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Rev	Author	Line No.	Line
3918	Serge	1	/***************************************************************************/
		2	/* */
		3	/* fttrigon.h */
		4	/* */
		5	/* FreeType trigonometric functions (specification). */
		6	/* */
		7	/* Copyright 2001, 2003, 2005, 2007, 2013 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	/* */
		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-point 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 */

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