/*
 * 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)
{
    if (i1 > i2) {
        int tempI = i1; i1 = i2; i2 = tempI;
        int tempJ = j1; j1 = j2; j2 = tempJ;
    }

    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 byc nie moze!\n");
    }
}

void circle_pixels(int is, int js, int i, int j, png_byte cr, png_byte cg, png_byte cb)
{
    write_pixel(is + i, js + j, cr, cg, cb);
    write_pixel(is + j, js + i, cr, cg, cb);
    write_pixel(is + i, js - j, cr, cg, cb);
    write_pixel(is + j, js - i, cr, cg, cb);

    write_pixel(is - i, js + j, cr, cg, cb);
    write_pixel(is - j, js + i, cr, cg, cb);
    write_pixel(is - i, js - j, cr, cg, cb);
    write_pixel(is - j, js - i, cr, cg, cb);
}

void circle(int is, int js, int R, png_byte cr, png_byte cg, png_byte cb)
{
    int i, j, f;

    i = 0;
    j = R;
    f = 5 - 4 * R;

    circle_pixels(is, js, 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;

        circle_pixels(is, js, i, j, cr, cg, cb);
    }
}

int inside(int i, int j)
{
    return i >= 0 && i < width && j >= 0 && j < height;
}

int pixel_is_color(int i, int j, png_byte r, png_byte g, png_byte b)
{
    png_byte* ptr = &(row_pointers[j][i * 3]);
    return ptr[0] == r && ptr[1] == g && ptr[2] == b;
}

void flood_fill4(int i, int j, png_byte nr, png_byte ng, png_byte nb)
{
    typedef struct {
        int i;
        int j;
    } Point;

    png_byte* ptr;
    png_byte sr, sg, sb;
    Point* stack;
    int max_points;
    int top;

    if(!inside(i, j))
        return;

    ptr = &(row_pointers[j][i * 3]);
    sr = ptr[0];
    sg = ptr[1];
    sb = ptr[2];

    if(sr == nr && sg == ng && sb == nb)
        return;

    max_points = width * height;
    stack = (Point*) malloc(sizeof(Point) * max_points);
    if(!stack)
        abort_("out of memoryy");

    top = 0;
    stack[top++] = (Point){i, j};

    while(top > 0)
    {
        Point p = stack[--top];

        if(!inside(p.i, p.j))
            continue;

        if(!pixel_is_color(p.i, p.j, sr, sg, sb))
            continue;

        write_pixel(p.i, p.j, nr, ng, nb);

        if(top + 4 >= max_points)
        {
            free(stack);
            abort_("[flood_fill4] stack overflow");
        }

        stack[top++] = (Point){p.i - 1, p.j};
        stack[top++] = (Point){p.i, p.j - 1};
        stack[top++] = (Point){p.i + 1, p.j};
        stack[top++] = (Point){p.i, p.j + 1};
    }

    free(stack);
}

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(10, 10, 300, 100, 255, 0, 0);
    //bresenham(10, 100, 300, 10, 0, 0, 0);

    bresenham(90, 120, 145, 120, 0, 0, 0);
    bresenham(145, 120, 145, 265, 0, 0, 0);
    bresenham(145, 265, 250, 120, 0, 0, 0);
    bresenham(250, 120, 310, 120, 0, 0, 0);
    bresenham(310, 120, 190, 290, 0, 0, 0);
    bresenham(190, 290, 315, 480, 0, 0, 0);
    bresenham(315, 480, 255, 480, 0, 0, 0);
    bresenham(255, 480, 145, 320, 0, 0, 0);
    bresenham(145, 320, 145, 480, 0, 0, 0);
    bresenham(145, 480, 90, 480, 0, 0, 0);
    bresenham(90, 480, 90, 120, 0, 0, 0);

    bresenham(350, 120, 465, 140, 0, 0, 0);
    bresenham(465, 140, 530, 260, 0, 0, 0);
    bresenham(530, 260, 525, 335, 0, 0, 0);
    bresenham(525, 335, 485, 390, 0, 0, 0);
    bresenham(485, 390, 405, 390, 0, 0, 0);
    bresenham(405, 390, 405, 480, 0, 0, 0);
    bresenham(405, 480, 355, 480, 0, 0, 0);
    bresenham(355, 480, 350, 120, 0, 0, 0);

    bresenham(405, 190, 460, 200, 0, 0, 0);
    bresenham(460, 200, 485, 255, 0, 0, 0);
    bresenham(485, 255, 485, 320, 0, 0, 0);
    bresenham(485, 320, 455, 350, 0, 0, 0);
    bresenham(455, 350, 405, 345, 0, 0, 0);
    bresenham(405, 345, 405, 190, 0, 0, 0);

    circle(300, 300, 290, 0, 0, 0);

    flood_fill4(300, 300, 255, 255, 150);   // t�o wewn�trz okr�gu
    flood_fill4(110, 200, 255, 120, 0);     // lewa litera
    flood_fill4(370, 250, 0, 200, 120);     // prawa litera - cz�� zewn�trzna
    flood_fill4(440, 250, 255, 180, 220);   // wewn�trzny obszar prawej litery
}


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

        return 0;
}