ILLine Interface Reference

This interface represents a single straight line(LLine object). More...

Inheritance diagram for ILLine:

Public Member Functions
double	AcuteAngle (ILLine *line)
double	AngleTo (ILLine *line)
ILLine *	BisectLine (ILLine *line)
double	Distance (ILLine *line)
void	Draw (HDC hdc, double zoomX, double zoomY, double panX, double panY)
void	FromRotRectRegion (ILRotRectRegion *val)
double	GetAngle ()
ILPoint *	GetEndPoint ()
double	GetLength ()
ILPoint *	GetMidPoint ()
ILPoint *	GetStartPoint ()
double	GetX (double y)
double	GetY (double x)
LPVIntersectType	IntersectCircle (ILCircle *circle, ILPoints **intersectPoints)
LPVIntersectType	IntersectLine (ILLine *line, ILPoint **intersectPoint)
LPVIntersectType	IntersectPoly (ILPolygon *polygon, ILPoints **intersectPoints)
double	Parallel (ILLine *line)
double	Perpendicular (ILPoint *point, ILPoint **rootPoint)
ILPolygon *	Resample (int num)
ILPolygon *	ResampleByStep (double step, double stepThreshold)
void	Set (double x1, double y1, double x2, double y2)
void	Set2 (double midx, double midy, double lineAngle, double length)
ILRotRectRegion *	ToRotRectRegion (int exp)
ILLine *	Transform (ILTransform *tf)
ILLine *	Translate (double offsetX, double offsetY)
Public Member Functions inherited from ILObject
ILObject *	Copy ()
LPVErrorCode	Load (LString filename)
void	Reset ()
LPVErrorCode	Save (LString filename)
BOOL	Valid ()

Properties
double	X1 [get, set]
	The x-coordinate of the start point of the line.
double	X2 [get, set]
	The x-coordinate of the end point of the line.
double	Y1 [get, set]
	The y-coordinate of the start point of the line.
double	Y2 [get, set]
	The y-coordinate of the end point of the line.

Detailed Description

This interface represents a single straight line(LLine object).

Member Function Documentation

AcuteAngle()

double AcuteAngle

(

ILLine *

line

)

Calculate the acute angle between this and the input line.

Parameters

[in]

line

The input line

Return values

result

Return the acute angle.

AngleTo()

double AngleTo

(

ILLine *

line

)

Calculate the clockwise angle from the this line to the input line.

Parameters

[in]

line

The input line

Return values

result

Return the angle.

BisectLine()

ILLine* BisectLine

(

ILLine *

line

)

Calculate the bisect line of this and the input line.

Parameters

[in]

line

The input line

Return values

result

Return the bisect line.

Distance()

double Distance

(

ILLine *

line

)

Calculate the distance between this and the input line. For non-parallel lines, the result is calculated as the average perpendicular distance between the middle point of one line to the other.

Parameters

[in]

line

The input line

Return values

result

Return the bisect line.

Draw()

void Draw	(	HDC	hdc,
		double	zoomX,
		double	zoomY,
		double	panX,
		double	panY
	)

Draw the line on HDC.

See also

Use Draw Functions

Remarks

This function is currently not available on Linux / MacOS platform.

FromRotRectRegion()

void FromRotRectRegion

(

ILRotRectRegion *

val

)

Set placement of the line from the input rotated rectangle region. The angle is the same as the rotated rectangle region, the length is the same as the region's width.

GetAngle()

double GetAngle

(

)

Get the angle of the line

Return values

result

Return the angle.

GetEndPoint()

ILPoint* GetEndPoint

(

)

Get the end point of the line \( (X2, Y2) \)

Since

2.1.0

GetLength()

double GetLength

(

)

Get the length of the line segment

Return values

result

Return the length.

GetMidPoint()

ILPoint* GetMidPoint

(

)

Get the middle point of the line

GetStartPoint()

ILPoint* GetStartPoint

(

)

Get the start point of the line \( (X1, Y1) \)

Since

2.1.0

GetX()

double GetX

(

double

y

)

Get the x-coordinate of a point on the line with the its y-coordinate

Parameters

[in]

y

The y-coordinate of the point on the line

Return values

x	Return the x-coordinate of the point on the line

GetY()

double GetY

(

double

x

)

Get the y-coordinate of a point on the line with the its x-coordinate

Parameters

[in]

x

The x-coordinate of the point on the line

Return values

y	Return the y-coordinate of the point on the line

IntersectCircle()

LPVIntersectType IntersectCircle	(	ILCircle *	circle,
		ILPoints **	intersectPoints
	)

Determines whether this line intersects with the given circle. Return the intersection points if they are intersected.

