Geom2d_Transformation Class Reference

The class Transformation allows to create Translation, Rotation, Symmetry, Scaling and complex transformations obtained by combination of the previous elementary transformations. The Transformation class can also be used to construct complex transformations by combining these elementary transformations. However, these transformations can never change the type of an object. For example, the projection transformation can change a circle into an ellipse, and therefore change the real type of the object. Such a transformation is forbidden in this environment and cannot be a Geom2d_Transformation. The transformation can be represented as follows: More...

#include <Geom2d_Transformation.hxx>

Inheritance diagram for Geom2d_Transformation:

Public Member Functions
	Geom2d_Transformation ()
	Creates an identity transformation.
	Geom2d_Transformation (const gp_Trsf2d &T)
	Creates a persistent copy of T.
void	SetMirror (const gp_Pnt2d &P)
	Makes the transformation into a symmetrical transformation with respect to a point P. P is the center of the symmetry.
void	SetMirror (const gp_Ax2d &A)
	Makes the transformation into a symmetrical transformation with respect to an axis A. A is the center of the axial symmetry.
void	SetRotation (const gp_Pnt2d &P, const double Ang)
	Assigns to this transformation the geometric properties of a rotation at angle Ang (in radians) about point P.
void	SetScale (const gp_Pnt2d &P, const double S)
	Makes the transformation into a scale. P is the center of the scale and S is the scaling value.
void	SetTransformation (const gp_Ax2d &FromSystem1, const gp_Ax2d &ToSystem2)
	Makes a transformation allowing passage from the coordinate system "FromSystem1" to the coordinate system "ToSystem2".
void	SetTransformation (const gp_Ax2d &ToSystem)
	Makes the transformation allowing passage from the basic coordinate system {P(0.,0.,0.), VX (1.,0.,0.), VY (0.,1.,0.)} to the local coordinate system defined with the Ax2d ToSystem.
void	SetTranslation (const gp_Vec2d &V)
	Makes the transformation into a translation. V is the vector of the translation.
void	SetTranslation (const gp_Pnt2d &P1, const gp_Pnt2d &P2)
	Makes the transformation into a translation from the point P1 to the point P2.
void	SetTrsf2d (const gp_Trsf2d &T)
	Makes the transformation into a transformation T from package gp.
bool	IsNegative () const
	Checks whether this transformation is an indirect transformation: returns true if the determinant of the matrix of the vectorial part of the transformation is less than 0.
gp_TrsfForm	Form () const
	Returns the nature of this transformation as a value of the gp_TrsfForm enumeration. Returns the nature of the transformation. It can be Identity, Rotation, Translation, PntMirror, Ax1Mirror, Scale, CompoundTrsf.
double	ScaleFactor () const
	Returns the scale value of the transformation.
gp_Trsf2d	Trsf2d () const
	Converts this transformation into a gp_Trsf2d transformation. Returns a non persistent copy of <me>. -C++: return const&.
double	Value (const int Row, const int Col) const
	Returns the coefficients of the global matrix of transformation. It is a 2 rows X 3 columns matrix.
void	Invert ()
	Computes the inverse of this transformation and assigns the result to this transformation.
occ::handle< Geom2d_Transformation >	Inverted () const
	Computes the inverse of this transformation and creates a new one. Raises ConstructionError if the transformation is singular. This means that the ScaleFactor is lower or equal to Resolution from package gp.
occ::handle< Geom2d_Transformation >	Multiplied (const occ::handle< Geom2d_Transformation > &Other) const
	Computes the transformation composed with Other and <me>. <me> * Other. Returns a new transformation.
occ::handle< Geom2d_Transformation >	operator* (const occ::handle< Geom2d_Transformation > &Other) const
void	Multiply (const occ::handle< Geom2d_Transformation > &Other)
	Computes the transformation composed with Other and <me> . <me> = <me> * Other.
void	operator*= (const occ::handle< Geom2d_Transformation > &Other)
void	Power (const int N)
	Raised if N < 0 and if the transformation is not inversible.
occ::handle< Geom2d_Transformation >	Powered (const int N) const
	Raised if N < 0 and if the transformation is not inversible.
void	PreMultiply (const occ::handle< Geom2d_Transformation > &Other)
	Computes the matrix of the transformation composed with <me> and Other. <me> = Other * <me>.
void	Transforms (double &X, double &Y) const
	Applies the transformation <me> to the triplet {X, Y}.
occ::handle< Geom2d_Transformation >	Copy () const
	Creates a new object, which is a copy of this transformation.
Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor.
	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing.
Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter.
virtual	~Standard_Transient ()=default
	Destructor must be virtual.
virtual const opencascade::handle< Standard_Type > &	DynamicType () const
	Returns a type descriptor about this object.
bool	IsInstance (const opencascade::handle< Standard_Type > &theType) const
	Returns a true value if this is an instance of Type.
bool	IsInstance (const char *const theTypeName) const
	Returns a true value if this is an instance of TypeName.
bool	IsKind (const opencascade::handle< Standard_Type > &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
bool	IsKind (const char *const theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
Standard_Transient *	This () const
	Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.
int	GetRefCount () const noexcept
	Get the reference counter of this object.
void	IncrementRefCounter () noexcept
	Increments the reference counter of this object. Uses relaxed memory ordering since incrementing only requires atomicity, not synchronization with other memory operations.
int	DecrementRefCounter () noexcept
	Decrements the reference counter of this object; returns the decremented value. Uses release ordering for the decrement to ensure all writes to the object are visible before the count reaches zero. An acquire fence is added only when the count reaches zero, ensuring proper synchronization before deletion. This is more efficient than using acq_rel for every decrement.
virtual void	Delete () const
	Memory deallocator for transient classes.

