1 /***************************************************************************/

     2 /*                                                                         */

     3 /*  fttrigon.h                                                             */

     4 /*                                                                         */

     5 /*    FreeType trigonometric functions (specification).                    */

     6 /*                                                                         */

     7 /*  Copyright 2001, 2003, 2005, 2007 by                                    */

     8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */

     9 /*                                                                         */

    10 /*  This file is part of the FreeType project, and may only be used,       */

    11 /*  modified, and distributed under the terms of the FreeType project      */

    12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */

    13 /*  this file you indicate that you have read the license and              */

    14 /*  understand and accept it fully.                                        */

    15 /*                                                                         */

    16 /***************************************************************************/

    17 

    18 

    19 #ifndef __FTTRIGON_H__

    20 #define __FTTRIGON_H__

    21 

    22 #include FT_FREETYPE_H

    23 

    24 #ifdef FREETYPE_H

    25 #error "freetype.h of FreeType 1 has been loaded!"

    26 #error "Please fix the directory search order for header files"

    27 #error "so that freetype.h of FreeType 2 is found first."

    28 #endif

    29 

    30 

    31 FT_BEGIN_HEADER

    32 

    33 

    34   /*************************************************************************/

    35   /*                                                                       */

    36   /* <Section>                                                             */

    37   /*   computations                                                        */

    38   /*                                                                       */

    39   /*************************************************************************/

    40 

    41 

    42   /*************************************************************************

    43    *

    44    * @type:

    45    *   FT_Angle

    46    *

    47    * @description:

    48    *   This type is used to model angle values in FreeType.  Note that the

    49    *   angle is a 16.16 fixed float value expressed in degrees.

    50    *

    51    */

    52   typedef FT_Fixed  FT_Angle;

    53 

    54 

    55   /*************************************************************************

    56    *

    57    * @macro:

    58    *   FT_ANGLE_PI

    59    *

    60    * @description:

    61    *   The angle pi expressed in @FT_Angle units.

    62    *

    63    */

    64 #define FT_ANGLE_PI  ( 180L << 16 )

    65 

    66 

    67   /*************************************************************************

    68    *

    69    * @macro:

    70    *   FT_ANGLE_2PI

    71    *

    72    * @description:

    73    *   The angle 2*pi expressed in @FT_Angle units.

    74    *

    75    */

    76 #define FT_ANGLE_2PI  ( FT_ANGLE_PI * 2 )

    77 

    78 

    79   /*************************************************************************

    80    *

    81    * @macro:

    82    *   FT_ANGLE_PI2

    83    *

    84    * @description:

    85    *   The angle pi/2 expressed in @FT_Angle units.

    86    *

    87    */

    88 #define FT_ANGLE_PI2  ( FT_ANGLE_PI / 2 )

    89 

    90 

    91   /*************************************************************************

    92    *

    93    * @macro:

    94    *   FT_ANGLE_PI4

    95    *

    96    * @description:

    97    *   The angle pi/4 expressed in @FT_Angle units.

    98    *

    99    */

   100 #define FT_ANGLE_PI4  ( FT_ANGLE_PI / 4 )

   101 

   102 

   103   /*************************************************************************

   104    *

   105    * @function:

   106    *   FT_Sin

   107    *

   108    * @description:

   109    *   Return the sinus of a given angle in fixed point format.

   110    *

   111    * @input:

   112    *   angle ::

   113    *     The input angle.

   114    *

   115    * @return:

   116    *   The sinus value.

   117    *

   118    * @note:

   119    *   If you need both the sinus and cosinus for a given angle, use the

   120    *   function @FT_Vector_Unit.

   121    *

   122    */

   123   FT_EXPORT( FT_Fixed )

   124   FT_Sin( FT_Angle  angle );

   125 

   126 

   127   /*************************************************************************

   128    *

   129    * @function:

   130    *   FT_Cos

   131    *

   132    * @description:

   133    *   Return the cosinus of a given angle in fixed point format.

   134    *

   135    * @input:

   136    *   angle ::

   137    *     The input angle.

   138    *

   139    * @return:

   140    *   The cosinus value.

   141    *

   142    * @note:

   143    *   If you need both the sinus and cosinus for a given angle, use the

   144    *   function @FT_Vector_Unit.

   145    *

   146    */

   147   FT_EXPORT( FT_Fixed )

   148   FT_Cos( FT_Angle  angle );

   149 

   150 

   151   /*************************************************************************

   152    *

   153    * @function:

   154    *   FT_Tan

   155    *

   156    * @description:

   157    *   Return the tangent of a given angle in fixed point format.

   158    *

   159    * @input:

   160    *   angle ::

   161    *     The input angle.

   162    *

   163    * @return:

   164    *   The tangent value.

