Reference for Processing version 1.2. If you have a previous version, use the reference included with your software. If you see any errors or have suggestions, please let us know. If you prefer a more technical reference, visit the Processing Javadoc.

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 on June 14, 2010 12:05:29pm EDT

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