/*
* 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)
{
	/* 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 moze byc!\n");
    }

}
void write8pixel(int x, int y, png_byte cr, png_byte cg, png_byte cb){
    write_pixel(x+WIDTH/2,y+HEIGHT/2,cr,cg,cb);
    write_pixel(-x+WIDTH/2,y+HEIGHT/2,cr,cg,cb);
    write_pixel(x+WIDTH/2,-y+HEIGHT/2,cr,cg,cb);
    write_pixel(-x+WIDTH/2,-y+HEIGHT/2,cr,cg,cb);
    write_pixel(y+WIDTH/2,x+HEIGHT/2,cr,cg,cb);
    write_pixel(-y+WIDTH/2,x+HEIGHT/2,cr,cg,cb);
    write_pixel(y+WIDTH/2,-x+HEIGHT/2,cr,cg,cb);
    write_pixel(-y+WIDTH/2,-x+HEIGHT/2,cr,cg,cb);

}

void circle(int R,png_byte cr, png_byte cg, png_byte cb){
    int i,j,f;
    i=0;
    j=R;
    f=5-4*R;
    write8pixel(i,j,cr,cg,cb);
    while(i<j){
        if(f>0){
            f=f+8*i-8*j+20;
            j=j-1;
        }
        else{
            f = f+8*i+12;
        }
        i = i+1;
        write8pixel(i,j,cr,cg,cb);
    }

}

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;
		}
	}

	bresenham(170, 200, 260, 200, 0, 0, 0);
	bresenham(260, 200, 261, 230, 0, 0, 0);
	bresenham(201, 230, 261, 230, 0, 0, 0);
	bresenham(195, 290, 201, 230, 0, 0, 0);
	bresenham(195, 290, 255, 310, 0, 0, 0);
	bresenham(245, 400, 255, 310, 0, 0, 0);
	bresenham(155, 400, 245, 400, 0, 0, 0);
	bresenham(154, 370, 155, 400, 0, 0, 0);
	bresenham(154, 370, 214, 370, 0, 0, 0);
	bresenham(214, 370, 220, 310, 0, 0, 0);
	bresenham(160, 290, 220, 310, 0, 0, 0);
	bresenham(160, 290, 170, 200, 0, 0, 0);

	bresenham(320, 200, 350, 200, 0, 0, 0);
	bresenham(320, 200, 325, 400, 0, 0, 0);
	bresenham(325, 400, 355, 400, 0, 0, 0);
	bresenham(350, 200, 352, 280, 0, 0, 0);
	bresenham(352, 280, 410, 200, 0, 0, 0);
	bresenham(410, 200, 440, 200, 0, 0, 0);
	bresenham(353, 310, 440, 200, 0, 0, 0);
	bresenham(353, 310, 440, 400, 0, 0, 0);
	bresenham(410, 400, 440, 400, 0, 0, 0);
	bresenham(354, 340, 410, 400, 0, 0, 0);
	bresenham(354, 340, 355, 400, 0, 0, 0);


	circle(200, 0, 0, 0);
}


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

        return 0;
}