fttrigon.h
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上传日期:2020-08-09
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- /***************************************************************************/
- /* */
- /* 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 */