Gtk.Constraint¶

Subclasses:: None

Methods¶

Inherited:: GObject.Object (37)
Structs:: GObject.ObjectClass (5)

class	`new` (target, target_attribute, relation, source, source_attribute, multiplier, constant, strength)
class	`new_constant` (target, target_attribute, relation, constant, strength)
	`get_constant` ()
	`get_multiplier` ()
	`get_relation` ()
	`get_source` ()
	`get_source_attribute` ()
	`get_strength` ()
	`get_target` ()
	`get_target_attribute` ()
	`is_attached` ()
	`is_constant` ()
	`is_required` ()

Virtual Methods¶

Inherited:: GObject.Object (7)

Properties¶

Name	Type	Flags
`constant`	`float`	r/w/co
`multiplier`	`float`	r/w/co
`relation`	`Gtk.ConstraintRelation`	r/w/co
`source`	`Gtk.ConstraintTarget`	r/w/co
`source-attribute`	`Gtk.ConstraintAttribute`	r/w/co
`strength`	`int`	r/w/co
`target`	`Gtk.ConstraintTarget`	r/w/co
`target-attribute`	`Gtk.ConstraintAttribute`	r/w/co

Signals¶

Inherited:: GObject.Object (1)

Fields¶

Inherited:: GObject.Object (1)

Class Details¶

class Gtk.Constraint(**kwargs)¶

Bases:: GObject.Object
Abstract:: No
Structure:: Gtk.ConstraintClass

GtkConstraint describes a constraint between attributes of two widgets, expressed as a linear equation.

The typical equation for a constraint is:

``: target.target_attr = source.source_attr × multiplier + constant

``

Each GtkConstraint is part of a system that will be solved by a [class`Gtk`.ConstraintLayout] in order to allocate and position each child widget or guide.

The source and target, as well as their attributes, of a GtkConstraint instance are immutable after creation.

classmethod new(target, target_attribute, relation, source, source_attribute, multiplier, constant, strength)[source]¶

Parameters:

target (Gtk.ConstraintTarget or None) – the target of the constraint
target_attribute (Gtk.ConstraintAttribute) – the attribute of target to be set
relation (Gtk.ConstraintRelation) – the relation equivalence between target_attribute and source_attribute
source (Gtk.ConstraintTarget or None) – the source of the constraint
source_attribute (Gtk.ConstraintAttribute) – the attribute of source to be read
multiplier (float) – a multiplication factor to be applied to source_attribute
constant (float) – a constant factor to be added to source_attribute
strength (int) – the strength of the constraint

Returns:

the newly created constraint

Return type:

Gtk.Constraint

Creates a new constraint representing a relation between a layout attribute on a source and a layout attribute on a target.

classmethod new_constant(target, target_attribute, relation, constant, strength)[source]¶

Parameters:

target (Gtk.ConstraintTarget or None) – a the target of the constraint
target_attribute (Gtk.ConstraintAttribute) – the attribute of target to be set
relation (Gtk.ConstraintRelation) – the relation equivalence between target_attribute and constant
constant (float) – a constant factor to be set on target_attribute
strength (int) – the strength of the constraint

Returns:

the newly created constraint

Return type:

Gtk.Constraint

Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

get_constant()[source]¶

Returns:: a constant factor
Return type:: float

Retrieves the constant factor added to the source attributes’ value.

get_multiplier()[source]¶

Returns:: a multiplication factor
Return type:: float

Retrieves the multiplication factor applied to the source attribute’s value.

get_relation()[source]¶

Returns:: a relation type
Return type:: Gtk.ConstraintRelation

The order relation between the terms of the constraint.

get_source()[source]¶

Returns:: the source of the constraint
Return type:: Gtk.ConstraintTarget or None

Retrieves the [iface`Gtk`.ConstraintTarget] used as the source for the constraint.

If the source is set to NULL at creation, the constraint will use the widget using the [class`Gtk`.ConstraintLayout] as the source.

get_source_attribute()[source]¶

Returns:: the source’s attribute
Return type:: Gtk.ConstraintAttribute

Retrieves the attribute of the source to be read by the constraint.

get_strength()[source]¶

Returns:: the strength value
Return type:: int

Retrieves the strength of the constraint.

get_target()[source]¶

Returns:: a GtkConstraintTarget
Return type:: Gtk.ConstraintTarget or None

Retrieves the [iface`Gtk`.ConstraintTarget] used as the target for the constraint.

If the targe is set to NULL at creation, the constraint will use the widget using the [class`Gtk`.ConstraintLayout] as the target.

get_target_attribute()[source]¶

Returns:: the target’s attribute
Return type:: Gtk.ConstraintAttribute

Retrieves the attribute of the target to be set by the constraint.

is_attached()[source]¶

Returns:: TRUE if the constraint is attached
Return type:: bool

Checks whether the constraint is attached to a [class`Gtk`.ConstraintLayout], and it is contributing to the layout.

is_constant()[source]¶

Returns:: TRUE if the constraint is a constant relation
Return type:: bool

Checks whether the constraint describes a relation between an attribute on the [property`Gtk`.Constraint:target] and a constant value.

is_required()[source]¶

Returns:: True if the constraint is required
Return type:: bool

Checks whether the constraint is a required relation for solving the constraint layout.

Property Details¶

Gtk.Constraint.props.constant¶

Name:: constant
Type:: float
Default Value:: 0.0
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The constant value to be added to the [property`Gtk`.Constraint:source-attribute].

Gtk.Constraint.props.multiplier¶

Name:: multiplier
Type:: float
Default Value:: 1.0
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The multiplication factor to be applied to the [property`Gtk`.Constraint:source-attribute].

Gtk.Constraint.props.relation¶

Name:: relation
Type:: Gtk.ConstraintRelation
Default Value:: Gtk.ConstraintRelation.EQ
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The order relation between the terms of the constraint.

Gtk.Constraint.props.source¶

Name:: source
Type:: Gtk.ConstraintTarget
Default Value:: None
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The source of the constraint.

The constraint will set the [property`Gtk`.Constraint:target-attribute] property of the target using the [property`Gtk`.Constraint:source-attribute] property of the source.

Gtk.Constraint.props.source_attribute¶

Name:: source-attribute
Type:: Gtk.ConstraintAttribute
Default Value:: Gtk.ConstraintAttribute.NONE
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The attribute of the [property`Gtk`.Constraint:source] read by the constraint.

Gtk.Constraint.props.strength¶

Name:: strength
Type:: int
Default Value:: 1001001000
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The strength of the constraint.

The strength can be expressed either using one of the symbolic values of the [enum`Gtk`.ConstraintStrength] enumeration, or any positive integer value.

Gtk.Constraint.props.target¶

Name:: target
Type:: Gtk.ConstraintTarget
Default Value:: None
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The target of the constraint.

The constraint will set the [property`Gtk`.Constraint:target-attribute] property of the target using the [property`Gtk`.Constraint:source-attribute] property of the source widget.

Gtk.Constraint.props.target_attribute¶

Name:: target-attribute
Type:: Gtk.ConstraintAttribute
Default Value:: Gtk.ConstraintAttribute.NONE
Flags:: READABLE, WRITABLE, CONSTRUCT_ONLY

The attribute of the [property`Gtk`.Constraint:target] set by the constraint.