   165    *

   166    */

   167   FT_EXPORT( FT_Fixed )

   168   FT_Tan( FT_Angle  angle );

   169 

   170 

   171   /*************************************************************************

   172    *

   173    * @function:

   174    *   FT_Atan2

   175    *

   176    * @description:

   177    *   Return the arc-tangent corresponding to a given vector (x,y) in

   178    *   the 2d plane.

   179    *

   180    * @input:

   181    *   x ::

   182    *     The horizontal vector coordinate.

   183    *

   184    *   y ::

   185    *     The vertical vector coordinate.

   186    *

   187    * @return:

   188    *   The arc-tangent value (i.e. angle).

   189    *

   190    */

   191   FT_EXPORT( FT_Angle )

   192   FT_Atan2( FT_Fixed  x,

   193             FT_Fixed  y );

   194 

   195 

   196   /*************************************************************************

   197    *

   198    * @function:

   199    *   FT_Angle_Diff

   200    *

   201    * @description:

   202    *   Return the difference between two angles.  The result is always

   203    *   constrained to the ]-PI..PI] interval.

   204    *

   205    * @input:

   206    *   angle1 ::

   207    *     First angle.

   208    *

   209    *   angle2 ::

   210    *     Second angle.

   211    *

   212    * @return:

   213    *   Constrained value of `value2-value1'.

   214    *

   215    */

   216   FT_EXPORT( FT_Angle )

   217   FT_Angle_Diff( FT_Angle  angle1,

   218                  FT_Angle  angle2 );

   219 

   220 

   221   /*************************************************************************

   222    *

   223    * @function:

   224    *   FT_Vector_Unit

   225    *

   226    * @description:

   227    *   Return the unit vector corresponding to a given angle.  After the

   228    *   call, the value of `vec.x' will be `sin(angle)', and the value of

   229    *   `vec.y' will be `cos(angle)'.

   230    *

   231    *   This function is useful to retrieve both the sinus and cosinus of a

   232    *   given angle quickly.

   233    *

   234    * @output:

   235    *   vec ::

   236    *     The address of target vector.

   237    *

   238    * @input:

   239    *   angle ::

   240    *     The address of angle.

   241    *

   242    */

   243   FT_EXPORT( void )

   244   FT_Vector_Unit( FT_Vector*  vec,

   245                   FT_Angle    angle );

   246 

   247 

   248   /*************************************************************************

   249    *

   250    * @function:

   251    *   FT_Vector_Rotate

   252    *

   253    * @description:

   254    *   Rotate a vector by a given angle.

   255    *

   256    * @inout:

   257    *   vec ::

   258    *     The address of target vector.

   259    *

   260    * @input:

   261    *   angle ::

   262    *     The address of angle.

   263    *

   264    */

   265   FT_EXPORT( void )

   266   FT_Vector_Rotate( FT_Vector*  vec,

   267                     FT_Angle    angle );

   268 

   269 

   270   /*************************************************************************

   271    *

   272    * @function:

   273    *   FT_Vector_Length

   274    *

   275    * @description:

   276    *   Return the length of a given vector.

   277    *

   278    * @input:

   279    *   vec ::

   280    *     The address of target vector.

   281    *

   282    * @return:

   283    *   The vector length, expressed in the same units that the original

   284    *   vector coordinates.

   285    *

   286    */

   287   FT_EXPORT( FT_Fixed )

   288   FT_Vector_Length( FT_Vector*  vec );

   289 

   290 

   291   /*************************************************************************

   292    *

   293    * @function:

   294    *   FT_Vector_Polarize

   295    *

   296    * @description:

   297    *   Compute both the length and angle of a given vector.

   298    *

   299    * @input:

   300    *   vec ::

   301    *     The address of source vector.

   302    *

   303    * @output:

   304    *   length ::

   305    *     The vector length.

   306    *

   307    *   angle ::

   308    *     The vector angle.

   309    *

   310    */

   311   FT_EXPORT( void )

   312   FT_Vector_Polarize( FT_Vector*  vec,

   313                       FT_Fixed   *length,

   314                       FT_Angle   *angle );

   315 

   316 

   317   /*************************************************************************

   318    *

   319    * @function:

   320    *   FT_Vector_From_Polar

   321    *

   322    * @description:

   323    *   Compute vector coordinates from a length and angle.

   324    *

   325    * @output:

   326    *   vec ::

   327    *     The address of source vector.

   328    *

   329    * @input:

   330    *   length ::

   331    *     The vector length.

   332    *

   333    *   angle ::

   334    *     The vector angle.

   335    *

   336    */

   337   FT_EXPORT( void )

   338   FT_Vector_From_Polar( FT_Vector*  vec,

   339                         FT_Fixed    length,

   340                         FT_Angle    angle );

   341 

   342   /* */

   343 

   344 

   345 FT_END_HEADER

   346 

   347 #endif /* __FTTRIGON_H__ */

   348 

   349 

   350 /* END */