include stdlib include math include string include SDL include SDL_dra

#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "SDL.h"
#include "SDL_draw.h"
#include "SDL_ttf.h"

/* Константные  значения  */
const  int  width = 1060, height = 660, depth = 16, ybeg = 0, yend = 1;
const double beg_f = -2*3.1415, end_f = -3.1415;

/* График функции */
void draw_func(SDL_Surface *screen, int diff){
    int x0 = 30 ,y0, yt = height-60;
    double x = beg_f, res;

    for(int i=0; i<(width-60); i++){
        res = sqrt(sin(x)/2);
        y0 = fabs(yend - res)*(height-60);
        printf("%d \n", y0);
        x += 0.0031415;
        Draw_Line(screen,x0+i-1, yt+30, x0+i, y0+30,SDL_MapRGB(screen->format, 20,20,20));
        yt = y0;
    }

}

/* Функция Отрисовки  графика  */
void draw(SDL_Surface *screen, TTF_Font *fnt){
    int  n, diffx, diffy, x0 = 30, y0 = 30, x ;
    SDL_Surface *text_surface = NULL;
    char s[5];
    SDL_Color text_color{20, 20, 20};
    SDL_Rect dest{30,5, 1,1};

    /* Рисуем  вериткальные линии */
    for(int i=0; i<=10; i++){
        Draw_VLine(screen,x0,y0, height-y0, SDL_MapRGB(screen->format, 200,200,200));
        x0 += 100;
    }

    /* Рисуем  горизонтальные цифры */
    text_surface = TTF_RenderText_Solid(fnt,"-2Pi", text_color);
    SDL_BlitSurface(text_surface, NULL, screen,&dest);
    dest.x += 1000;
    text_surface = TTF_RenderText_Solid(fnt,"-Pi", text_color);
    SDL_BlitSurface(text_surface, NULL, screen,&dest);

    /* Рисуем горизонтальные  линии */
    n = yend - ybeg;
    diffy = (height - 60)/n;
    x0 = 30;

    for(int i=0; i<=10; i++){
        Draw_HLine(screen,x0,y0, width-x0, SDL_MapRGB(screen->format, 200,200,200));
        y0 += 60;
    }

    /* Рисуем вертикальные  цифры */
    x = ybeg;
    dest.x = 15;
    dest.y = height-40;
    for(int i=0; i<=n; i++){
        itoa(x,s,10); // Преобразование  числа в  строку
        text_surface = TTF_RenderText_Solid(fnt,s, text_color);
        SDL_BlitSurface(text_surface, NULL, screen,&dest);
        dest.y -= diffy;
        x++;
    }

    /* Рисуем  график функции */
    draw_func(screen, diffy);
}
int main ( int argc, char** argv )
{
    int  done = 0;
    SDL_Event event;
    SDL_Rect rect = {0,0,width, height};
    TTF_Font *fnt = NULL;

    /* Инициализируем  видеорежим SDL */
    if ( SDL_Init( SDL_INIT_VIDEO ) < 0 ){
        printf( "Unable to init SDL: %s\n", SDL_GetError() );
        return 1;
    }

    if (TTF_Init()){
        printf( "Unable to init SDL_Font: %s\n", SDL_GetError() );
        return 1;
    }

    /* Создаем  новое  окно */
    SDL_Surface* screen = SDL_SetVideoMode(width, height, depth,SDL_HWSURFACE|SDL_DOUBLEBUF);
    if (!screen ){
        printf("Unable to set SDL video: %s\n", SDL_GetError());
        TTF_Quit();
        SDL_Quit();
        return 1;
    }

    /* Подключение шрифта */
    if(!(fnt = TTF_OpenFont("CharisSILR.ttf", 15))){
        printf("Unable to set Font: %s\n", SDL_GetError());
        TTF_Quit();
        SDL_Quit();
        return 3;
    }

    while (!done){
        while (SDL_PollEvent(&event)){
            // check for messages
            switch (event.type){
                case SDL_QUIT:
                    done = 1;
                    break;
                case SDL_KEYDOWN:{
                    if (event.key.keysym.sym == SDLK_ESCAPE)
                        done = 1;
                    break;
                }
            }
        }

        /* Рисуем график */
        SDL_FillRect(screen, &rect, SDL_MapRGB(screen->format, 255,255,255));
        draw(screen, fnt);

        /* Обновляем экран*/
        SDL_Flip(screen);
    }

    SDL_FreeSurface(screen);
    TTF_CloseFont(fnt);
    TTF_Quit();
    SDL_Quit();
    return 0;
}