/* LiquidRescaling Library DEMO program
 * Copyright (C) 2007-2009 Carlo Baldassi (the "Author") <carlobaldassi@gmail.com>.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3 dated June, 2007.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/> 
 */

#include <pngwriter.h>
#include <lqr.h>
#include <getopt.h>
#include "liquidrescale.h"

using namespace std;

LqrCarver *carver;

gchar *infile = NULL;
gchar *outfile = NULL;
gchar *pres_infile = NULL;
gchar *pres_outfile = NULL;
gchar *disc_infile = NULL;
gchar *disc_outfile = NULL;
gchar *vmap_infile = NULL;
gchar *vmap_outfile = NULL;
gchar *rigmask_infile = NULL;
gchar *rigmask_outfile = NULL;
gchar *energy_w_outfile = NULL;
gchar *energy_h_outfile = NULL;
gint new_width = 0;
gint new_height = 0;
gfloat rigidity = 0;
gint max_step = 1;
gint pres_strength = 1000;
gint disc_strength = 1000;
LqrResizeOrder res_order = LQR_RES_ORDER_HOR;
gint side_switch_frequency = 0;
gfloat enl_step = 1.5;
gchar *energy_function = NULL;

gfloat new_width_p = 0;
gfloat new_height_p = 0;

gboolean quiet = FALSE;

clock_t clock_start, clock_now;

/*** MAIN ***/

int
main(int argc, char **argv)
{/*{{{*/

    /*** init glib multithreading ***/
    /* (currently only used for
     * cancelling) */
    if (!g_thread_supported()) {
        g_thread_init(NULL);
    }

    /*** read the command line ***/
    TRAP(parse_command_line(argc, argv));

    /*** open input and output files ***/
    pngwriter png(1, 1, 0, outfile);
    png.readfromfile(infile);

    /*** old and new size ***/
    gint old_width = png.getwidth();
    gint old_height = png.getheight();

    if (new_width_p) {
        new_width = (gint) (new_width_p * old_width / 100);
    }
    if (new_height_p) {
        new_height = (gint) (new_height_p * old_height / 100);
    }

    new_width = (new_width ? new_width : old_width);
    new_height = (new_height ? new_height : old_height);

    if (new_width < 2) {
        cerr << "The width should be greater than 2" << endl;
        exit(1);
    }

    if (new_height < 2) {
        cerr << "The height should be greater than 2" << endl;
        exit(1);
    }

    /*** print some information on screen ***/
    if (!quiet) {
        cout << "resizing " << infile << " [" << old_width << "x" << old_height << "] into " <<
            outfile << " [" << new_width << "x" << new_height << "]" << endl << endl << flush;
    }

    if (vmap_infile) {
        info_msg("will read VMap from", vmap_infile);
    }
    if (vmap_outfile) {
        info_msg("will write VMap to", vmap_outfile);
    }

    if ((new_height != old_height) && (new_width != old_width) && (vmap_outfile)) {
        cerr << "Warning: only the last computed visibility map will be written" << endl;
    }

    /*** read and check the feature masks ***/
    pngwriter png_pmask;
    pngwriter png_dmask;

    if (pres_infile) {
        info_msg("will read preservation mask from", pres_infile);
        if (pres_outfile) {
            info_msg("will write preservation mask to", pres_outfile);
            png_pmask.pngwriter_rename(pres_outfile);
        }
        png_pmask.readfromfile(pres_infile);
        if (pres_outfile) {
            if (png_pmask.getwidth() != old_width) {
                cerr << "Fatal error: preservation mask width does not match input file width" << endl;
                cerr << "cannot honour the --pres-out-file option" << endl;
                exit(1);
            }
            if (png_pmask.getheight() != old_height) {
                cerr << "Fatal error: preservation mask height does not match input file height" << endl;
                cerr << "cannot honour the --pres-out-file option" << endl;
                exit(1);
            }
        }
    }

    if (disc_infile) {
        info_msg("will read discard mask from", disc_infile);
        if (disc_outfile) {
            info_msg("will write discrad mask to", disc_outfile);
            png_dmask.pngwriter_rename(disc_outfile);
        }
        png_dmask.readfromfile(disc_infile);
        if (disc_outfile) {
            if (png_dmask.getwidth() != old_width) {
                cerr << "Fatal error: discard mask width does not match input file width" << endl;
                cerr << "cannot honour the --disc-out-file option" << endl;
                exit(1);
            }
            if (png_dmask.getheight() != old_height) {
                cerr << "Fatal error: discard mask height does not match input file height" << endl;
                cerr << "cannot honour the --disc-out-file option" << endl;
                exit(1);
            }
        }
    }

