
	`do_set_resolution` (unit, x, y)

Properties¶

None

Signals¶

None

Fields¶

None

Class Details¶

class Gegl.Metadata¶

Bases:: GObject.GInterface
Structure:: Gegl.MetadataInterface

get_resolution(unit, x, y)¶

Parameters:

unit (Gegl.ResolutionUnit) – Gegl.ResolutionUnit return location
x (float) – X resolution return location
y (float) – Y resolution return location

Returns:

True if successful.

Return type:

bool

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.

iter_get_value(iter, value)¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter referencing the value to get
value (GObject.Value) – Value to set in the interface

Returns:

True if successful.

Return type:

bool

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.

iter_init(iter)¶

Parameters:: iter (Gegl.MetadataIter) – Gegl.MetadataIter to be initialised

Initialise an iterator to find all supported metadata keys.

iter_lookup(iter, key)¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter to be initialised
key (str) – Name of the value look up

Returns:

True if key is found.

Return type:

bool

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().

iter_next(iter)¶

Parameters:: iter (Gegl.MetadataIter) – Gegl.MetadataIter to be updated
Returns:: key name if found, else None
Return type:: str

Move the iterator to the next metadata item

iter_set_value(iter, value)¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter referencing the value to set
value (GObject.Value) – Value to set in the interface

Returns:

True if successful.

Return type:

bool

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.

register_map(file_module, flags, map)¶

Parameters:

file_module (str) – String identifying the file module, e.g, "gegl:png-save"
flags (int) – Flags specifying capabilities of underlying file format
map ([Gegl.MetadataMap]) – Array of mappings from file module metadata names to Gegl well-known names.

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 GObject.Value transformation function may be supplied, e.g. to parse or format timestamps.

set_resolution(unit, x, y)¶

Parameters:

unit (Gegl.ResolutionUnit) – Specify Gegl.ResolutionUnit
x (float) – X resolution
y (float) – Y resolution

Returns:

True if successful.

Return type:

bool

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.

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.

do_get_resolution(unit, x, y) virtual¶

Parameters:

unit (Gegl.ResolutionUnit) – Gegl.ResolutionUnit return location
x (float) – X resolution return location
y (float) – Y resolution return location

Returns:

True if successful.

Return type:

bool

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.

do_iter_get_value(iter, value) virtual¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter referencing the value to get
value (GObject.Value) – Value to set in the interface

Returns:

True if successful.

Return type:

bool

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.

do_iter_init(iter) virtual¶

Parameters:: iter (Gegl.MetadataIter) – Gegl.MetadataIter to be initialised

Initialise an iterator to find all supported metadata keys.

do_iter_lookup(iter, key) virtual¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter to be initialised
key (str) – Name of the value look up

Returns:

True if key is found.

Return type:

bool

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().

do_iter_next(iter) virtual¶

Parameters:: iter (Gegl.MetadataIter) – Gegl.MetadataIter to be updated
Returns:: key name if found, else None
Return type:: str

Move the iterator to the next metadata item

do_iter_set_value(iter, value) virtual¶

Parameters:

iter (Gegl.MetadataIter) – Gegl.MetadataIter referencing the value to set
value (GObject.Value) – Value to set in the interface

Returns:

True if successful.

Return type:

bool

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.

do_register_map(file_module, flags, map) virtual¶

Parameters:

file_module (str) – String identifying the file module, e.g, "gegl:png-save"
flags (int) – Flags specifying capabilities of underlying file format
map ([Gegl.MetadataMap]) – Array of mappings from file module metadata names to Gegl well-known names.

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 GObject.Value transformation function may be supplied, e.g. to parse or format timestamps.

do_set_resolution(unit, x, y) virtual¶

Parameters:

unit (Gegl.ResolutionUnit) – Specify Gegl.ResolutionUnit
x (float) – X resolution
y (float) – Y resolution

Returns:

True if successful.

Return type:

bool

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.