# IConstructLine Interface

Provides access to members that construct a line segment using other geometries and measures.

## Description

Methods for constructing a Line segment based either on the bisection of an angle defined by three input points or the extension of an existing Line to the boundary of the Spatial Reference.

## Members

Name Description ConstructAngleBisector Constructs a line segment being the bisector through the angle defined by the three input points. ConstructExtended Extends a line segment until one or both of its endpoints reaches the boundary of the domain of the line's associated spatial reference.

### IConstructLine.ConstructAngleBisector Method

Constructs a line segment being the bisector through the angle defined by the three input points.

``````Public Sub ConstructAngleBisector ( _
ByVal from As IPoint, _
ByVal through As IPoint, _
ByVal to As IPoint, _
ByVal Length As Double, _
ByVal useAcuteAngle As Boolean _
)
``````
``````public void ConstructAngleBisector (
IPoint from,
IPoint through,
IPoint to,
double Length,
bool useAcuteAngle
);
``````

#### Description

Constructs a Line segment of given input Length which bisects the Angle formed by the right side of the three input points. The From Point of the new Line is the Through input point. If the right side angle is smaller, the constructed Line will always bisect this angle, regardless of the value of bUseSmallerAngle. However, if the right side angle is larger, and bUseSmallerAngle is TRUE, then the constructed line will bisect the smaller angle (left side) instead of the right side reflex angle.

#### Remarks ``````// This example constructs a new line using the ConstructAngleBisector method.

// Note the usage of the acute angle.

public void ConstructLineFromAngleBisector()

{

IPoint fromPoint = new PointClass();

fromPoint.PutCoords(1, 0);

IPoint throughPoint = new PointClass();

throughPoint.PutCoords(1, 1);

IPoint toPoint = new PointClass();

toPoint.PutCoords(0, 1);

IConstructLine constructLine = new LineClass();

double distance = 1.4142135623731;

constructLine.ConstructAngleBisector(fromPoint, throughPoint, toPoint, distance, false);

ILine line = constructLine as ILine;

printProperties(line);

// Now use the the acute angle with the same data.

//Gives same results as setting dDist to -1.4142135623731 and not using

// the acute angle.

constructLine.ConstructAngleBisector(fromPoint, throughPoint, toPoint, distance, true);

ILine line2 = constructLine as ILine;

printProperties(line2);

}

private void printProperties(ILine line)

{

IPoint outFromPoint = new PointClass();

IPoint outToPoint = new PointClass();

line.QueryCoords(outFromPoint, outToPoint);

System.Windows.Forms.MessageBox.Show(outFromPoint.X + " , " +

outFromPoint.Y + " , " +

outToPoint.X + " , " +

outToPoint.Y + "\n" +

"angle = " + line.Angle);

}
``````
``````'+++ This example constructs a new line using the ConstructAngleBisector method.

'+++ Note the usage of the acute angle.

Public Sub t_Line_ConstructAngleBisector()

On Error GoTo Errorhandler

Dim pPointFrom As IPoint

Dim pPointTo As IPoint

Dim pPointThrough As IPoint

Dim pLine As ILine

Dim pCLine As IConstructLine

Dim dDist As Double

Dim pP1 As IPoint

Dim pP2 As IPoint

pPointFrom = New Point

pPointTo = New Point

pPointThrough = New Point

pLine = New Line

pCLine = New Line

pP1 = New Point

pP2 = New Point

pPointFrom.PutCoords(1, 0)

pPointTo.PutCoords(0, 1)

pPointThrough.PutCoords(1, 1)

dDist = 1.4142135623731

pCLine.ConstructAngleBisector(pPointFrom, pPointThrough, pPointTo, dDist, False)

pLine = pCLine

pLine.QueryCoords(pP1, pP2)

MsgBox(pP1.X & "," & pP1.Y & " to " & pP2.X & "," & pP2.Y _

& vbCrLf & "angle = " & pLine.Angle)

'+++ Now use the the acute angle with the same data.

'+++ Gives same results as setting dDist to -1.4142135623731 and not using

'+++ the acute angle.

pCLine.ConstructAngleBisector(pPointFrom, pPointThrough, pPointTo, dDist, True)

pLine = pCLine

pLine.QueryCoords(pP1, pP2)

MsgBox(pP1.X & "," & pP1.Y & " to " & pP2.X & "," & pP2.Y _

& vbCrLf & "angle = " & pLine.Angle)

Exit Sub

Errorhandler:

MsgBox(Err.Number & "..." & Err.Description)

Exit Sub

End Sub
``````

### IConstructLine.ConstructExtended Method

Extends a line segment until one or both of its endpoints reaches the boundary of the domain of the line's associated spatial reference.

``````Public Sub ConstructExtended ( _
ByVal inLine As ILine, _
ByVal extendHow As esriSegmentExtension _
)
``````
``````public void ConstructExtended (
ILine inLine,
esriSegmentExtension extendHow
);
``````

#### Description

Extends a line to the maximum extent of the Spatial Reference given a desired extension method.

#### Remarks

To extend a Line to another Curve, wrap the Line in a Polyline and use IConstructCurve::ConstructExtended.

## Classes that implement IConstructLine

Classes Description
Line A 2D straight line between a pair of 2D endpoints; can optionally have height, measure and ID attributes at each endpoint.