    /*** read and check the rigidity mask ***/
    pngwriter png_rigmask;

    if (rigmask_infile) {
        info_msg("will read rigidity mask from", rigmask_infile);
        if (rigmask_outfile) {
            info_msg("will write rigidity mask to", rigmask_outfile);
            png_pmask.pngwriter_rename(rigmask_outfile);
        }
        png_rigmask.readfromfile(rigmask_infile);
        if (rigmask_outfile) {
            if (png_rigmask.getwidth() != old_width) {
                cerr << "Fatal error: rigidity mask width does not match input file width" << endl;
                cerr << "cannot honour the --rigmask-out-file option" << endl;
                exit(1);
            }
            if (png_rigmask.getheight() != old_height) {
                cerr << "Fatal error: rigidity mask height does not match input file height" << endl;
                cerr << "cannot honour the --rigmask-out-file option" << endl;
                exit(1);
            }
        }
    }

    if (energy_w_outfile) {
        info_msg("will write horizontal energy to", energy_w_outfile);
    }
    if (energy_h_outfile) {
        info_msg("will write vertical energy to", energy_h_outfile);
    }

    /* convert the images into rgb buffers to use them with the library */

    guchar *rgb_buffer;
    guchar *rgb_pres_buffer = NULL;
    guchar *rgb_disc_buffer = NULL;
    guchar *rgb_rigmask_buffer = NULL;

    TRAP_N(rgb_buffer = rgb_buffer_from_image(&png));
    if (pres_infile) {
        TRAP_N(rgb_pres_buffer = rgb_buffer_from_image(&png_pmask));
    }
    if (disc_infile) {
        TRAP_N(rgb_disc_buffer = rgb_buffer_from_image(&png_dmask));
    }
    if (rigmask_infile) {
        TRAP_N(rgb_rigmask_buffer = rgb_buffer_from_image(&png_rigmask));
    }

    if (!quiet) {
        cout << endl;
    }

    /**** (I) GENERATE THE MULTISIZE REPRESENTATION ****/

    /* (I.1) swallow the buffer in a (minimal) LqrCarver object 
     *       (arguments are width, height and number of colour channels) */
    TRAP_N(carver = lqr_carver_new(rgb_buffer, old_width, old_height, 3));

    /* (I.2) if we have to attach other images, we have to do so
     *       immediatley after the carver construction (we might
     *       initialize the carver first, but not load a visibility map)*/
    LqrCarver *pres_carver;
    if (pres_outfile) {
        TRAP_N(pres_carver = lqr_carver_new(rgb_pres_buffer, old_width, old_height, 3));
        TRAP(lqr_carver_attach(carver, pres_carver));
        /* note : this way the rgb_pres_buffer is lost, and we will have
         *        to read it again in order to use it as a bias (this could
         *        be avoided but the code would be harder to read) */
    }

    LqrCarver *disc_carver;
    if (disc_outfile) {
        TRAP_N(disc_carver = lqr_carver_new(rgb_disc_buffer, old_width, old_height, 3));
        TRAP(lqr_carver_attach(carver, disc_carver));
    }

    LqrCarver *rigmask_carver;
    if (rigmask_outfile) {
        TRAP_N(rigmask_carver = lqr_carver_new(rgb_rigmask_buffer, old_width, old_height, 3));
        TRAP(lqr_carver_attach(carver, rigmask_carver));
    }

    /* (I.3) next step depends on whether we have a pre-computed
     *       map to use or not*/
    if (!vmap_infile) {
        /* (I.3a.1) initialize the carver (with default values),
         *          so that we can do the resizing */
        TRAP(lqr_carver_init(carver, max_step, rigidity));

        /* (I.3a.2) add the bias (positive to preserve, negative
         *          to discard) and the rigidity mask*/
        if (pres_infile) {
            TRAP_N(rgb_pres_buffer = rgb_buffer_from_image(&png_pmask));
            TRAP(lqr_carver_bias_add_rgb(carver, rgb_pres_buffer, pres_strength, 3));
        }
        if (disc_infile) {
            TRAP_N(rgb_disc_buffer = rgb_buffer_from_image(&png_dmask));
            TRAP(lqr_carver_bias_add_rgb(carver, rgb_disc_buffer, -disc_strength, 3));
        }
        if (rigmask_infile) {
            TRAP_N(rgb_rigmask_buffer = rgb_buffer_from_image(&png_rigmask));
            TRAP(lqr_carver_rigmask_add_rgb(carver, rgb_rigmask_buffer, 3));
        }

        /* (I.3a.3) set the energy function */
        TRAP(set_energy(carver, energy_function));

        /* (I.3a.4) output the energy function */
        if (energy_w_outfile) {
            TRAP(write_energy(carver, energy_w_outfile, 0));
        }
        if (energy_h_outfile) {
            TRAP(write_energy(carver, energy_h_outfile, 0));
        }

