# 3.5.1.2.9 Angleint2

## Description

This function is used to return angle with two lines.

## Syntax

double Angleint2 (double px1, double py1, double px2, double py2,
double px3, double py3, double px4, double py4
[, int unit = 0, int direction = 0])

## Parameters

px1

The X-coordinate of the first point in the first line.

py1

The Y-coordinate of the first point in the first line.

px2

The X-coordinate of the second point in the first line.

py2

The Y-coordinate of the second point in the first line.

px3

The X-coordinate of the third point in the second line.

py3

The Y-coordinate of the third point in the second line.

px4

The X-coordinate of the fourth point in the second line.

py4

The Y-coordinate of the fourth point in the second line.

unit

Specify the unit of return value. 0 indicates radians and 1 indicates degrees. The default setting is radians.

direction

Specify the direction of the return value. 0 constrains the value to the first (+x,+y) and fourth (+x,-y) quadrant. 1 returns values from 0 to 2PI radians or 0 to 360 degrees.

## Return

Returns an angle as a double value in units of radians or degrees.

## Example

double ff=angleint2(1,1,3,3,5,7,6,9,0);
ff=;   //Should return 0.32175055439664.