Additional Inherited Members
typedef void	base_type
	Returns a type descriptor about this object.
static constexpr const char *	get_type_name ()
	Returns a type descriptor about this object.
static const opencascade::handle< Standard_Type > &	get_type_descriptor ()
	Returns type descriptor of Standard_Transient class.

Detailed Description

The class Transformation allows to create Translation, Rotation, Symmetry, Scaling and complex transformations obtained by combination of the previous elementary transformations. The Transformation class can also be used to construct complex transformations by combining these elementary transformations. However, these transformations can never change the type of an object. For example, the projection transformation can change a circle into an ellipse, and therefore change the real type of the object. Such a transformation is forbidden in this environment and cannot be a Geom2d_Transformation. The transformation can be represented as follows:

V1 V2 T | a11 a12 a14 | | x | | x'| | a21 a22 a24 | | y | | y'| | 0 0 1 | | 1 | | 1 |

where {V1, V2} defines the vectorial part of the transformation and T defines the translation part of the transformation.

• Geom2d_Transformation transformations provide the same kind of "geometric" services as gp_Trsf2d ones but have more complex data structures. The geometric objects provided by the Geom2d package use gp_Trsf2d transformations in the syntaxes Transform and Transformed.
• Geom2d_Transformation transformations are used in a context where they can be shared by several objects contained inside a common data structure.

Constructor & Destructor Documentation

Geom2d_Transformation() [1/2]

Geom2d_Transformation::Geom2d_Transformation

(

)

Creates an identity transformation.

Geom2d_Transformation() [2/2]

Geom2d_Transformation::Geom2d_Transformation

(

const gp_Trsf2d &

T

)

Creates a persistent copy of T.

Member Function Documentation

Copy()

occ::handle< Geom2d_Transformation > Geom2d_Transformation::Copy ( ) const

nodiscard

Creates a new object, which is a copy of this transformation.

Form()

gp_TrsfForm Geom2d_Transformation::Form

(

)

const

Returns the nature of this transformation as a value of the gp_TrsfForm enumeration. Returns the nature of the transformation. It can be Identity, Rotation, Translation, PntMirror, Ax1Mirror, Scale, CompoundTrsf.

Invert()

void Geom2d_Transformation::Invert

(

)

Computes the inverse of this transformation and assigns the result to this transformation.

Raised if the transformation is singular. This means that the ScaleFactor is lower or equal to Resolution from package gp.

Inverted()

occ::handle< Geom2d_Transformation > Geom2d_Transformation::Inverted ( ) const

nodiscard

Computes the inverse of this transformation and creates a new one. Raises ConstructionError if the transformation is singular. This means that the ScaleFactor is lower or equal to Resolution from package gp.

IsNegative()

bool Geom2d_Transformation::IsNegative

(

)

const

Checks whether this transformation is an indirect transformation: returns true if the determinant of the matrix of the vectorial part of the transformation is less than 0.

