aqt::cassowary::Constraint Class Reference

A linear constraint. More...

#include <aqt/cassowary/Constraint.hpp>

Inheritance diagram for aqt::cassowary::Constraint:

Public Member Functions
	Constraint (QQuickItem *pParent=nullptr)
Q_SIGNAL void	exprChanged (QVariant expr)
Q_INVOKABLE QVariant	plus (QVariant, QVariant)
	Returns an arithmetic expression representing the sum of its arguments, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	plus (QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	plus (QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	plus (QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	plus (QVariant, QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	minus (QVariant, QVariant)
	Returns an arithmetic expression representing the substraction of its arguments, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	minus (QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	minus (QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	minus (QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	minus (QVariant, QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	times (QVariant, QVariant)
	Returns an arithmetic expression representing the product of its arguments, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	times (QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	times (QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	times (QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	times (QVariant, QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	divide (QVariant, QVariant)
	Returns an arithmetic expression representing the division of its arguments, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	divide (QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	divide (QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	divide (QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	divide (QVariant, QVariant, QVariant, QVariant, QVariant, QVariant)
Q_INVOKABLE QVariant	eq (QVariant a, QVariant b)
	Returns a comparison expression stating the equality of its arguments, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	geq (QVariant a, QVariant b)
	Returns a comparison expression stating that its first argument should be less than the later, or undefined if any of its arguments is undefined. More...
Q_INVOKABLE QVariant	leq (QVariant a, QVariant b)
	Returns a comparison expression stating that its first argument should be greater than the later, or undefined if any of its arguments is undefined. More...
Public Member Functions inherited from aqt::cassowary::ConstraintBase
	ConstraintBase (QQuickItem *pParent=nullptr, Strength::Types strength=Strength::Required, double weight=1.0)
Q_SIGNAL void	strengthChanged (aqt::cassowary::Strength::Types strength)
Q_SIGNAL void	weightChanged (double weight)
Q_SIGNAL void	whenChanged (bool when)
Public Member Functions inherited from aqt::cassowary::Contextual
	Contextual (QQuickItem *pParent=nullptr)
std::shared_ptr< Context >	context ()
std::shared_ptr< const Context >	context () const
Q_SIGNAL void	contextChanged ()
Q_SIGNAL void	extendChanged (aqt::cassowary::Contextual *extend)
Q_INVOKABLE void	commit ()
	Applies all the changes associated to the context used by this contextual. More...
Q_INVOKABLE void	defer (QJSValue cb)
	Executes the callback cb at the end of the next phase of updates in the solver, but before the changes are propagated to the bindings.
void	defer (Context::Callback cb)
void	defer_ (Context::Callback cb)
template<typename... Args>
void	log (Args &&...args)
	Used to log a debug trace, that may be visible when the current context's debug property is set. More...

Properties
QVariant	expr
	Expression that determines the linear constraint. More...
Properties inherited from aqt::cassowary::ConstraintBase
aqt::cassowary::Strength::Types	strength
	Sets the strength of a constraint. More...
double	weight
	Sets the weight of a constraint. More...
bool	when
	The constraint is enabled when this property holds a true value, otherwise it has no effect.
Properties inherited from aqt::cassowary::Contextual
aqt::cassowary::Contextual	extend
	If non-null, this contextual will use the same context as used by this contextual.

Additional Inherited Members
Protected Member Functions inherited from aqt::cassowary::ConstraintBase
bool	when () const
const rhea::constraint &	get () const
void	set (std::shared_ptr< rhea::abstract_constraint > constraint)
void	addIn (Context &ctx) override
void	removeIn (Context &ctx) override
Protected Member Functions inherited from aqt::cassowary::Contextual
void	add ()
void	remove ()
template<typename Fn >
void	update (Fn &&cb)
template<typename Fn >
Context::Callback	guarded (Fn fn)
void	updateContext ()
Contextual *	provider ()
virtual std::shared_ptr< Context >	provided ()

Detailed Description

A linear constraint.

A linear constraint allows us to set equations or inequalities that relate variables in the system. The solver will log errors in the presence of non-linear constraints or conflicting constraints with Required strength.

Example

Solver {
    Variable { id: vX }
    Variable { id: vY }
    Constraint {
        expr: eq(vX, times(2, vY))
    }
    Constraint {
        expr: geq(plus(vX, vY), 42)
        when: root.height > 100
    }
    // Error, non-linear expression
    Constraint { expr: geq(times(vX, vX), vY) }
}

Import in QML

import Aqt.Cassowary 1.0

Since

1.0

See also

ConstraintBase

Strength

Member Function Documentation

Q_INVOKABLE QVariant aqt::cassowary::Constraint::divide	(	QVariant	,
		QVariant
	)

Returns an arithmetic expression representing the division of its arguments, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::eq	(	QVariant	a,
		QVariant	b
	)

Returns a comparison expression stating the equality of its arguments, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::geq	(	QVariant	a,
		QVariant	b
	)

Returns a comparison expression stating that its first argument should be less than the later, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::leq	(	QVariant	a,
		QVariant	b
	)

Returns a comparison expression stating that its first argument should be greater than the later, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::minus	(	QVariant	,
		QVariant
	)

Returns an arithmetic expression representing the substraction of its arguments, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::plus	(	QVariant	,
		QVariant
	)

Returns an arithmetic expression representing the sum of its arguments, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Q_INVOKABLE QVariant aqt::cassowary::Constraint::times	(	QVariant	,
		QVariant
	)

Returns an arithmetic expression representing the product of its arguments, or undefined if any of its arguments is undefined.

Its arguments may be arithmetic expressions, Variable objects or numbers.

Property Documentation

QVariant aqt::cassowary::Constraint::expr

Expression that determines the linear constraint.

It can hold a comparison expression or undefined. If undefined, the constraint will have no effect.

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The documentation for this class was generated from the following file:

• src/aqt/cassowary/Constraint.hpp