326 lines
19 KiB
C
326 lines
19 KiB
C
/***************************************************************************/
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/* */
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/* fttrigon.h */
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/* */
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/* FreeType trigonometric functions (specification). */
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/* */
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/* Copyright 2001 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#ifndef __FTTRIGON_H__
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#define __FTTRIGON_H__
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#include FT_FREETYPE_H
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FT_BEGIN_HEADER
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/*************************************************************************/
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/* */
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/* @section: */
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/* computations */
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/* */
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/*************************************************************************/
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/*************************************************************************/
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/* */
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/* @type: */
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/* FT_Angle */
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/* */
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/* @description: */
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/* This type is used to model angle values in FreeType. Note that */
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/* the angle is a 16.16 fixed float value expressed in degrees. */
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/* */
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typedef FT_Fixed FT_Angle;
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/*************************************************************************/
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/* */
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/* @macro: */
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/* FT_ANGLE_PI */
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/* */
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/* @description: */
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/* The angle pi expressed in @FT_Angle units. */
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/* */
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#define FT_ANGLE_PI ( 180L << 16 )
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/*************************************************************************/
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/* */
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/* @macro: */
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/* FT_ANGLE_2PI */
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/* */
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/* @description: */
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/* The angle 2*pi expressed in @FT_Angle units. */
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/* */
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#define FT_ANGLE_2PI ( FT_ANGLE_PI * 2 )
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/*************************************************************************/
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/* */
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/* @macro: */
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/* FT_ANGLE_PI2 */
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/* */
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/* @description: */
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/* The angle pi/2 expressed in @FT_Angle units. */
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/* */
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#define FT_ANGLE_PI2 ( FT_ANGLE_PI / 2 )
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/*************************************************************************/
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/* */
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/* @macro: */
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/* FT_ANGLE_PI4 */
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/* */
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/* @description: */
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/* The angle pi/4 expressed in @FT_Angle units. */
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/* */
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#define FT_ANGLE_PI4 ( FT_ANGLE_PI / 4 )
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Sin */
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/* */
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/* @description: */
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/* Return the sinus of a given angle in fixed point format. */
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/* */
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/* @input: */
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/* angle :: The input angle. */
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/* */
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/* @return: */
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/* The sinus value. */
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/* */
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/* @note: */
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/* If you need both the sinus and cosinus for a given angle, use the */
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/* function @FT_Vector_Unit. */
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/* */
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FT_EXPORT( FT_Fixed )
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FT_Sin( FT_Angle angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Cos */
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/* */
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/* @description: */
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/* Return the cosinus of a given angle in fixed point format. */
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/* */
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/* @input: */
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/* angle :: The input angle. */
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/* */
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/* @return: */
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/* The cosinus value. */
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/* */
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/* @note: */
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/* If you need both the sinus and cosinus for a given angle, use the */
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/* function @FT_Vector_Unit. */
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/* */
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FT_EXPORT( FT_Fixed )
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FT_Cos( FT_Angle angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Tan */
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/* */
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/* @description: */
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/* Return the tangent of a given angle in fixed point format. */
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/* */
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/* @input: */
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/* angle :: The input angle. */
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/* */
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/* @return: */
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/* The tangent value. */
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/* */
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FT_EXPORT( FT_Fixed )
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FT_Tan( FT_Angle angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Atan2 */
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/* */
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/* @description: */
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/* Return the arc-tangent corresponding to a given vector (x,y) in */
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/* the 2d plane. */
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/* */
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/* @input: */
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/* x :: The horizontal vector coordinate. */
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/* */
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/* y :: The vertical vector coordinate. */
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/* */
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/* @return: */
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/* The arc-tangent value (i.e. angle). */
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/* */
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FT_EXPORT( FT_Angle )
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FT_Atan2( FT_Fixed x,
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FT_Fixed y );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Angle_Diff */
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/* */
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/* @description: */
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/* Return the difference between two angles. The result is always */
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/* constrained to the ]-PI..PI] interval. */
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/* */
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/* @input: */
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/* angle1 :: First angle. */
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/* */
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/* angle2 :: Second angle. */
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/* */
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/* @return: */
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/* Contrainted value of `value2-value1'. */
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/* */
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FT_EXPORT( FT_Angle )
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FT_Angle_Diff( FT_Angle angle1,
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FT_Angle angle2 );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_Unit */
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/* */
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/* @description: */
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/* Return the unit vector corresponding to a given angle. After the */
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/* call, the value of `vec.x' will be `sin(angle)', and the value of */
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/* `vec.y' will be `cos(angle)'. */
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/* */
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/* This function is useful to retrieve both the sinus and cosinus of */
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/* a given angle quickly. */
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/* */
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/* @output: */
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/* vec :: The address of target vector. */
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/* */
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/* @input: */
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/* angle :: The address of angle. */
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/* */
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FT_EXPORT( void )
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FT_Vector_Unit( FT_Vector* vec,
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FT_Angle angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_Rotate */
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/* */
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/* @description: */
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/* Rotate a vector by a given angle. */
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/* */
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/* @inout: */
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/* vec :: The address of target vector. */
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/* */
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/* @input: */
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/* angle :: The address of angle. */
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/* */
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FT_EXPORT( void )
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FT_Vector_Rotate( FT_Vector* vec,
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FT_Angle angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_Length */
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/* */
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/* @description: */
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/* Return the length of a given vector. */
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/* */
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/* @input: */
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/* vec :: The address of target vector. */
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/* */
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/* @return: */
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/* The vector length, expressed in the same units that the original */
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/* vector coordinates. */
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/* */
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FT_EXPORT( FT_Fixed )
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FT_Vector_Length( FT_Vector* vec );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_Normalize */
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/* */
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/* @description: */
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/* Normalize a given vector (i.e. compute the equivalent unit */
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/* vector). */
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/* */
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/* @inout: */
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/* vec :: The address of target vector. */
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/* */
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FT_EXPORT( void )
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FT_Vector_Normalize( FT_Vector* vec );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_Polarize */
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/* */
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/* @description: */
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/* Compute both the length and angle of a given vector. */
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/* */
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/* @input: */
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/* vec :: The address of source vector. */
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/* */
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/* @output: */
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/* length :: The vector length. */
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/* angle :: The vector angle. */
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/* */
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FT_EXPORT( void )
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FT_Vector_Polarize( FT_Vector* vec,
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FT_Fixed *length,
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FT_Angle *angle );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Vector_From_Polar */
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/* */
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/* @description: */
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/* Compute vector coordinates from a length and angle. */
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/* */
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/* @output: */
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/* vec :: The address of source vector. */
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/* */
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/* @input: */
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/* length :: The vector length. */
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/* angle :: The vector angle. */
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/* */
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FT_EXPORT( void )
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FT_Vector_From_Polar( FT_Vector* vec,
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FT_Fixed length,
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FT_Angle angle );
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/* */
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FT_END_HEADER
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#endif /* __FTTRIGON_H__ */
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/* END */
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