Given a point (x,y), how do I calculate the angle from the x-axis?
| . <- (x,y)
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| /
| /
|/
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Currently I have
Math.atan(y/x) * 180 / Math.PI;
However, this does not represent all the coordinates properly. Here are the results for this in each of the quadrants (counterclockwise).
Quadrant 1: 0 -> -90
Quadrant 2: 90 -> 0
Quadrant 3: 0 -> -90
Quadrant 4: 90 -> 0
How can I write a statement that will give me the angle from the x-axis of any point such that the results for the quadrants look like this.
Quadrant 1: 0 -> 90
Quadrant 2: 90 -> 180
Quadrant 3: 180 -> 270
Quadrant 4: 270 -> 360
Basically how do I make this work in all four quadrants?
Use
Math.atan2()
because it returns a value from 0->180 in the first two quadrants and -180->0 in the last 2.