/****************************************************************************
*
* fttrigon.h
*
* FreeType trigonometric functions (specification).
*
* Copyright (C) 2001-2020 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT. By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/
#ifndef FTTRIGON_H_
#define FTTRIGON_H_
#include <freetype/freetype.h>
#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif
FT_BEGIN_HEADER
/**************************************************************************
*
* @section:
* computations
*
*/
/**************************************************************************
*
* @type:
* FT_Angle
*
* @description:
* This type is used to model angle values in FreeType. Note that the
* angle is a 16.16 fixed-point value expressed in degrees.
*
*/
typedef FT_Fixed FT_Angle;
/**************************************************************************
*
* @macro:
* FT_ANGLE_PI
*
* @description:
* The angle pi expressed in @FT_Angle units.
*
*/
#define FT_ANGLE_PI ( 180L << 16 )
/**************************************************************************
*
* @macro:
* FT_ANGLE_2PI
*
* @description:
* The angle 2*pi expressed in @FT_Angle units.
*
*/
#define FT_ANGLE_2PI ( FT_ANGLE_PI * 2 )
/**************************************************************************
*
* @macro:
* FT_ANGLE_PI2
*
* @description:
* The angle pi/2 expressed in @FT_Angle units.
*
*/
#define FT_ANGLE_PI2 ( FT_ANGLE_PI / 2 )
/**************************************************************************
*
* @macro:
* FT_ANGLE_PI4
*
* @description:
* The angle pi/4 expressed in @FT_Angle units.
*
*/
#define FT_ANGLE_PI4 ( FT_ANGLE_PI / 4 )
/**************************************************************************
*
* @function:
* FT_Sin
*
* @description:
* Return the sinus of a given angle in fixed-point format.
*
* @input:
* angle ::
* The input angle.
*
* @return:
* The sinus value.
*
* @note:
* If you need both the sinus and cosinus for a given angle, use the
* function @FT_Vector_Unit.
*
*/
FT_EXPORT( FT_Fixed )
FT_Sin( FT_Angle angle );
/**************************************************************************
*
* @function:
* FT_Cos
*
* @description:
* Return the cosinus of a given angle in fixed-point format.
*
* @input:
* angle ::
* The input angle.
*
* @return:
* The cosinus value.
*
* @note:
* If you need both the sinus and cosinus for a given angle, use the
* function @FT_Vector_Unit.
*
*/
FT_EXPORT( FT_Fixed )
FT_Cos( FT_Angle angle );
/**************************************************************************
*
* @function:
* FT_Tan
*
* @description:
* Return the tangent of a given angle in fixed-point format.
*
* @input:
* angle ::
* The input angle.
*
* @return:
* The tangent value.
*
*/
FT_EXPORT( FT_Fixed )
FT_Tan( FT_Angle angle );
/**************************************************************************
*
* @function:
* FT_Atan2
*
* @description:
* Return the arc-tangent corresponding to a given vector (x,y) in the 2d
* plane.
*
* @input:
* x ::
* The horizontal vector coordinate.
*
* y ::
* The vertical vector coordinate.
*
* @return:
* The arc-tangent value (i.e. angle).
*
*/
FT_EXPORT( FT_Angle )
FT_Atan2( FT_Fixed x,
FT_Fixed y );
/**************************************************************************
*
* @function:
* FT_Angle_Diff
*
* @description:
* Return the difference between two angles. The result is always
* constrained to the ]-PI..PI] interval.
*
* @input:
* angle1 ::
* First angle.
*
* angle2 ::
* Second angle.
*
* @return:
* Constrained value of `angle2-angle1`.
*
*/
FT_EXPORT( FT_Angle )
FT_Angle_Diff( FT_Angle angle1,
FT_Angle angle2 );
/**************************************************************************
*
* @function:
* FT_Vector_Unit
*
* @description:
* Return the unit vector corresponding to a given angle. After the
* call, the value of `vec.x` will be `cos(angle)`, and the value of
* `vec.y` will be `sin(angle)`.
*
* This function is useful to retrieve both the sinus and cosinus of a
* given angle quickly.
*
* @output:
* vec ::
* The address of target vector.
*
* @input:
* angle ::
* The input angle.
*
*/
FT_EXPORT( void )
FT_Vector_Unit( FT_Vector* vec,
FT_Angle angle );
/**************************************************************************
*
* @function:
* FT_Vector_Rotate
*
* @description:
* Rotate a vector by a given angle.
*
* @inout:
* vec ::
* The address of target vector.
*
* @input:
* angle ::
* The input angle.
*
*/
FT_EXPORT( void )
FT_Vector_Rotate( FT_Vector* vec,
FT_Angle angle );
/**************************************************************************
*
* @function:
* FT_Vector_Length
*
* @description:
* Return the length of a given vector.
*
* @input:
* vec ::
* The address of target vector.
*
* @return:
* The vector length, expressed in the same units that the original
* vector coordinates.
*
*/
FT_EXPORT( FT_Fixed )
FT_Vector_Length( FT_Vector* vec );
/**************************************************************************
*
* @function:
* FT_Vector_Polarize
*
* @description:
* Compute both the length and angle of a given vector.
*
* @input:
* vec ::
* The address of source vector.
*
* @output:
* length ::
* The vector length.
*
* angle ::
* The vector angle.
*
*/
FT_EXPORT( void )
FT_Vector_Polarize( FT_Vector* vec,
FT_Fixed *length,
FT_Angle *angle );
/**************************************************************************
*
* @function:
* FT_Vector_From_Polar
*
* @description:
* Compute vector coordinates from a length and angle.
*
* @output:
* vec ::
* The address of source vector.
*
* @input:
* length ::
* The vector length.
*
* angle ::
* The vector angle.
*
*/
FT_EXPORT( void )
FT_Vector_From_Polar( FT_Vector* vec,
FT_Fixed length,
FT_Angle angle );
/* */
FT_END_HEADER
#endif /* FTTRIGON_H_ */
/* END */