Multiplied()

occ::handle< Geom2d_Transformation > Geom2d_Transformation::Multiplied ( const occ::handle< Geom2d_Transformation > & Other ) const

nodiscard

Computes the transformation composed with Other and <me>. <me> * Other. Returns a new transformation.

Multiply()

void Geom2d_Transformation::Multiply

(

const occ::handle< Geom2d_Transformation > &

Other

)

Computes the transformation composed with Other and <me> . <me> = <me> * Other.

Computes the following composition of transformations if N > 0 <me> * <me> * .......* <me>. if N = 0 Identity if N < 0 <me>.Invert() * .........* <me>.Invert()

operator*()

occ::handle< Geom2d_Transformation > Geom2d_Transformation::operator* ( const occ::handle< Geom2d_Transformation > & Other ) const

inlinenodiscard

operator*=()

void Geom2d_Transformation::operator*= ( const occ::handle< Geom2d_Transformation > & Other )

inline

Power()

void Geom2d_Transformation::Power

(

const int

N

)

Raised if N < 0 and if the transformation is not inversible.

Powered()

occ::handle< Geom2d_Transformation > Geom2d_Transformation::Powered

(

const int

N

)

const

Raised if N < 0 and if the transformation is not inversible.

PreMultiply()

void Geom2d_Transformation::PreMultiply

(

const occ::handle< Geom2d_Transformation > &

Other

)

Computes the matrix of the transformation composed with <me> and Other. <me> = Other * <me>.

ScaleFactor()

double Geom2d_Transformation::ScaleFactor

(

)

const

Returns the scale value of the transformation.

SetMirror() [1/2]

void Geom2d_Transformation::SetMirror

(

const gp_Ax2d &

A

)

Makes the transformation into a symmetrical transformation with respect to an axis A. A is the center of the axial symmetry.

SetMirror() [2/2]

void Geom2d_Transformation::SetMirror

(

const gp_Pnt2d &

P

)

Makes the transformation into a symmetrical transformation with respect to a point P. P is the center of the symmetry.

SetRotation()

void Geom2d_Transformation::SetRotation	(	const gp_Pnt2d &	P,
		const double	Ang )

Assigns to this transformation the geometric properties of a rotation at angle Ang (in radians) about point P.

SetScale()

void Geom2d_Transformation::SetScale	(	const gp_Pnt2d &	P,
		const double	S )

Makes the transformation into a scale. P is the center of the scale and S is the scaling value.

SetTransformation() [1/2]

void Geom2d_Transformation::SetTransformation	(	const gp_Ax2d &	FromSystem1,
		const gp_Ax2d &	ToSystem2 )

Makes a transformation allowing passage from the coordinate system "FromSystem1" to the coordinate system "ToSystem2".

SetTransformation() [2/2]

void Geom2d_Transformation::SetTransformation

(

const gp_Ax2d &

ToSystem

)

Makes the transformation allowing passage from the basic coordinate system {P(0.,0.,0.), VX (1.,0.,0.), VY (0.,1.,0.)} to the local coordinate system defined with the Ax2d ToSystem.

SetTranslation() [1/2]

void Geom2d_Transformation::SetTranslation	(	const gp_Pnt2d &	P1,
		const gp_Pnt2d &	P2 )

Makes the transformation into a translation from the point P1 to the point P2.

SetTranslation() [2/2]

void Geom2d_Transformation::SetTranslation

(

const gp_Vec2d &

V

)

Makes the transformation into a translation. V is the vector of the translation.

SetTrsf2d()

void Geom2d_Transformation::SetTrsf2d

(

const gp_Trsf2d &

T

)

Makes the transformation into a transformation T from package gp.

Transforms()

void Geom2d_Transformation::Transforms	(	double &	X,
		double &	Y ) const

Applies the transformation <me> to the triplet {X, Y}.

Trsf2d()

gp_Trsf2d Geom2d_Transformation::Trsf2d

(

)

const

Converts this transformation into a gp_Trsf2d transformation. Returns a non persistent copy of <me>. -C++: return const&.

Value()

double Geom2d_Transformation::Value	(	const int	Row,
		const int	Col ) const

Returns the coefficients of the global matrix of transformation. It is a 2 rows X 3 columns matrix.

Raised if Row < 1 or Row > 2 or Col < 1 or Col > 2

Computes the reverse transformation.

---

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

• Geom2d_Transformation.hxx