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  Reference for Processing (BETA) version 91+. If you have a previous version, use the reference included with your software. If you see any errors or have any comments, let us know.  
Name  

atan2()

   
Examples   
void draw() { 
  background(204); 
  translate(width/2, height/2); 
  float a = atan2(mouseY-height/2, mouseX-width/2); 
  rotate(a); 
  rect(-12, -5, 24, 10); 
}

Description   Calculates the angle (in radians) from a specified point to the coordinate origin as measured from the positive x-axis. 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 y-coordinate of the point is the first parameter and the x-coordinate is the second due the the structure of calculating the tangent.
   
Syntax   
atan2(y, x);
   
Parameters  
y   int or float: y-coordinate of the point
x   int or float: x-coordinate of the point
   
Returns   float
   
Usage   Web & Application
   
Related   tan()
  
 






    
 
Updated: Fri Jul 15 16:35:30 PDT 2005
 
 
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