Fundamental Graphics Functions

🎯 Introduction

Graphics programming in C allows you to create visual elements and interactive designs using the fundamental graphics functions provided by the graphics.h library. In this tutorial, we will explore the basic concepts of graphics programming in C and learn how to create simple shapes like circles, lines, and rectangles. We will also provide detailed explanations and enhance the existing example program to ensure a better understanding of the concepts.

🎯 Setting up the Graphics Environment

To begin with, you need to set up the graphics environment in C. This involves initializing the graphics driver and the graphics mode using the initgraph() function. Here's the modified code:

Source Code

#include <stdio.h>

#include <graphics.h>


int main() {

   int gd = DETECT, gm, ch;


   initgraph(&gd, &gm, "");


   // Rest of the code goes here


   closegraph();

   return 0;

}

Explanation:

The initgraph() function initializes the graphics driver and graphics mode. It takes three parameters: &gd (the graphics driver), &gm (the graphics mode), and an optional string specifying the path to the BGI driver file.

After the graphics operations are complete, the closegraph() function is called to release the resources used by the graphics system.

🎯 Menu and User Interaction

To provide a menu and enable user interaction, we can enhance the existing code by replacing the clrscr() and printf() functions with graphical equivalents. We can use the outtextxy() function to display text on the graphics window. Here's the modified code:

Source Code

#include <stdio.h>

#include <graphics.h>


int main() {

   int gd = DETECT, gm, ch;


   initgraph(&gd, &gm, "");


   do {

      cleardevice();

      outtextxy(10, 10, "FUNDAMENTALS");

      outtextxy(10, 30, "1. Circle");

      outtextxy(10, 45, "2. Line");

      outtextxy(10, 60, "3. Rectangle");

      outtextxy(10, 75, "4. Exit");


      outtextxy(10, 100, "Enter your choice: ");

      scanf("%d", &ch);

      cleardevice();


      switch (ch) {

         case 1:

            // Code for drawing a circle

            break;

         case 2:

            // Code for drawing a line

            break;

         case 3:

            // Code for drawing a rectangle

            break;

      }


      getch();

   } while (ch <= 3);


   closegraph();

   return 0;

}

Explanation:


🎯 Drawing Shapes

Now let's implement the code for drawing shapes based on the user's choice. We will use the following functions to draw shapes:

Circle:

To draw a circle, we can use the circle() function. Here's the code for drawing a circle:

circle(x, y, radius);

Line: 

To draw a line, we can use the line() function. Here's the code for drawing a line:

line(x1, y1, x2, y2);

Rectangle:

To draw a rectangle, we can use the rectangle() function. Here's the code for drawing a rectangle:

rectangle(left, top, right, bottom);

You can add these shape-drawing codes to the respective cases in the switch statement of the program.

In this tutorial, we learned the fundamentals of graphics programming in C. We explored the basic functions required to set up the graphics environment, display a menu, and draw shapes such as circles, lines, and rectangles. By enhancing the example program, we improved its readability and provided detailed explanations of the concepts. Remember to include the necessary header files and link the graphics library during compilation to successfully run graphics programs in C.