misc/libfreetype/include/freetype/fttrigon.h
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/include/freetype/fttrigon.h	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,350 @@
+/***************************************************************************/
+/*                                                                         */
+/*  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 */