Name
Math.atan2( ) — compute the angle from the X-axis to a point
Availability
JavaScript 1.0; JScript 1.0; ECMAScript v1
Synopsis
Math.atan2(y
,x
)
Arguments
-
y
The Y-coordinate of the point.
-
x
The X-coordinate of the point.
Returns
A value between -π and π radians that specifies the
counterclockwise angle between the positive X-axis and the point
(x
, y
).
Description
The Math.atan2( )
function computes the arc
tangent of the ratio
y
/x
. The
y
argument can be considered the
Y-coordinate (or “rise”) of a point, and the
x
argument can be considered the
X-coordinate (or “run”) of the point. Note the unusual
order of the arguments to this function: the Y-coordinate is passed
before the X-coordinate.
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