_ATAN2

The _ATAN2 function returns the radian angle between the positive x-axis of a plane and the point given by the coordinates (x, y) on it.

Syntax

angle! = _ATAN2( y, x)

Parameters

• y is the vertical axis position(row) as a floating point value.
• x is the horizontal axis position(column) as a floating point value.

Description

• The angle is positive for counter-clockwise angles (upper half-plane, y > 0), and negative for clockwise angles (lower half-plane, y < 0).
• _ATAN2(y, x) = ATN(y / x) when x > 0
• _ATAN2(y, x) = ATN(y / x) + _PI when x < 0 and y >= 0
• _ATAN2(y, x) = ATN(y / x) - _PI when x < 0 and y < 0
• _ATAN2(y' x) = _PI / 2 when x = 0 and y > 0
• _ATAN2(y, x) = -_PI / 2 when x = 0 and y < 0
• _ATAN2(0, 0) is undefined and returns 0.

See also

• ATN (arctangent)

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