angle_lx

Herror ::angle_lx ( const HTuple &Row1, const HTuple &Column1, const HTuple &Row2, const HTuple &Column2, double *Angle ) Herror ::angle_lx ( const HTuple &Row1, const HTuple &Column1, const HTuple &Row2, const HTuple &Column2, HTuple *Angle )

Calculate the angle between one line and the vertical axis.

The operator ::angle_lx calculates the angle between one line and the abscissa. As input the row and column of the line (Row1,Column1, Row2,Column2) are expected. The calculation in done as follows: We interprete the line as a vector with starting point Row1,Column1 and end point Row2,Column2. Turning the vector counter clockwise onto the abscissa (center of rotation is the intersection point of the abscissa) yields the angle. The result is dependant on the order of points of line. The parameters Angle returns the angle in radians. The angles range from -pi <= Angle <= pi.

Parameters

`Row1` (input_control)	point.y(-array) `->` HTuple.double / long
Row of the first point of the line.

`Column1` (input_control)	point.x(-array) `->` HTuple.double / long
Column of the first point of the line.

`Row2` (input_control)	point.y(-array) `->` HTuple.double / long
Row of the second point of the line.

`Column2` (input_control)	point.x(-array) `->` HTuple.double / long
Column of the second point of the line.

`Angle` (output_control)	number(-array) `->` (HTuple.) double *
Angle between the line and the abscissa.

Example

RowX1 := 255
ColumnX1 := 10
RowX2 := 255
ColumnX2 := 501
disp_line (WindowHandle, RowX1, ColumnX1, RowX2, ColumnX2)
Row1 := 255
Column1 := 255
for i := 1 to 360 by 1
  Row2 := 255 + sin(rad(i)) * 200
  Column2 := 255 + cos(rad(i)) * 200
  disp_line (WindowHandle, Row1, Column1, Row2, Column2)
  angle_lx (Row1, Column1, Row2, Column2, Angle)
endfor

Result

::angle_lx returns H_MSG_TRUE.

Alternatives

::angle_ll

Module

Basic operators