/***************************************************************************/
/*                                                                         */
/*  ahoptim.h                                                              */
/*                                                                         */
/*    FreeType auto hinting outline optimization (declaration).            */
/*                                                                         */
/*  Copyright 2000 Catharon Productions Inc.                               */
/*  Author: David Turner                                                   */
/*                                                                         */
/*  This file is part of the Catharon Typography Project and shall only    */
/*  be used, modified, and distributed under the terms of the Catharon     */
/*  Open Source License that should come with this file under the name     */
/*  `CatharonLicense.txt'.  By continuing to use, modify, or distribute    */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/*  Note that this license is compatible with the FreeType license.        */
/*                                                                         */
/***************************************************************************/


#ifndef AHOPTIM_H
#define AHOPTIM_H


#include "ahtypes.h"

/* the maximal number of stem configurations to record */
/* during optimization                                 */
#define AH_MAX_CONFIGS  8


typedef struct  AH_Stem_
{
	FT_Pos pos;          /* current position        */
	FT_Pos velocity;     /* current velocity        */
	FT_Pos force;        /* sum of current forces   */
	FT_Pos width;        /* normalized width        */

	FT_Pos min_pos;      /* minimum grid position */
	FT_Pos max_pos;      /* maximum grid position */

	AH_Edge*  edge1;     /* left/bottom edge */
	AH_Edge*  edge2;     /* right/top edge   */

	FT_Pos opos;         /* original position */
	FT_Pos owidth;       /* original width    */

	FT_Pos min_coord;    /* minimum coordinate */
	FT_Pos max_coord;    /* maximum coordinate */

} AH_Stem;


/* A spring between two stems */
typedef struct  AH_Spring_
{
	AH_Stem*  stem1;
	AH_Stem*  stem2;
	FT_Pos owidth;      /* original width  */
	FT_Pos tension;     /* current tension */

} AH_Spring;


/* A configuration records the position of each stem at a given time  */
/* as well as the associated distortion                               */
typedef struct AH_Configuration_
{
	FT_Pos*  positions;
	FT_Long distortion;

} AH_Configuration;


typedef struct  AH_Optimizer_
{
	FT_Memory memory;
	AH_Outline*       outline;

	FT_Int num_hstems;
	AH_Stem*          horz_stems;

	FT_Int num_vstems;
	AH_Stem*          vert_stems;

	FT_Int num_hsprings;
	FT_Int num_vsprings;
	AH_Spring*        horz_springs;
	AH_Spring*        vert_springs;

	FT_Int num_configs;
	AH_Configuration configs[AH_MAX_CONFIGS];
	FT_Pos*           positions;

	/* during each pass, use these instead */
	FT_Int num_stems;
	AH_Stem*          stems;

	FT_Int num_springs;
	AH_Spring*        springs;
	FT_Bool vertical;

	FT_Fixed tension_scale;
	FT_Pos tension_threshold;

} AH_Optimizer;


/* loads the outline into the optimizer */
int  AH_Optimizer_Init( AH_Optimizer*  optimizer,
						AH_Outline*    outline,
						FT_Memory memory );


/* compute optimal outline */
void  AH_Optimizer_Compute( AH_Optimizer*  optimizer );


/* release the optimization data */
void AH_Optimizer_Done( AH_Optimizer*  optimizer );


#endif /* AHOPTIM_H */


/* END */
