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Editing: fttrigon.h
/***************************************************************************/ /* */ /* fttrigon.h */ /* */ /* FreeType trigonometric functions (specification). */ /* */ /* Copyright 2001-2018 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-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 `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 `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 */
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