        /* (I.3b.5) set the side switch frequency */
        lqr_carver_set_side_switch_frequency(carver, side_switch_frequency);

        /* (I.3b.6) set the enlargement step */
        TRAP(lqr_carver_set_enl_step(carver, enl_step));
    } else {
        /* (I.3b.1) read a visibility map from a file */
        LqrVMap *vmap;
        vmap = load_vmap_from_file(vmap_infile);
        if (vmap == NULL) {
            cerr << "Unable to load vmap, aborting" << endl;
            exit(1);
        }

        /* (I.3b.2) load it in the carver */
        TRAP(lqr_vmap_load(carver, vmap));
    }

    /* (I.4) if we want to access the visibility maps, we have
     *       to set it in the carver before rescaling occurs */
    if (vmap_outfile) {
        lqr_carver_set_dump_vmaps(carver);
    }

    /**** (II) SET UP THE PROGRESS INDICATOR ****/

    if (!quiet) {
        /* (II.1) generate a progress with default values */
        LqrProgress *progress;
        TRAP_N(progress = lqr_progress_new());

        /* (II.2) set up with custom commands */
        init_progress(progress);

        /* (II.3) attach the progress to out multisize image */
        lqr_carver_set_progress(carver, progress);
    }

    /**** (III) LIQUID RESCALE ****/

    /* (III.1) set the rescaling order */
    lqr_carver_set_resize_order(carver, res_order);

    /* (III.2) catch the INT signal */
    signal(SIGINT, cancel_handler);

    /* (III.3) invoke the rescaling function
     *         this step could be reiterated at wish */
    TRAP(lqr_carver_resize(carver, new_width, new_height));

    /**** (IV) SAVE THE VISIBILITY MAP ****/

    if (vmap_outfile) {
        LqrVMap *vmap;
        TRAP_N(vmap = lqr_vmap_dump(carver));
        TRAP(save_vmap_to_file(vmap, vmap_outfile));
    }
#if 0
    /* alternative way */
    LqrVMapList *vmap_list = lqr_vmap_list_start(carver);
    if (vmap_outfile) {
        TRAP(save_vmap_to_file(lqr_vmap_list_current(vmap_list), vmap_outfile));
        lqr_vmap_list_next(vmap_list);
    }
#endif

    /**** (V) READOUT THE MULTISIZE IMAGE ****/

    /* (V.1) readout the main image */
    TRAP(write_carver_to_image(carver, &png));
    /* (V.2) readout the atteched images */
    LqrCarverList *carver_list = lqr_carver_list_start(carver);
    if (pres_outfile) {
        TRAP(write_carver_to_image(lqr_carver_list_current(carver_list), &png_pmask));
        lqr_carver_list_next(carver_list);
    }
    if (disc_outfile) {
        TRAP(write_carver_to_image(lqr_carver_list_current(carver_list), &png_dmask));
        lqr_carver_list_next(carver_list);
    }
    if (rigmask_outfile) {
        TRAP(write_carver_to_image(lqr_carver_list_current(carver_list), &png_rigmask));
    }

    /**** (VI) DESTROY THE CARVER OBJECT ****/

    lqr_carver_destroy(carver);

    /*** close files (write the images on disk) ***/

    png.close();
    if (pres_outfile) {
        png_pmask.close();
    }
    if (disc_outfile) {
        png_dmask.close();
    }
    if (rigmask_outfile) {
        png_rigmask.close();
    }

    return 0;
}/*}}}*/

/*** PARSE COMMAND LINE ***/

LqrRetVal
parse_command_line(int argc, char **argv)
{/*{{{*/
    int i;
    int c;
    struct option lopts[] = {
        {"file", required_argument, NULL, 'f'},
        {"out-file", required_argument, NULL, 'o'},
        {"width", required_argument, NULL, 'w'},
        {"height", required_argument, NULL, 'h'},
        {"rigidity", required_argument, NULL, 'r'},
        {"max-step", required_argument, NULL, 's'},
        {"pres-file", required_argument, NULL, 'p'},
        {"pres-out-file", required_argument, NULL, 'P'},
        {"pres-strength", required_argument, NULL, 'z'},
        {"disc-file", required_argument, NULL, 'd'},
        {"disc-out-file", required_argument, NULL, 'D'},
        {"disc-strength", required_argument, NULL, 'x'},
        {"rigmask-file", required_argument, NULL, 'k'},
        {"rigmask-out-file", required_argument, NULL, 'K'},
        {"vmap-out-file", required_argument, NULL, 'v'},
        {"vmap-in-file", required_argument, NULL, 'V'},
        {"vertical-first", no_argument, NULL, 't'},
        {"side-switch-frequency", required_argument, NULL, 'n'},
        {"enl-step", required_argument, NULL, 'e'},
        {"energy-function", required_argument, NULL, 'E'},
        {"energy-w-out-file", required_argument, NULL, 'W'},
        {"energy-h-out-file", required_argument, NULL, 'H'},
        {"quiet", no_argument, NULL, 'q'},
        {"help", no_argument, NULL, '#'},
        {NULL, 0, NULL, 0}
    };

