cola::SeparationConstraint Class Reference

A separation constraint specifies a simple horizontal or vertical spacing constraint between 2 nodes or alignment constraints. More...

#include <compound_constraints.h>

Inheritance diagram for cola::SeparationConstraint:

Collaboration diagram for cola::SeparationConstraint:

Public Member Functions
	SeparationConstraint (const vpsc::Dim dim, unsigned l, unsigned r, double g, bool equality=false)
	Constructs a new SeparationConstraint between two nodes in the specified dimension. More...
	SeparationConstraint (const vpsc::Dim dim, AlignmentConstraint *l, AlignmentConstraint *r, double g, bool equality=false)
	Constructs a new SeparationConstraint between two alignment constraints in the specified dimension. More...
std::string	toString (void) const
	Returns a textual description of the compound constraint. More...
void	generateVariables (const vpsc::Dim dim, vpsc::Variables &vars)
	Implemented by the compound constraint to generate any additional required variables in the given dimension. More...
void	generateSeparationConstraints (const vpsc::Dim dim, vpsc::Variables &vs, vpsc::Constraints &cs, vpsc::Rectangles &bbs)
	Implemented by the compound constraint to generate the low-level separation constraints in the given dimension. More...
Public Member Functions inherited from cola::CompoundConstraint
virtual void	updatePosition (const vpsc::Dim dim)
	Implemented by the compound constraint to send position information back to the interface. More...

Detailed Description

A separation constraint specifies a simple horizontal or vertical spacing constraint between 2 nodes or alignment constraints.

The non-equality constraint is lPos + g <= rPos and the equality constraint is lPos + g = rPos

Note

With an equality, you can effectively reverse the ordering of the two variables by making the gap a negative number. This is not so for the non-equality case, there you need to keep the same gap value but reverse the order of the variables passed to the constructor.

Constructor & Destructor Documentation

SeparationConstraint() [1/2]

cola::SeparationConstraint::SeparationConstraint	(	const vpsc::Dim	dim,
		unsigned	l,
		unsigned	r,
		double	g,
		bool	equality = false
	)

Constructs a new SeparationConstraint between two nodes in the specified dimension.

The constraint will keep the centre of the left node to the left of the right node by exactly or more than the specified gap.

Parameters

[in]	dim	The dimension the constraint will operate in.
[in]	l	The index of the left node.
[in]	r	The index of the right node.
[in]	g	The minimum or exact distance to separate the two nodes.
[in]	equality	Whether or not the constraint is an exact distance.

SeparationConstraint() [2/2]

cola::SeparationConstraint::SeparationConstraint	(	const vpsc::Dim	dim,
		AlignmentConstraint *	l,
		AlignmentConstraint *	r,
		double	g,
		bool	equality = false
	)

Constructs a new SeparationConstraint between two alignment constraints in the specified dimension.

The constraint will keep the centre of the left alignment line to the left of the right alignment line by exactly or more than the specified gap.

Parameters

[in]	dim	The dimension the constraint will operate in.
[in]	l	A pointer to the left AlignmentConstraint.
[in]	r	A pointer to the right AlignmentConstraint.
[in]	g	The minimum or exact distance to separate the two alignment constraints.
[in]	equality	Whether or not the constraint is an exact distance.

Member Function Documentation

generateSeparationConstraints()

void cola::SeparationConstraint::generateSeparationConstraints ( const vpsc::Dim  dim, vpsc::Variables &  var, vpsc::Constraints &  cs, vpsc::Rectangles &  bbs  )

virtual

Implemented by the compound constraint to generate the low-level separation constraints in the given dimension.

These constraints will be added to the list of constraints cs.

Parameters

[in]	dim	The current active dimension.
[in]	vars	The list of variables for the overall problem instance.
[in,out]	cs	The list of constraints to which the generated constraints will be added.
[in]	bbs	The list of bounding boxes for all rectangles in the current problem. It has the same order as vars.

Implements cola::CompoundConstraint.

generateVariables()

void cola::SeparationConstraint::generateVariables ( const vpsc::Dim  dim, vpsc::Variables &  vars  )

virtual

Implemented by the compound constraint to generate any additional required variables in the given dimension.

Generate any additional variables required by this compound constraint when operating in the given dimension dim and add them to vars. These variables should be cleaned up by the caller after the VPSC problem is solved.

The variables' ideal position and weight should be set by the compound constraint and they should be added to the end of vars.

Parameters

[in]	dim	The current active dimension.
[in,out]	vars	The list of variables for the overall problem instance to which any variables generated should be appended.

Implements cola::CompoundConstraint.

toString()

std::string cola::SeparationConstraint::toString ( void  ) const

virtual

Returns a textual description of the compound constraint.

Returns

A string describing the compound constraint.

Implements cola::CompoundConstraint.

---

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

• libcola/compound_constraints.h
• libcola/compound_constraints.cpp