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Name 
atan2() 
Examples  void draw() {
background(204);
translate(width/2, height/2);
float a = atan2(mouseYheight/2, mouseXwidth/2);
rotate(a);
rect(30, 5, 60, 10);
}

Description 
Calculates the angle (in radians) from a specified point to the coordinate origin as measured from the positive xaxis. Values are returned as a float in the range from PI to PI. The atan2() function is most often used for orienting geometry to the position of the cursor. Note: The ycoordinate of the point is the first parameter, and the xcoordinate is the second parameter, due the the structure of calculating the tangent.

Syntax  atan2(y, x) 
Parameters 
y 
float: ycoordinate of the point 
x 
float: xcoordinate of the point 

Returns  float 
Related  tan()

Updated on March 16, 2016 10:39:06am EDT