    while ((c =
            getopt_long(argc, argv, "f:,o:,w:,h:,r:,s:,p:,P:,z:,d:,D:,x:,k:,K:,v:,V:,t,n:,e:,E:,W:,H:,q", lopts,
                        &i)) != EOF) {
        switch (c) {
            case 'f':
                infile = optarg;
                break;
            case 'o':
                outfile = optarg;
                break;
            case 'w':
                if (optarg[strlen(optarg) - 1] == '%') {
                    new_width_p = atof(optarg);
                } else {
                    new_width = atoi(optarg);
                    new_width_p = 0;
                }
                break;
            case 'h':
                if (optarg[strlen(optarg) - 1] == '%') {
                    new_height_p = atof(optarg);
                } else {
                    new_height = atoi(optarg);
                    new_height_p = 0;
                }
                break;
            case 'r':
                rigidity = atof(optarg);
                break;
            case 's':
                max_step = atoi(optarg);
                break;
            case 'p':
                pres_infile = optarg;
                break;
            case 'P':
                pres_outfile = optarg;
                break;
            case 'z':
                pres_strength = atoi(optarg);
                break;
            case 'd':
                disc_infile = optarg;
                break;
            case 'D':
                disc_outfile = optarg;
                break;
            case 'x':
                disc_strength = atoi(optarg);
                break;
            case 'k':
                rigmask_infile = optarg;
                break;
            case 'K':
                rigmask_outfile = optarg;
                break;
            case 'v':
                vmap_infile = optarg;
                break;
            case 'V':
                vmap_outfile = optarg;
                break;
            case 't':
                res_order = LQR_RES_ORDER_VERT;
                break;
            case 'n':
                side_switch_frequency = atoi(optarg);
                break;
            case 'e':
                enl_step = atof(optarg);
                break;
            case 'E':
                energy_function = optarg;
                break;
            case 'W':
                energy_w_outfile = optarg;
                break;
            case 'H':
                energy_h_outfile = optarg;
                break;
            case 'q':
                quiet = 1;
                break;
            case '#':
                help(argv[0]);
                exit(0);
            default:
                cerr << "Error parsing command line. Use " << argv[0] << " --help for usage instructions." << endl;
                return LQR_ERROR;
        }
    }

    if (!infile) {
        cerr << "Input file missing." << endl;
        return LQR_ERROR;
    }

    if (!outfile) {
        cerr << "Output file missing." << endl;
        return LQR_ERROR;
    }

    if (!new_width && !new_height && !new_width_p && !new_height_p) {
        cerr << "At least one of --width or --height has to be specified (and be different from 0)." << endl;
        return LQR_ERROR;
    }

    if (pres_outfile && !pres_infile) {
        cerr << "Option --pres-out-file can't be used without --pres-in-file." << endl;
        return LQR_ERROR;
    }

    if (disc_outfile && !disc_infile) {
        cerr << "Option --disc-out-file can't be used without --disc-in-file." << endl;
        return LQR_ERROR;
    }

    if (rigmask_outfile && !rigmask_infile) {
        cerr << "Option --rigmask-out-file can't be used without --rigmask-in-file." << endl;
        return LQR_ERROR;
    }

    if (pres_strength < 0) {
        cerr << "Preservation strength cannot be negative." << endl;
        return LQR_ERROR;
    }

    if (disc_strength < 0) {
        cerr << "Discard strength cannot be negative." << endl;
        return LQR_ERROR;
    }

    if (rigidity < 0) {
        cerr << "Rigidity cannot be negative." << endl;
        return LQR_ERROR;
    }

    if (max_step < 0) {
        cerr << "Max step cannot be negative." << endl;
        return LQR_ERROR;
    }

    if ((enl_step <= 1) || (enl_step > 2)) {
        cerr << "Enlargement step must be greater than 1 and not greater than 2." << endl;
        return LQR_ERROR;
    }

