/***************************************************************************/

/*                                                                         */

/*  fttrigon.h                                                             */

/*                                                                         */

/*    FreeType trigonometric functions (specification).                    */

/*                                                                         */

/*  Copyright 2001, 2003, 2005, 2007 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 FT_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 float 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 `value2-value1'.

   *

   */

  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 `sin(angle)', and the value of

   *   `vec.y' will be `cos(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 address of 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 address of 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 */