Hatch_Hatcher Class Reference

The Hatcher is an algorithm to compute cross hatchings in a 2d plane. It is mainly dedicated to display purpose. More...

#include <Hatch_Hatcher.hxx>

Public Member Functions
	Hatch_Hatcher (const double Tol, const bool Oriented=true)
	Returns an empty hatcher. <Tol> is the tolerance for intersections.
void	Tolerance (const double Tol)
double	Tolerance () const
void	AddLine (const gp_Lin2d &L, const Hatch_LineForm T=Hatch_ANYLINE)
	Add a line <L> to be trimmed. <T> the type is only kept from information. It is not used in the computation.
void	AddLine (const gp_Dir2d &D, const double Dist)
	Add an infinite line on direction <D> at distance <Dist> from the origin to be trimmed. <Dist> may be negative.
void	AddXLine (const double X)
	Add an infinite line parallel to the Y-axis at abciss <X>.
void	AddYLine (const double Y)
	Add an infinite line parallel to the X-axis at ordinate <Y>.
void	Trim (const gp_Lin2d &L, const int Index=0)
	Trims the lines at intersections with <L>.
void	Trim (const gp_Lin2d &L, const double Start, const double End, const int Index=0)
	Trims the lines at intersections with <L> in the parameter range <Start>, <End>
void	Trim (const gp_Pnt2d &P1, const gp_Pnt2d &P2, const int Index=0)
	Trims the line at intersection with the oriented segment P1,P2.
int	NbIntervals () const
	Returns the total number of intervals on all the lines.
int	NbLines () const
	Returns the number of lines.
const gp_Lin2d &	Line (const int I) const
	Returns the line of index .
Hatch_LineForm	LineForm (const int I) const
	Returns the type of the line of index .
bool	IsXLine (const int I) const
	Returns True if the line of index has a constant X value.
bool	IsYLine (const int I) const
	Returns True if the line of index has a constant Y value.
double	Coordinate (const int I) const
	Returns the X or Y coordinate of the line of index if it is a X or a Y line.
int	NbIntervals (const int I) const
	Returns the number of intervals on line of index .
double	Start (const int I, const int J) const
	Returns the first parameter of interval <J> on line .
void	StartIndex (const int I, const int J, int &Index, double &Par2) const
	Returns the first Index and Par2 of interval <J> on line .
double	End (const int I, const int J) const
	Returns the last parameter of interval <J> on line .
void	EndIndex (const int I, const int J, int &Index, double &Par2) const
	Returns the last Index and Par2 of interval <J> on line .

Detailed Description

The Hatcher is an algorithm to compute cross hatchings in a 2d plane. It is mainly dedicated to display purpose.

Computing cross hatchings is a 3 steps process :

1. The users stores in the Hatcher a set of 2d lines to be trimmed. Methods in the "Lines" category.
2. The user trims the lines with a boundary. The inside of a boundary is on the left side. Methods in the "Trimming" category.
3. The user reads back the trimmed lines. Methods in the "Results" category.

The result is a set of parameter intervals on the line. The first parameter of an Interval may be RealFirst() and the last may be RealLast().

A line can be a line parallel to the axis (X or Y line or a 2D line.

The Hatcher has two modes :

• The "Oriented" mode, where the orientation of the trimming curves is considered. The hatch are kept on the left of the trimming curve. In this mode infinite hatch can be computed.
• The "UnOriented" mode, where the hatch are always finite.

Constructor & Destructor Documentation

Hatch_Hatcher()

Hatch_Hatcher::Hatch_Hatcher	(	const double	Tol,
		const bool	Oriented = true )

Returns an empty hatcher. <Tol> is the tolerance for intersections.

Member Function Documentation

AddLine() [1/2]

void Hatch_Hatcher::AddLine	(	const gp_Dir2d &	D,
		const double	Dist )

Add an infinite line on direction <D> at distance <Dist> from the origin to be trimmed. <Dist> may be negative.

If O is the origin of the 2D plane, and V the vector perpendicular to D (in the direct direction).

A point P is on the line if : OP dot V = Dist The parameter of P on the line is OP dot D

AddLine() [2/2]

void Hatch_Hatcher::AddLine	(	const gp_Lin2d &	L,
		const Hatch_LineForm	T = Hatch_ANYLINE )

Add a line <L> to be trimmed. <T> the type is only kept from information. It is not used in the computation.

AddXLine()

void Hatch_Hatcher::AddXLine

(

const double

X

)

Add an infinite line parallel to the Y-axis at abciss <X>.

AddYLine()

void Hatch_Hatcher::AddYLine

(

const double

Y

)

Add an infinite line parallel to the X-axis at ordinate <Y>.

Coordinate()

double Hatch_Hatcher::Coordinate

(

const int

I

)

const

Returns the X or Y coordinate of the line of index if it is a X or a Y line.

End()

double Hatch_Hatcher::End	(	const int	I,
		const int	J ) const

Returns the last parameter of interval <J> on line .

EndIndex()

void Hatch_Hatcher::EndIndex	(	const int	I,
		const int	J,
		int &	Index,
		double &	Par2 ) const

Returns the last Index and Par2 of interval <J> on line .

IsXLine()

bool Hatch_Hatcher::IsXLine

(

const int

I

)

const

Returns True if the line of index has a constant X value.

IsYLine()

bool Hatch_Hatcher::IsYLine

(

const int

I

)

const

Returns True if the line of index has a constant Y value.

Line()

const gp_Lin2d & Hatch_Hatcher::Line

(

const int

I

)

const

Returns the line of index .

LineForm()

Hatch_LineForm Hatch_Hatcher::LineForm

(

const int

I

)

const

Returns the type of the line of index .

NbIntervals() [1/2]

int Hatch_Hatcher::NbIntervals

(

)

const

Returns the total number of intervals on all the lines.

NbIntervals() [2/2]

int Hatch_Hatcher::NbIntervals

(

const int

I

)

const

Returns the number of intervals on line of index .

NbLines()

int Hatch_Hatcher::NbLines

(

)

const

Returns the number of lines.

Start()

double Hatch_Hatcher::Start	(	const int	I,
		const int	J ) const

Returns the first parameter of interval <J> on line .

StartIndex()

void Hatch_Hatcher::StartIndex	(	const int	I,
		const int	J,
		int &	Index,
		double &	Par2 ) const

Returns the first Index and Par2 of interval <J> on line .

Tolerance() [1/2]

double Hatch_Hatcher::Tolerance

(

)

const

Tolerance() [2/2]

void Hatch_Hatcher::Tolerance

(

const double

Tol

)

Trim() [1/3]

void Hatch_Hatcher::Trim	(	const gp_Lin2d &	L,
		const double	Start,
		const double	End,
		const int	Index = 0 )

Trims the lines at intersections with <L> in the parameter range <Start>, <End>

Trim() [2/3]

void Hatch_Hatcher::Trim	(	const gp_Lin2d &	L,
		const int	Index = 0 )

Trims the lines at intersections with <L>.

Trim() [3/3]

void Hatch_Hatcher::Trim	(	const gp_Pnt2d &	P1,
		const gp_Pnt2d &	P2,
		const int	Index = 0 )

Trims the line at intersection with the oriented segment P1,P2.

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

• Hatch_Hatcher.hxx