/*
 * The Npic library
 *
 * Copyright (C) 2003 Edouard Thiel <Edouard.Thiel@lif.univ-mrs.fr>
 *
 * This library is free software under the terms of the 
 * GNU Lesser General Public License (LGPL) version 2.1.
*/

/*
 * dist_dt.c - 07/01/2011
 *
 * Front-end for Distance Transforms
*/


#include <npic.h>


/*--------------------- P U B L I C - I N T E R F A C E ----------------------*/

/*
 * Compute the distance transform (DT) on image np for the mask mh;
 * mh is a half weighted distance mask or describe an Euclidean distance.
 *
 * Do nothing if np is not ok. set not ok on error. Verbose.
 * Return computation time in second.microsecond
*/

double NpicDT (Npic_image *np, Npic_mask *mh)
{
    int dtype;

    if (NpicDTCheckData (np, mh, __func__) != NPIC_SUCCESS) return 0;

    dtype = NpicDTFindDistType (mh);

    switch (dtype) {
        case NPIC_DIST_WEIGHTED       : return NpicWDT (np, mh); 
        case NPIC_DIST_EUCLID_SQUARED : return NpicSEDT_Hirata (np);

        default :  np->gen.ok = NpicError (__func__, NPIC_ERROR, 
                ": distance type not available");
    }
    return 0;
}


/*
 * Compute the distance transform (DT) on image np for the mask mh
 * with "infinite border", i.e border pixels, propagating no distance value;
 * mh is a half weighted distance mask or describe an Euclidean distance.
 *
 * Do nothing if np is not ok. set not ok on error. Verbose.
 * Return computation time in second.microsecond
*/

double NpicDT_inf (Npic_image *np, Npic_mask *mh)
{
    int dtype;

    if (NpicDTCheckData (np, mh, __func__) != NPIC_SUCCESS) return 0;

    dtype =  NpicDTFindDistType (mh);

    switch (dtype) {
        case NPIC_DIST_WEIGHTED       : return NpicWDT_inf (np, mh); 
        case NPIC_DIST_EUCLID_SQUARED : return NpicSEDT_Hirata_inf (np);

        default :  np->gen.ok = NpicError (__func__, NPIC_ERR_UNAV_DIST, "");
    }
    return 0;
}


/*
 * Compute the reverse weighted distance transform (DT_rev) on image np
 * for the mask mh;
 * mh is a half weighted distance mask or describe an Euclidean distance.
 *
 * Do nothing if np is not ok. set not ok on error. Verbose.
 * Return computation time in second.microsecond
*/

double NpicDT_rev (Npic_image *np, Npic_mask *mh)
{
    int dtype;

    if (NpicDTCheckData (np, mh, __func__) != NPIC_SUCCESS) return 0;

    dtype =  NpicDTFindDistType (mh);

    switch (dtype) {
        case NPIC_DIST_WEIGHTED       : return NpicWDT_rev (np, mh); 
        case NPIC_DIST_EUCLID_SQUARED : return NpicSEDT_Hirata_rev (np);

        default :  np->gen.ok = NpicError (__func__, NPIC_ERR_UNAV_DIST, "");
    }
    return 0;
}


/*-------------------- P R I V A T E - F U N C T I O N S ---------------------*/

/*
 * Check if images np and mask mh are ok and are compatible for DT and RDT
 * computations.
 * Return NPIC_SUCCESS, else error code.
 * set not ok for np on error. Verbose.
*/

int NpicDTCheckData (Npic_image *np, Npic_mask *mh, const char *funcname)
{
    if (NpicImageIsOK (np, funcname) != NPIC_SUCCESS)
        return NPIC_ERR_NOT_OK;
    
    if (NpicMaskIsOK (mh, funcname) != NPIC_SUCCESS) 
        return np->gen.ok = NPIC_ERR_NOT_OK;
       
    if (NpicMaskCompat (mh, np) != NPIC_SUCCESS)
        return np->gen.ok = NpicError (funcname, NPIC_ERR_INCOMPAT, 
                ": dest image and dist mask");
                
    return NPIC_SUCCESS;
}


/*
 * Return the distance type from the property DistanceType of the mask.
 * On error, return NPIC_DIST_NONE. Silent.
*/

Npic_dist_type NpicDTFindDistType (Npic_mask *mh)
{
    int dtype = NPIC_DIST_NONE;
    const char *val;

    if (mh == NULL) return dtype;

    val = NpicMaskGetProp (mh, "DistanceType");
    if      (strcmp (val, "Weighted"        ) == 0) dtype = NPIC_DIST_WEIGHTED;
    else if (strcmp (val, "SquaredEuclidean") == 0) dtype = NPIC_DIST_EUCLID_SQUARED;
    else if (strcmp (val, "CeilEuclidean"   ) == 0) dtype = NPIC_DIST_EUCLID_CEIL;
    else if (strcmp (val, "FloorEulidean"   ) == 0) dtype = NPIC_DIST_EUCLID_FLOOR;

    return dtype;
}