API reference - Class LayoutMetaInfo

Notation used in Ruby API documentation

Module: db

Description: A piece of layout meta information

Layout meta information is basically additional data that can be attached to a layout. Layout readers may generate meta information and some writers will add layout information to the layout object. Some writers will also read meta information to determine certain attributes.

Multiple layout meta information objects can be attached to one layout using Layout#add_meta_info. Meta information is identified by a unique name and carries a string value plus an optional description string. The description string is for information only and is not evaluated by code.

Meta information can be attached to the layout object and to cells. It is similar to user properties. The differences are:

Elementary (serializable) objects are: Box, DBox, Edge, DEdge, EdgePair, DEdgePair, EdgePairs, Edges, LayerProperties, Matrix2d, Matrix3d, Path, DPath, Point, DPoint, Polygon, DPolygon, SimplePolygon, DSimplePolygon, Region, Text, DText, Texts, Trans, DTrans, CplxTrans, ICplxTrans, DCplxTrans, VCplxTrans, Vector, DVector (list may not be complete).

KLayout itself also generates meta information with specific keys. For disambiguation, namespaces can be established by prefixing the key strings with some unique identifier in XML fashion, like a domain name - e.g. 'example.com:key'.

Note: only meta information marked with is_persisted? == true is stored in GDS or OASIS files. This is not the default setting, so you need to explicitly set that flag.

See also Layout#each_meta_info, Layout#meta_info_value, Layout#meta_info and Layout#remove_meta_info as well as the corresponding Cell methods.

An example of how to attach persisted meta information to a cell is here:

ly = RBA::Layout::new
c1 = ly.create_cell("C1")

mi = RBA::LayoutMetaInfo::new("the-answer", 42.0)
mi.persisted = true
c1.add_meta_info(mi)

# will now hold this piece of meta information attached to cell 'C1':
ly.write("to.gds")

This class has been introduced in version 0.25 and was extended in version 0.28.8.

Public constructors

new LayoutMetaInfo ptrnew(string name,
variant value,
string description = ,
bool persisted = false)
Creates a layout meta info object

Public methods

[const]LayoutMetaInfo ptr_const_castReturns a non-const reference to self.
void_createEnsures the C++ object is created
void_destroyExplicitly destroys the object
[const]bool_destroyed?Returns a value indicating whether the object was already destroyed
[const]bool_is_const_object?Returns a value indicating whether the reference is a const reference
void_manageMarks the object as managed by the script side.
void_unmanageMarks the object as no longer owned by the script side.
voidassign(const LayoutMetaInfo other)Assigns another object to self
[const]stringdescriptionGets the description of the layout meta info object
voiddescription=(string description)Sets the description of the layout meta info object
[const]new LayoutMetaInfo ptrdupCreates a copy of self
[const]boolis_persisted?Gets a value indicating whether the meta information will be persisted
[const]stringnameGets the name of the layout meta info object
voidname=(string name)Sets the name of the layout meta info object
voidpersisted=(bool flag)Sets a value indicating whether the meta information will be persisted
[const]variantvalueGets the value of the layout meta info object
voidvalue=(variant value)Sets the value of the layout meta info object

Deprecated methods (protected, public, static, non-static and constructors)

voidcreateUse of this method is deprecated. Use _create instead
voiddestroyUse of this method is deprecated. Use _destroy instead
[const]booldestroyed?Use of this method is deprecated. Use _destroyed? instead
[const]boolis_const_object?Use of this method is deprecated. Use _is_const_object? instead

Detailed description

_const_cast

Signature: [const] LayoutMetaInfo ptr _const_cast

Description: Returns a non-const reference to self.

Basically, this method allows turning a const object reference to a non-const one. This method is provided as last resort to remove the constness from an object. Usually there is a good reason for a const object reference, so using this method may have undesired side effects.

This method has been introduced in version 0.29.6.

_create

Signature: void _create

Description: Ensures the C++ object is created

Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created.

_destroy

Signature: void _destroy

Description: Explicitly destroys the object

Explicitly destroys the object on C++ side if it was owned by the script interpreter. Subsequent access to this object will throw an exception. If the object is not owned by the script, this method will do nothing.