    return LQR_OK;
}/*}}}*/

void
help(char *command)
{/*{{{*/
    cout << "Usage: " << command << " -f <file> -o <out-file> [ -w <width> | -h <height> ] [ ... ]" << endl;
    cout << "  Options:" << endl;
    cout << "    -f <file> or --file <file>" << endl;
    cout << "        Specifies input file. Must be in PNG format, in RGB without alpha channel" << endl;
    cout << "    -o <out-file> or --out-file <out-file>" << endl;
    cout << "        Specifies the output file." << endl;
    cout << "    -w <width> or --width <width>" << endl;
    cout << "        The new width. It must be greater than 2." << endl;
    cout << "        If it is 0, or it is not given, the width is unchanged." << endl;
    cout << "        If it is followed by a %, it is interpreted as a percentage with" << endl;
    cout << "        respect to the original width (and needs not to be an integer)." << endl;
    cout << "    -h <height> or --height <height>" << endl;
    cout << "        Same as -w for the height." << endl;
    cout << "    -r <rigidity> or --rigidity < rigidity>" << endl;
    cout << "        Seams rigidity. Any non-negative value is allowed. Defaults to 0." << endl;
    cout << "    -s <max-step> or --max-step <max-step>" << endl;
    cout << "        Maximum seam transversal step. Default value is 1." << endl;
    cout << "    -p <pres-file> or --pres-file <pres-file>" << endl;
    cout << "        File to be used as a mask for features preservation. It must be in the" << endl;
    cout << "        same format as the input file." << endl;
    cout << "    -P <pres-out-file> or --pres-out-file <pres-out-file>" << endl;
    cout << "        If specified, the preservation mask will be rescaled along with the" << endl;
    cout << "        input file, and the output will be written in the specified file." << endl;
    cout << "        The size of the preservation mask has to match that of the original" << endl;
    cout << "        image." << endl;
    cout << "    -z <pres-strength> or --pres-strength <pres-strength>" << endl;
    cout << "        Preservation mask strength. Any integer non-negative value is allowed." << endl;
    cout << "        Defaults to 1000." << endl;
    cout << "    -d <disc-file> or --disc-file <disc-file>" << endl;
    cout << "        File to be used as a mask for features discard. It must be in the" << endl;
    cout << "        same format as the input file." << endl;
    cout << "    -D <disc-out-file> or --disc-out-file <disc-out-file>" << endl;
    cout << "        Same as -P for the discard mask." << endl;
    cout << "    -x <disc-strength> or --disc-strength <disc-strength>" << endl;
    cout << "        Same as -z for the discard mask." << endl;
    cout << "    -v <vmap-file> or --vmap-file <vmap-file>" << endl;
    cout << "        Reads the visibility map from the specified file. The rescaling will fail" << endl;
    cout << "        if it is asked to go beyond the depth of the map." << endl;
    cout << "    -V <vmap-out-file> or --vmap-out-file <vmap-out-file>" << endl;
    cout << "        Writes the visibility map in the specified file. Currently, only the first one." << endl;
    cout << "    -t or --vertical-first" << endl;
    cout << "        Rescale vertically first (instead of horizontally)." << endl;
    cout << "    -n <frequency> or --side-switch-frequency <frequency>" << endl;
    cout << "        Set the number of switches of the side choice for each size modification." << endl;
    cout << "    -e <step> or --enl-step <step>" << endl;
    cout << "        Set the maximum enlargement in a single step." << endl;
    cout << "        It must be greater than 1 and not greater than 2 (default = 1.5)" << endl;
    cout << "    -E <energy-function> or --energy-function <energy-function>" << endl;
    cout << "        Possible values are: xabs, sumabs, norm, xsobel, sobel" << endl;
    cout << "    -W <energy-w-out-file> or --energy-w-out-file <energy-w-out-file>" << endl;
    cout << "        Writes the energy map for horizontal scalings in the specified file" << endl;
    cout << "    -H <energy-h-out-file> or --energy-h-out-file <energy-h-out-file>" << endl;
    cout << "        Writes the energy map for vertical scalings in the specified file" << endl;
    cout << "    -q or --quiet" << endl;
    cout << "        Quiet mode." << endl;
    cout << "    --help" << endl;
    cout << "        This help." << endl;
}/*}}}*/

/*** AUXILIARY I/O FUNCTIONS ***/

/* convert the image in the right format */
guchar *
rgb_buffer_from_image(pngwriter *png)
{/*{{{*/
    gint x, y, k, channels;
    gint w, h;
    guchar *buffer;

    /* get info from the image */
    w = png->getwidth();
    h = png->getheight();
    channels = 3;                       // we assume an RGB image here 

    /* allocate memory to store w * h * channels unsigned chars */
    buffer = g_try_new(guchar, channels * w * h);
    g_assert(buffer != NULL);

    /* start iteration (always y first, then x, then colours) */
    for (y = 0; y < h; y++) {
        for (x = 0; x < w; x++) {
            for (k = 0; k < channels; k++) {
                /* read the image channel k at position x,y */
                buffer[(y * w + x) * channels + k] = (guchar) (png->dread(x + 1, y + 1, k + 1) * 255);
                /* note : the x+1,y+1,k+1 on the right side are
                 *        specific the pngwriter library */
            }
        }
    }

    return buffer;
}/*}}}*/

/* readout the multizie image */
LqrRetVal
write_carver_to_image(LqrCarver *r, pngwriter *png)
{/*{{{*/
    gint x, y;
    guchar *rgb;
    gdouble red, green, blue;
    gint w, h;

