/*
 * Copyright 2002-2008 Guillaume Cottenceau, 2015 Aleksander Denisiuk
 *
 * This software may be freely redistributed under the terms
 * of the X11 license.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>

#define PNG_DEBUG 3
#include <png.h>


#define OUT_FILE "initials.png"
#define WIDTH 600
#define HEIGHT 600
#define COLOR_TYPE PNG_COLOR_TYPE_RGB
#define BIT_DEPTH 8


void abort_(const char * s, ...)
{
 va_list args;
 va_start(args, s);
 vfprintf(stderr, s, args);
 fprintf(stderr, "\n");
 va_end(args);
 abort();
}

int x, y;

int width, height;
png_byte color_type;
png_byte bit_depth;

png_structp png_ptr;
png_infop info_ptr;
int number_of_passes;
png_bytep * row_pointers;

void create_png_file()
{
 width = WIDTH;
 height = HEIGHT;
        bit_depth = BIT_DEPTH;
        color_type = COLOR_TYPE;

 row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * height);
 for (y=0; y<height; y++)
  row_pointers[y] = (png_byte*) malloc(width*bit_depth*3);


}


void write_png_file(char* file_name)
{
 FILE *fp = fopen(file_name, "wb");
 if (!fp)
  abort_("[write_png_file] File %s could not be opened for writing", file_name);



 png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

 if (!png_ptr)
  abort_("[write_png_file] png_create_write_struct failed");

 info_ptr = png_create_info_struct(png_ptr);
 if (!info_ptr)
  abort_("[write_png_file] png_create_info_struct failed");

 if (setjmp(png_jmpbuf(png_ptr)))
  abort_("[write_png_file] Error during init_io");

 png_init_io(png_ptr, fp);



 if (setjmp(png_jmpbuf(png_ptr)))
  abort_("[write_png_file] Error during writing header");

 png_set_IHDR(png_ptr, info_ptr, width, height,
       bit_depth, color_type, PNG_INTERLACE_NONE,
       PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);

 png_write_info(png_ptr, info_ptr);



 if (setjmp(png_jmpbuf(png_ptr)))
  abort_("[write_png_file] Error during writing bytes");

 png_write_image(png_ptr, row_pointers);



 if (setjmp(png_jmpbuf(png_ptr)))
  abort_("[write_png_file] Error during end of write");

 png_write_end(png_ptr, NULL);


 for (y=0; y<height; y++)
  free(row_pointers[y]);
 free(row_pointers);

        fclose(fp);
}

void write_pixel(int i, int y, png_byte cr, png_byte cg, png_byte cb)
{
    png_byte* row = row_pointers[y];
    png_byte* ptr = &(row[i*3]);
    ptr[0] = cr;
    ptr[1] = cg;
    ptr[2] = cb;

}

void bresenham(int i1, int j1, int i2, int j2,
               png_byte cr, png_byte cg, png_byte cb)
{
    int m, b, j, P, i;

    if(i2>i1 && j2>=j1 && j2-j1<=i2-i1){
        printf("przypadek 1\n");
        m = 2*(j2-j1);
        b = 0;
        write_pixel(i1, j1, cr, cg, cb);
        j = j1;
        P = i2-i1;
        for(i = i1+1; i<=i2; i++){
            b = b+m;
            if(b>P){
                j = j+1;
                b = b-2*P;
            }
            write_pixel(i, j, cr, cg, cb);
        }
    }
    else if(i2>i1 && -j2>=-j1 && -j2+j1<=i2-i1){
        printf("przypadek 2\n");
        m = 2*(j1-j2);
    b = 0;
    write_pixel(i1, j1, cr, cg, cb);
    j = j1;
    P = i2-i1;

    for(i = i1+1; i<=i2; i++){
        b = b + m;
        if(b > P){
            j = j - 1;
            b = b - 2*P;
        }
        write_pixel(i, j, cr, cg, cb);
        }
    }
    else if(j2>j1 && i2>=i1 && i2-i1<=j2-j1){
        printf("przypadek 3\n");
         m = 2*(i2-i1);
    b = 0;
    write_pixel(i1, j1, cr, cg, cb);
    i = i1;
    P = j2-j1;

