| /***************************************************************************/ |
| /* */ |
| /* 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_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 ); |
| /* */ |
| |
| |
| FT_END_HEADER |
| |
| #endif /* __FTTRIGON_H__ */ |
| |
| |
| /* END */ |
