/* The Analysis & Resynthesis Sound Spectrograph
Copyright (C) 2005-2008 Michel Rouzic

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; either version 2
of the License, or (at your option) any later version.

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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.*/

#include "image_io.h"

double **bmp_in(FILE *bmpfile, int32_t *y, int32_t *x)
{
        int32_t        iy, ix, ic;             // various iterators
        int32_t offset;
        double **image;
        uint8_t        zerobytes, val;
        #ifdef DEBUG
        printf("bmp_in...\n");
        #endif

        if (fread_le_short(bmpfile) != 19778)          // "BM" format tag check
        {
                fprintf(stderr, "This file is not in BMP format\n");
                win_return();
                exit(EXIT_FAILURE);
        }

        fseek(bmpfile, 8, SEEK_CUR);           // skipping useless tags
        offset = fread_le_word(bmpfile) - 54;  // header offset
        fseek(bmpfile, 4, SEEK_CUR);           // skipping useless tags
        *x = fread_le_word(bmpfile);
        *y = fread_le_word(bmpfile);
        fseek(bmpfile, 2, SEEK_CUR);           // skipping useless tags

        if (fread_le_short(bmpfile) != 24)     // Only format supported
        {
                fprintf(stderr, "Wrong BMP format, BMP images must be in 24-bit colour\n");
                win_return();
                exit(EXIT_FAILURE);
        }

        fseek(bmpfile, 24+offset, SEEK_CUR);   // skipping useless tags

        image = malloc (*y * sizeof(double));  // image allocation
        for (iy=0; iy<*y; iy++)
                image[iy]=calloc (*x, sizeof(double));


        zerobytes = 4 - ((*x*3) & 3);
        if (zerobytes==4)
                zerobytes = 0;

        for (iy=*y-1; iy!=-1; iy--)            // backwards reading
        {
                for (ix=0; ix<*x; ix++)
                {
                        for (ic=2;ic!=-1;ic--)
                        {
                                fread(&val, 1, 1, bmpfile);
                                image[iy][ix] += (double) val * (1.0/(255.0 * 3.0));        // Conversion to grey by averaging the three channels
                        }
                }

                fseek(bmpfile, zerobytes, SEEK_CUR);  // skipping padding bytes
        }

        fclose(bmpfile);
        return image;
}

void bmp_out(FILE *bmpfile, double **image, int32_t y, int32_t x)
{
        int32_t        i, iy, ix, ic;                  // various iterators
        int32_t        filesize, imagesize;
        uint8_t        zerobytes, val, zero=0;
        double vald;

        #ifdef DEBUG
        printf("bmp_out...\n");
        #endif

        zerobytes = 4 - ((x*3) & 3);           // computation of zero bytes
        if (zerobytes==4)
                zerobytes = 0;

        //********Tags********

        filesize = 56 + ((x*3)+zerobytes) * y;
        imagesize = 2 + ((x*3)+zerobytes) * y;

        fwrite_le_short(19778, bmpfile);
        fwrite_le_word(filesize, bmpfile);
        fwrite_le_word(0, bmpfile);
        fwrite_le_word(54, bmpfile);
        fwrite_le_word(40, bmpfile);
        fwrite_le_word(x, bmpfile);
        fwrite_le_word(y, bmpfile);
        fwrite_le_short(1, bmpfile);
        fwrite_le_word(24, bmpfile);
        fwrite_le_short(0, bmpfile);
        fwrite_le_word(imagesize, bmpfile);
        fwrite_le_word(2834, bmpfile);
        fwrite_le_word(2834, bmpfile);
        fwrite_le_word(0, bmpfile);
        fwrite_le_word(0, bmpfile);
        //--------Tags--------

        for (iy=y-1; iy!=-1; iy--)             // backwards writing
        {
                for (ix=0; ix<x; ix++)
                {
                        vald = image[iy][ix] * 255.0;

                        if (vald > 255.0)
                                vald = 255.0;

                        if (vald < 0.0)
                                vald = 0.0;

                        val = vald;

                        for (ic=2; ic!=-1; ic--)
                                fwrite(&val, 1, 1, bmpfile);
                }
                for (i=0; i<zerobytes; i++)
                        fwrite(&zero, 1, 1, bmpfile);        // write padding bytes
        }

        fwrite_le_short(0, bmpfile);

        fclose(bmpfile);

        #ifdef DEBUG
        printf("Image size : %dx%d\n", x, y);
        #endif
}