_destroyed?

Signature: [const] bool _destroyed?

Description: Returns a value indicating whether the object was already destroyed

This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself.

_is_const_object?

Signature: [const] bool _is_const_object?

Description: Returns a value indicating whether the reference is a const reference

This method returns true, if self is a const reference. In that case, only const methods may be called on self.

_manage

Signature: void _manage

Description: Marks the object as managed by the script side.

After calling this method on an object, the script side will be responsible for the management of the object. This method may be called if an object is returned from a C++ function and the object is known not to be owned by any C++ instance. If necessary, the script side may delete the object if the script's reference is no longer required.

Usually it's not required to call this method. It has been introduced in version 0.24.

_unmanage

Signature: void _unmanage

Description: Marks the object as no longer owned by the script side.

Calling this method will make this object no longer owned by the script's memory management. Instead, the object must be managed in some other way. Usually this method may be called if it is known that some C++ object holds and manages this object. Technically speaking, this method will turn the script's reference into a weak reference. After the script engine decides to delete the reference, the object itself will still exist. If the object is not managed otherwise, memory leaks will occur.

Usually it's not required to call this method. It has been introduced in version 0.24.

assign

Signature: void assign (const LayoutMetaInfo other)

Description: Assigns another object to self

create

Signature: void create

Description: Ensures the C++ object is created

Use of this method is deprecated. Use _create instead

Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created.

description

Signature: [const] string description

Description: Gets the description of the layout meta info object

Python specific notes:
The object exposes a readable attribute 'description'. This is the getter.

description=

Signature: void description= (string description)

Description: Sets the description of the layout meta info object

Python specific notes:
The object exposes a writable attribute 'description'. This is the setter.

destroy

Signature: void destroy

Description: Explicitly destroys the object

Use of this method is deprecated. Use _destroy instead

Explicitly destroys the object on C++ side if it was owned by the script interpreter. Subsequent access to this object will throw an exception. If the object is not owned by the script, this method will do nothing.

destroyed?

Signature: [const] bool destroyed?

Description: Returns a value indicating whether the object was already destroyed

Use of this method is deprecated. Use _destroyed? instead

This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself.

dup

Signature: [const] new LayoutMetaInfo ptr dup

Description: Creates a copy of self

Python specific notes:
This method also implements '__copy__' and '__deepcopy__'.

is_const_object?

Signature: [const] bool is_const_object?

Description: Returns a value indicating whether the reference is a const reference

Use of this method is deprecated. Use _is_const_object? instead

This method returns true, if self is a const reference. In that case, only const methods may be called on self.

is_persisted?

Signature: [const] bool is_persisted?

Description: Gets a value indicating whether the meta information will be persisted

This predicate was introduced in version 0.28.8.

Python specific notes:
The object exposes a readable attribute 'persisted'. This is the getter.

name

Signature: [const] string name

Description: Gets the name of the layout meta info object

Python specific notes:
The object exposes a readable attribute 'name'. This is the getter.

name=

Signature: void name= (string name)

Description: Sets the name of the layout meta info object

Python specific notes:
The object exposes a writable attribute 'name'. This is the setter.

new

Signature: [static] new LayoutMetaInfo ptr new (string name, variant value, string description = , bool persisted = false)

Description: Creates a layout meta info object

name:The name
value:The value
description:An optional description text
persisted:If true, the meta information will be persisted in some file formats, like GDS2

The 'persisted' attribute has been introduced in version 0.28.8.

Python specific notes:
This method is the default initializer of the object.

persisted=

Signature: void persisted= (bool flag)

Description: Sets a value indicating whether the meta information will be persisted

This predicate was introduced in version 0.28.8.

Python specific notes:
The object exposes a writable attribute 'persisted'. This is the setter.

value

Signature: [const] variant value

Description: Gets the value of the layout meta info object

Python specific notes:
The object exposes a readable attribute 'value'. This is the getter.

value=

Signature: void value= (variant value)

Description: Sets the value of the layout meta info object

Python specific notes:
The object exposes a writable attribute 'value'. This is the setter.