/*
 * 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>
#include <math.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)
{
	/* create file */
	FILE *fp = fopen(file_name, "wb");
	if (!fp)
		abort_("[write_png_file] File %s could not be opened for writing", file_name);


	/* initialize stuff */
	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);


	/* write header */
	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);


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

	png_write_image(png_ptr, row_pointers);


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

	png_write_end(png_ptr, NULL);

        /* cleanup heap allocation */
	for (y=0; y<height; y++)
		free(row_pointers[y]);
	free(row_pointers);

        fclose(fp);
}

void write_pixel(int x, int y, png_byte cr, png_byte cg, png_byte cb){
    png_byte* row = row_pointers[y];
    png_byte* ptr = &(row[x*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*(-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(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=-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{
        printf("tego nie mo�e by�\n");
    }
}

void process_file(void)
{
    int s = 3;

    for (y = 0; y < height; y++) {
        for (x = 0; x < width; x++) {
            double cx = 105.0 * s;
            double cy = 90.0 * s;
            double r = 80.0 * s;
            
            double dx = (double)x - cx;
            double dy = (double)y - cy;
            double dist = sqrt(dx*dx + dy*dy);

            if (dist <= r) {
                double t = dist / r;
                png_byte red   = (png_byte)(255 * (1.0 - t) + 0 * t);
                png_byte green = (png_byte)(255 * (1.0 - t) + 0 * t);
                png_byte blue  = (png_byte)(255 * (1.0 - t) + 128 * t);
                write_pixel(x, y, red, green, blue);
            } else {

                write_pixel(x, y, 255, 165, 0);
            }
        }
    }


    for(int i = 40*s; i < 90*s; i++)
        for(int j = 50*s; j < 130*s; j++)
            if (!(i > 50*s && i < 80*s && j > 60*s && j < 120*s)) 
                write_pixel(i, j, 50, 205, 50);

    // Litera B (belka pionowa i dwa brzuszki)
    for(int i = 110*s; i < 120*s; i++) // Belka
        for(int j = 50*s; j < 130*s; j++) write_pixel(i, j, 50, 205, 50);
    
    for(int i = 120*s; i < 155*s; i++) {
        for(int j = 50*s; j < 60*s; j++) write_pixel(i, j, 50, 205, 50); 
        for(int j = 85*s; j < 95*s; j++) write_pixel(i, j, 50, 205, 50); 
        for(int j = 120*s; j < 130*s; j++) write_pixel(i, j, 50, 205, 50); 
    }
    for(int i = 150*s; i < 160*s; i++) {
        for(int j = 50*s; j < 130*s; j++) write_pixel(i, j, 50, 205, 50); 
    }


    bresenham(40*s, 50*s, 90*s, 50*s, 0,0,0);
    bresenham(90*s, 50*s, 90*s, 130*s, 0,0,0);
    bresenham(40*s, 130*s, 90*s, 130*s, 0,0,0);
    bresenham(40*s, 50*s, 40*s, 130*s, 0,0,0);

    bresenham(50*s, 60*s, 80*s, 60*s, 0,0,0);
    bresenham(80*s, 60*s, 80*s, 120*s, 0,0,0);
    bresenham(50*s, 120*s, 80*s, 120*s, 0,0,0);
    bresenham(50*s, 60*s, 50*s, 120*s, 0,0,0);


    bresenham(110*s, 50*s, 110*s, 130*s, 0,0,0); 
    bresenham(110*s, 50*s, 160*s, 50*s, 0,0,0);
    bresenham(160*s, 50*s, 160*s, 90*s, 0,0,0);
    bresenham(110*s, 90*s, 160*s, 90*s, 0,0,0);
    bresenham(160*s, 90*s, 160*s, 130*s, 0,0,0);
    bresenham(110*s, 130*s, 160*s, 130*s, 0,0,0);
}


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

        return 0;
}