The Math.atan2()
function returns the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y), for Math.atan2(y,x)
.
The Math.atan2()
function returns the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y), for Math.atan2(y,x)
.
Math.atan2(y, x)
y
The y coordinate of the point.
x
The x coordinate of the point
The angle in radians (in $[-\backslash pi,\; \backslash pi]$) between the positive x-axis and the ray from (0,0) to the point (x,y).
The Math.atan2()
method returns a numeric value between -π and π representing the angle theta of an (x, y)
point. This is the counterclockwise angle, measured in radians, between the positive X axis, and the point (x, y)
. Note that the arguments to this function pass the y-coordinate first and the x-coordinate second.
Math.atan2()
is passed separate x
and y
arguments, and Math.atan()
is passed the ratio of those two arguments.
Because atan2()
is a static method of Math
, you always use it as Math.atan2()
, rather than as a method of a Math
object you created (Math
is not a constructor).
Math.atan2(90, 15); // 1.4056476493802699 Math.atan2(15, 90); // 0.16514867741462683 Math.atan2(±0, -0); // ±PI. Math.atan2(±0, +0); // ±0. Math.atan2(±0, -x); // ±PI for x > 0. Math.atan2(±0, x); // ±0 for x > 0. Math.atan2(-y, ±0); // -PI/2 for y > 0. Math.atan2(y, ±0); // PI/2 for y > 0. Math.atan2(±y, -Infinity); // ±PI for finite y > 0. Math.atan2(±y, +Infinity); // ±0 for finite y > 0. Math.atan2(±Infinity, x); // ±PI/2 for finite x. Math.atan2(±Infinity, -Infinity); // ±3*PI/4. Math.atan2(±Infinity, +Infinity); // ±PI/4.
Specification |
---|
ECMAScript Language Specification # sec-math.atan2 |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
atan2 |
1 |
12 |
1 |
4 |
3 |
1 |
4.4 |
18 |
4 |
10.1 |
1 |
1.0 |
1.0 |
0.10.0 |
© 2005–2022 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/atan2