    /* make sure the image is RGB */
    LQR_CATCH_F(lqr_carver_get_channels(r) == 3);

    /* resize the image canvas as needed to
     * fit for the new size */
    w = lqr_carver_get_width(r);
    h = lqr_carver_get_height(r);
    png->resize(w, h);

    /* initialize image reading */
    lqr_carver_scan_reset(r);

    /* readout (no need to init rgb) */
    while (lqr_carver_scan(r, &x, &y, &rgb)) {
        /* convert the output into doubles */
        red = (gdouble) rgb[0] / 255;
        green = (gdouble) rgb[1] / 255;
        blue = (gdouble) rgb[2] / 255;

        /* plot (pngwriter's coordinates start from 1,1) */
        png->plot(x + 1, y + 1, red, green, blue);
    }

    return LQR_OK;
}/*}}}*/

/*** ENERGY FUNCTIONS ***/

/* define custom energy function: sobelx */
gfloat
sobelx(gint x, gint y, gint w, gint h, LqrReadingWindow *rw, gpointer extra_data)
{/*{{{*/
    gint i, j;
    gdouble e = 0;
    gdouble k[3][3] = { {0.125, 0.25, 0.125}, {0, 0, 0}, {-0.125, -0.25, -0.125} };

    for (i = -1; i <= 1; i++) {
        for (j = -1; j <= 1; j++) {
            e += k[i + 1][j + 1] * lqr_rwindow_read(rw, i, j, 0);
        }
    }
    return (gfloat) fabs(e);
}/*}}}*/

/* define custom energy function: sobel */
gfloat
sobel(gint x, gint y, gint w, gint h, LqrReadingWindow *rw, gpointer extra_data)
{/*{{{*/
    gint i, j;
    gdouble ex = 0;
    gdouble ey = 0;
    gdouble k[3][3] = { {0.125, 0.25, 0.125}, {0, 0, 0}, {-0.125, -0.25, -0.125} };

    for (i = -1; i <= 1; i++) {
        for (j = -1; j <= 1; j++) {
            ex += k[i + 1][j + 1] * lqr_rwindow_read(rw, i, j, 0);
            ey += k[j + 1][i + 1] * lqr_rwindow_read(rw, i, j, 0);
        }
    }
    return (gfloat) (sqrt(ex * ex + ey * ey));
}/*}}}*/

/* set the energy function */
LqrRetVal
set_energy(LqrCarver *carver, gchar *energy_function)
{/*{{{*/
    if (energy_function == NULL) {
        return LQR_OK;
    } else if (g_strcmp0(energy_function, "xabs") == 0) {
        LQR_CATCH(lqr_carver_set_energy_function_builtin(carver, LQR_EF_GRAD_XABS));
    } else if (g_strcmp0(energy_function, "sumabs") == 0) {
        LQR_CATCH(lqr_carver_set_energy_function_builtin(carver, LQR_EF_GRAD_SUMABS));
    } else if (g_strcmp0(energy_function, "norm") == 0) {
        LQR_CATCH(lqr_carver_set_energy_function_builtin(carver, LQR_EF_GRAD_NORM));
    } else if (g_strcmp0(energy_function, "sobelx") == 0) {
        LQR_CATCH(lqr_carver_set_energy_function(carver, sobelx, 1, LQR_ER_BRIGHTNESS, NULL));
    } else if (g_strcmp0(energy_function, "sobel") == 0) {
        LQR_CATCH(lqr_carver_set_energy_function(carver, sobel, 1, LQR_ER_BRIGHTNESS, NULL));
    } else {
        cerr << "Unknown energy function: " << energy_function << endl;
        exit(1);
    }
    return LQR_OK;
}/*}}}*/

/* write out the energy */
LqrRetVal
write_energy(LqrCarver *carver, gchar *energy_outfile, gint orientation)
{/*{{{*/
    gfloat *nrg_buffer;

    pngwriter png_nrg;

    png_nrg.pngwriter_rename(energy_outfile);

    gint x, y;
    gfloat en;
    gdouble red, green, blue;

    gint w = lqr_carver_get_width(carver);
    gint h = lqr_carver_get_height(carver);

    png_nrg.resize(w, h);

    LQR_CATCH_MEM(nrg_buffer = g_try_new0(gfloat, w * h));
    LQR_CATCH(lqr_carver_get_energy(carver, nrg_buffer, orientation));

    for (y = 0; y < h; y++) {
        for (x = 0; x < w; x++) {
            en = nrg_buffer[y * w + x];
            red = (gdouble) en;
            green = (gdouble) en;
            blue = (gdouble) en;

