/* ============================================================================
 * Freetype GL - A C OpenGL Freetype engine
 * Platform:    Any
 * WWW:         https://github.com/rougier/freetype-gl
 * ----------------------------------------------------------------------------
 * Copyright 2011,2012 Nicolas P. Rougier. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY NICOLAS P. ROUGIER ''AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL NICOLAS P. ROUGIER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are
 * those of the authors and should not be interpreted as representing official
 * policies, either expressed or implied, of Nicolas P. Rougier.
 * ============================================================================
 */
#include <float.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "edtaa3func.h"


double *
make_distance_mapd( double *data, unsigned int width, unsigned int height )
{
    short * xdist = (short *)  malloc( width * height * sizeof(short) );
    short * ydist = (short *)  malloc( width * height * sizeof(short) );
    double * gx   = (double *) calloc( width * height, sizeof(double) );
    double * gy      = (double *) calloc( width * height, sizeof(double) );
    double * outside = (double *) calloc( width * height, sizeof(double) );
    double * inside  = (double *) calloc( width * height, sizeof(double) );
    double vmin = DBL_MAX;
    unsigned int i;

    //@appamics.CB: extra checks
    assert(xdist);
    assert(ydist);
    assert(gx);
    assert(gy);
    assert(outside);
    assert(inside);

    // Compute outside = edtaa3(bitmap); % Transform background (0's)
    computegradient( data, width, height, gx, gy);
    edtaa3(data, gx, gy, width, height, xdist, ydist, outside);
    for( i=0; i<width*height; ++i)
        if( outside[i] < 0.0 )
            outside[i] = 0.0;

    // Compute inside = edtaa3(1-bitmap); % Transform foreground (1's)
    memset( gx, 0, sizeof(double)*width*height );
    memset( gy, 0, sizeof(double)*width*height );
    for( i=0; i<width*height; ++i)
        data[i] = 1 - data[i];
    computegradient( data, width, height, gx, gy );
    edtaa3( data, gx, gy, width, height, xdist, ydist, inside );
    for( i=0; i<width*height; ++i )
        if( inside[i] < 0 )
            inside[i] = 0.0;

    // distmap = outside - inside; % Bipolar distance field
    for( i=0; i<width*height; ++i)
    {
        outside[i] -= inside[i];
        if( outside[i] < vmin )
            vmin = outside[i];
    }

    vmin = fabs(vmin);

    for( i=0; i<width*height; ++i)
    {
        double v = outside[i];
        if     ( v < -vmin) outside[i] = -vmin;
        else if( v > +vmin) outside[i] = +vmin;
        data[i] = (outside[i]+vmin)/(2*vmin);
    }

    free( xdist );
    free( ydist );
    free( gx );
    free( gy );
    free( outside );
    free( inside );
    return data;
}

unsigned char *
make_distance_mapb( unsigned char *img,
                    unsigned int width, unsigned int height )
{
    double * data    = (double *) calloc( width * height, sizeof(double) );
    unsigned char *out = (unsigned char *) malloc( width * height * sizeof(unsigned char) );
    unsigned int i;

    //@appamics.CB: extra checks
    assert(data);
    assert(out);

    // find minimimum and maximum values
    double img_min = DBL_MAX;
    double img_max = DBL_MIN;

    for( i=0; i<width*height; ++i)
    {
        double v = img[i];
        data[i] = v;
        if (v > img_max)
            img_max = v;
        if (v < img_min)
            img_min = v;
    }

    // Map values from 0 - 255 to 0.0 - 1.0
    for( i=0; i<width*height; ++i)
        data[i] = (img[i]-img_min)/img_max;

    data = make_distance_mapd(data, width, height);

    // map values from 0.0 - 1.0 to 0 - 255
    for( i=0; i<width*height; ++i)
        out[i] = (unsigned char)(255*(1-data[i]));

    free( data );

    return out;
}