    for(j = j1+1; j<=j2; j++){
        b = b + m;
        if(b > P){
            i = i + 1;
            b = b - 2*P;
        }
        write_pixel(i, j, cr, cg, cb);
    }
    }
    else if(-j2>-j1 && i2>=i1 && i2-i1<=j2+j1){
        printf("przypadek 4\n");
         m = 2*(i2-i1);
    b = 0;
    write_pixel(i1, j1, cr, cg, cb);
    i = i1;
    P = j1-j2;

    for(j = j1-1; j>=j2; j--){
        b = b + m;
        if(b > P){
            i = i + 1;
            b = b - 2*P;
        }
        write_pixel(i, j, cr, cg, cb);
    }
    }else{
        printf("nigdy tego nie zobacze\n");
    }
}

void draw_circle(int xc, int yc, int r, int cr, int cg, int cb)
{
    int a = r;
    int b = r;

    int i = 0;
    int j = b;

    int a2 = a * a;
    int b2 = b * b;

    int f = 4 * b2 - 4 * a2 * b + a2;

    int x;

    #define FILL_LINE(y_offset, x_left, x_right) \
        for (x = (x_left); x <= (x_right); x++) \
            write_pixel(x, yc + (y_offset), cr, cg, cb);


    FILL_LINE(j, xc - i, xc + i);
    FILL_LINE(-j, xc - i, xc + i);

    while (b2 * i < a2 * j)
    {
        if (f > 0)
        {
            f = f + 8 * b2 * i - 8 * a2 * j + 12 * b2 + 8 * a2;
            j = j - 1;
        }
        else
        {
            f = f + 8 * b2 * i + 12 * b2;
        }

        i = i + 1;


        FILL_LINE(j, xc - i, xc + i);
        FILL_LINE(-j, xc - i, xc + i);
    }

    #undef FILL_LINE
}

void process_file(void)
{
 for (y=0; y<height; y++) {
  png_byte* row = row_pointers[y];
  for (x=0; x<width; x++) {
   png_byte* ptr = &(row[x*3]);
   ptr[0] = 0;
   ptr[1] = ptr[2] = 255;
  }
 }

 draw_circle(300, 300, 150, 0, 0, 0);

png_byte r = 255, g = 255, b = 255;

    bresenham(100, 200, 150, 450, r, g, b);
    bresenham(150, 450, 200, 300, r, g, b);
    bresenham(200, 300, 250, 450, r, g, b);
    bresenham(250, 450, 300, 200, r, g, b);
    bresenham(130, 200, 170, 400, r, g, b); 
    bresenham(170, 400, 200, 330, r, g, b);
    bresenham(200, 330, 230, 400, r, g, b);
    bresenham(230, 400, 270, 200, r, g, b);
    bresenham(100, 200, 130, 200, r, g, b);
    bresenham(270, 200, 300, 200, r, g, b);


    bresenham(350, 200, 450, 200, r, g, b);
    bresenham(350, 230, 420, 230, r, g, b);
    bresenham(350, 200, 350, 300, r, g, b);
    bresenham(380, 230, 380, 270, r, g, b);
    bresenham(350, 300, 450, 300, r, g, b);
    bresenham(380, 270, 450, 270, r, g, b);
    bresenham(450, 270, 450, 400, r, g, b);
    bresenham(420, 300, 420, 370, r, g, b); 
    bresenham(350, 400, 450, 400, r, g, b);
    bresenham(380, 370, 450, 370, r, g, b);
    bresenham(350, 370, 350, 400, r, g, b);
    bresenham(350, 370, 380, 370, r, g, b);
    bresenham(450, 200, 450, 230, r, g, b);

int main(int argc, char **argv)
{
 create_png_file();
 process_file();
 write_png_file(OUT_FILE);

        return 0;
}