            /* plot (pngwriter's coordinates start from 1,1) */
            png_nrg.plot(x + 1, y + 1, red, green, blue);
        }
    }

    g_free(nrg_buffer);

    png_nrg.close();

    return LQR_OK;
}/*}}}*/

/*** PROGRESS INDICATOR ***/

/* set up the progress functions */
LqrRetVal
my_progress_init(const gchar *message)
{/*{{{*/
    printf("%s --------------------  0.00%% (00:00.00)", message);
    fflush(stdout);
    clock_start = clock();
    return LQR_OK;
}/*}}}*/

LqrRetVal
my_progress_update(gdouble percentage)
{/*{{{*/
    gint i;
    gfloat p;
    for (i = 0; i < 38; i++) {
        printf("\b");
    }
    for (i = 0; i < 20 * percentage; i++) {
        printf("*");
    }
    for (; i < 20; i++) {
        printf("-");
    }
    p = 100 * percentage;
    printf(" %s%.2f%%", p < 10 ? " " : "", p);

    gfloat t;
    clock_now = clock();
    t = (gfloat) (clock_now - clock_start) / CLOCKS_PER_SEC;

    i = (gint) t;

    gint min, sec, cent;

    min = i / 60;
    sec = i % 60;
    cent = (gint) ((t - i) * 100);
    printf(" (%.2i:%.2i.%.2i)", min, sec, cent);
    fflush(stdout);
    return LQR_OK;
}/*}}}*/

LqrRetVal
my_progress_end(const gchar *message)
{/*{{{*/
    gint i;
    for (i = 0; i < 38; i++) {
        printf("\b");
    }
    printf("********************   %s", message);

    gfloat t;
    clock_now = clock();
    t = (gfloat) (clock_now - clock_start) / CLOCKS_PER_SEC;

    i = (gint) t;

    gint min, sec, cent;

    min = i / 60;
    sec = i % 60;
    cent = (gint) ((t - i) * 100);
    printf(" (%.2i:%.2i.%.2i)\n", min, sec, cent);

    fflush(stdout);
    return LQR_OK;
}/*}}}*/

/* setup the progress machinery */
void
init_progress(LqrProgress * progress)
{/*{{{*/
    lqr_progress_set_init(progress, my_progress_init);
    lqr_progress_set_update(progress, my_progress_update);
    lqr_progress_set_end(progress, my_progress_end);
    lqr_progress_set_init_width_message(progress, "Resizing width  :");
    lqr_progress_set_init_height_message(progress, "Resizing height :");
    lqr_progress_set_end_width_message(progress, "done");
    lqr_progress_set_end_height_message(progress, "done");
    lqr_progress_set_update_step(progress, 0.01);
}/*}}}*/

/*** VISIBILTY MAPS ***/

/* convert a visibility map in binary and stores it in a file */
LqrRetVal
save_vmap_to_file(LqrVMap *vmap, gchar *name)
{/*{{{*/
    FILE *sink;
    gint *buffer;
    gint width, height, depth, orientation;
    gint y, x;
    gint32 vs;

    buffer = lqr_vmap_get_data(vmap);
    width = lqr_vmap_get_width(vmap);
    height = lqr_vmap_get_height(vmap);
    depth = lqr_vmap_get_depth(vmap);
    orientation = lqr_vmap_get_orientation(vmap);

    /* open file */
    if ((sink = fopen(name, "wb")) == NULL) {
        cerr << "error opening outfile : " << name << endl;
        return LQR_ERROR;
    }

    /* VMAP : filtype */
    fprintf(sink, "VMAP[");

    /* HEAD : the header */
    fprintf(sink, "HEAD[");

    fprintf(sink, "[width=%i]", width);
    fprintf(sink, "[height=%i]", height);
    fprintf(sink, "[orientation=%i]", orientation);
    fprintf(sink, "[depth=%i]", depth);
    fprintf(sink, "[comment=()]");

    /* close HEAD */
    fprintf(sink, "]");

    /* BODY : the data */
    fprintf(sink, "BODY[");

    /* vmap is a buffer of gint's */
    for (y = 0; y < height; y++) {
        for (x = 0; x < width; x++) {
            vs = buffer[y * width + x];
            fprintf(sink, "%c%c%c%c", (vs >> 24) & 0xFF, ((vs >> 16) & 0xFF), ((vs >> 8) & 0xFF), vs & 0xFF);
        }
    }
    /* close BODY */
    fprintf(sink, "]");

    /* close VMAP */
    fprintf(sink, "]");

    /* close file */
    fclose(sink);

    return LQR_OK;
}/*}}}*/

/* reads a binary file and converts it into a visibility map */
LqrVMap *
load_vmap_from_file(gchar *name)
{/*{{{*/
    FILE *input;
    gint x, y, z0;
    gint w, h, depth, orientation;
    gint c, i;
    guchar i1, i2, i3, i4;
    gint32 vs;
    gboolean w_ok, h_ok, d_ok, o_ok;
    gchar read_buffer[RBS];
    gchar read_tag[RBS];
    gint *buffer;
    LqrVMap *vmap;

