# Atan2F16

Computes the arctangent of a ratio.

### Synopsis

`frac16 Atan2F16( frac16 x, frac16 y )`

### Description

This function computes the arctangent of the ratio y/x.

The result assumes 256.0 units in the circle (or 16,777,216 units if used as an integer). A correct 16.16 result is returned if the arguments are int32, frac30 or frac14, as long as both arguments are the same type.

### Arguments

x, y 16.16-format fractions.

### Return Value

The function returns the arctangent of the ratio of the arguments.

### Implementation

Folio call implemented in operamath V20.

### Associated Files

operamath.h, operamath.lib