Parameters

[in]	circle	The input circle
[out]	intersectPoints	Output the intersection points, it should be an empty set for not-intersected case, or 1 point for tangent case, or 2 points for intersected case.

Return values

type	Return the intersection type depends on the count of intersection points which is on the line segment, Bounded (2), Partial (1) or Unbounded (0).

See also

ILCircle::IntersectLine().

IntersectLine()

LPVIntersectType IntersectLine	(	ILLine *	line,
		ILPoint **	intersectPoint
	)

Determines whether this line intersects with the given line. Return the intersection point if they are intersected.

Parameters

[in]	line	The input line
[out]	intersectPoint	Output the intersection point.

Return values

type	Return the intersection type depends on whether the intersection point is on the two line segments,

IntersectPoly()

LPVIntersectType IntersectPoly	(	ILPolygon *	polygon,
		ILPoints **	intersectPoints
	)

Determines whether this line intersects with the given polygon. Return the intersection points if they are intersected.

Parameters

[in]	polygon	The input polygon
[out]	intersectPoints	Output the intersection points, it should be an empty set for not-intersected case, 1 or more points for intersected case.

Return values

type	Return the intersection type depends on the count of intersection points which is on the line segment, Bounded (all), Partial (part) or Unbounded (none).

See also

ILPolygon::IntersectLine().

Parallel()

double Parallel

(

ILLine *

line

)

Evaluate whether this and the input line are parallel

Parameters

[in]

line

The input line

Return values

result

Return the evaluation result, it's a value in (0, 1). For two perfect parallel lines, it's 1.

Perpendicular()

double Perpendicular	(	ILPoint *	point,
		ILPoint **	rootPoint
	)

Calculate the perpendicular distance and root from the given point to this line.

Parameters

[in]	point	The input point
[out]	rootPoint	Output the root point.

Return values

distance

Return the distance.

Resample()

ILPolygon* Resample

(

int

num

)

Resample the line object into an open polygon of the specified vertex count. The start and end point is always kept in the resampled result.

Parameters

[in]

num

The count of the resampled vertexes, at least 2

Return values

result

Return the resampling result polygon

See also

ResampleByStep()

ResampleByStep()

ILPolygon* ResampleByStep	(	double	step,
		double	stepThreshold
	)

Resample the line object into an open polygon, based on the given fixed interval step. The start and end point is always kept in the resampled result.

Parameters

[in]	step	The interval step.
[in]	stepThreshold	The last resampling vertex (near the end point of the line) should be omitted if the remaining length is smaller than the threshold. By default, it's 0 means \( Step / 4 \).

Return values

result

Return the resampling result polygon

See also

Resample()

Set()

void Set	(	double	x1,
		double	y1,
		double	x2,
		double	y2
	)

Set placement of the line use two end points

Parameters

[in]	x1	The x-coordinate of the start point of the line
[in]	y1	The y-coordinate of the start point of the line
[in]	x2	The x-coordinate of the end point of the line
[in]	y2	The y-coordinate of the end point of the line

Set2()

void Set2	(	double	midx,
		double	midy,
		double	lineAngle,
		double	length
	)

Set placement of the line use the middle point and angle

Parameters

[in]	midx	The x-coordinate of the middle point of the line
[in]	midy	The y-coordinate of the middle point of the line
[in]	lineAngle	The angle of the line
[in]	length	The length of the line

ToRotRectRegion()

ILRotRectRegion* ToRotRectRegion

(

int

exp

)

Generate a rotated rectangle region use the line object with the given expansion

Parameters

[in]

exp

The expansion pixels on the both side of the line's placement

Return values

val	Return the rotated rectangle region

Transform()

ILLine* Transform

(

ILTransform *

tf

)

Transform the line via the given transformation and return a new line

Parameters

[in]

tf

The transformation.

Return values

Return

the new line

Translate()

ILLine* Translate	(	double	offsetX,
		double	offsetY
	)

Translate the line by the given offset and return a new line

Parameters

[in]	offsetX	The x-coordinate of the offset
[in]	offsetY	The y-coordinate of the offset

Return values

result

Return the new line