    /* flags */
    w_ok = h_ok = d_ok = o_ok = FALSE;

    w = h = depth = orientation = 0;

    /* open file */
    CHECK_OR_N(((input = fopen(name, "rb")) != NULL), "can't open vmap file");

    /* read filetype */
    CHECK_OR_N(fscanf(input, "VMAP[") != EOF, "not a VMAP file");

    /* read the header */
    CHECK_OR_N(fscanf(input, "HEAD[") != EOF, "missing vmap header");

    /* scan the header */
    while (1) {
        CHECK_OR_N((c = getc(input)) != EOF, "corrupted vmap header");
        if (c == ']') {
            /* the header has ended */
            break;
        }
        ungetc(c, input);

        /* start reading a tag */
        CHECK_OR_N(fscanf(input, "[") != EOF, "corrupted vmap header");

        /* start reading the tag name */
        i = 0;
        while (((c = getc(input)) != EOF) && (i < RBS)) {
            if (c == '=') {
                /* the tag name has ended */
                break;
            }
            read_tag[i++] = c;
        }
        CHECK_OR_N(i < RBS, "vmap tag name too long");

        read_tag[i] = '\0';

        /* start reading the tag content */
        i = 0;
        while (((c = getc(input)) != EOF) && (i < RBS)) {
            if (c == ']') {
                /* the tag has ended */
                break;
            }
            read_buffer[i++] = c;
        }
        CHECK_OR_N(i < RBS, "tag content too long");
        read_buffer[i] = '\0';

        /* set the corresponding variable and the flag */
        if (strncmp(read_tag, "width", RBS) == 0) {
            w = atoi(read_buffer);
            w_ok = TRUE;
        } else if (strncmp(read_tag, "height", RBS) == 0) {
            h = atoi(read_buffer);
            h_ok = TRUE;
        } else if (strncmp(read_tag, "depth", RBS) == 0) {
            depth = atoi(read_buffer);
            d_ok = TRUE;
        } else if (strncmp(read_tag, "orientation", RBS) == 0) {
            orientation = atoi(read_buffer);
            o_ok = TRUE;
        } else if (strncmp(read_tag, "comment", RBS) == 0) {
            /* discard comments */
        } else {
            cerr << "warning : unknown tag : " << read_tag << endl;
        }
    }

    /* check if all the needed quantities are there */
    CHECK_OR_N(w_ok && h_ok && d_ok && o_ok, "missing vmap tags");

    /* start reading the data */
    CHECK_OR_N(fscanf(input, "BODY[") != EOF, "missing vmap body");

    /* allocate memory for the vmap buffer */
    buffer = g_try_new0(gint, w * h);
    if (buffer == NULL) {
        return NULL;
    }

    /* scan the data */
    y = x = 0;
    while ((y < h) && ((c = getc(input)) != EOF)) {
        ungetc(c, input);

        /* read a 32 bit integer */
        CHECK_OR_N(fscanf(input, "%c%c%c%c", &i1, &i2, &i3, &i4) == 4, "vmap data corrupted");
        vs = i4 + (i3 << 8) + (i2 << 16) + (i1 << 24);

        /* set it in the buffer */
        z0 = y * w + x;
        buffer[z0] = vs;

        /* update the coordinates */
        x++;
        if (x == w) {
            x = 0;
            y++;
        }
    }

    /* test if the amount of data read is correct */
    CHECK_OR_N((x == 0) && (y == h), "vmap data corrupted");

    /* end reading the data */
    CHECK_OR_N(fscanf(input, "]") != EOF, "unterminated vmap body");

    /* end reading the vmap file */
    CHECK_OR_N(fscanf(input, "]") != EOF, "unterminated vmap file");

    /* create the vmap object with all the data aquired */
    vmap = lqr_vmap_new(buffer, w, h, depth, orientation);
    if (vmap == NULL) {
        return NULL;
    }

    return vmap;
}/*}}}*/

/*** EXTRA ***/

void
info_msg(const gchar *msg, const gchar *name)
{/*{{{*/
    if (!quiet) {
        cout << "  + " << msg << " " << name << endl << flush;
    }
}/*}}}*/

void
cancel_handler(int signum)
{/*{{{*/
    printf("\n");
    fflush(stdout);
    /* We must cancel the computation
     * from a different thread */
    g_thread_create(cancel_thread, (gpointer) carver, FALSE, NULL);
}/*}}}*/

gpointer
cancel_thread(gpointer data)
{/*{{{*/
    lqr_carver_cancel((LqrCarver *) data);
    return NULL;
}/*}}}*/