www.pudn.com > freetype.rar > fttrigon.h
/***************************************************************************/
/* */
/* fttrigon.h */
/* */
/* FreeType trigonometric functions (specification). */
/* */
/* Copyright 2001 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"
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: */
/* Contrainted 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_Normalize */
/* */
/* @description: */
/* Normalize a given vector (i.e. compute the equivalent unit */
/* vector). */
/* */
/* @inout: */
/* vec :: The address of target vector. */
/* */
FT_EXPORT( void )
FT_Vector_Normalize( 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 */