/***************************************************************************//* *//* 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 FT_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 */