How do you write a graphics program of Indian flag using class?

Answer 1

// INDIAN FLAG : SIMPLE PROGRAM //

#include<graphics.h>

#include<stdio.h>

#include<conio.h>

#include<math.h>

void main()

{

int gdriver=DETECT, gmode, xc=195, yc=175;

double deg, max, x, y, newx, newy, i, move;

initgraph (&gdriver, &gmode, "--path--");

rectangle (100, 100, 300, 250);

rectangle (90, 100, 100, 400);

line (100, 150, 300, 150);

line (100, 200, 300, 200);

setfillstyle (SOLID_FILL, LIGHTRED);

floodfill (110, 110, WHITE);

setfillstyle (SOLID_FILL, WHITE);

floodfill (110, 160, WHITE);

setfillstyle (SOLID_FILL, GREEN);

floodfill (110, 210, WHITE);

setfillstyle (SOLID_FILL, BROWN);

floodfill (91, 101, WHITE);

setcolor (BLUE);

circle (xc, yc, 20);

deg= (double)(15 * 3.14 / 180);

max= (double)(360 * 3.14 / 180);

move= deg;

x= xc;

y= 155;

line (xc, yc, x, y);

for (i= deg; i<= max; i+= move)

{

newx= xc + (x-xc)*cos(i) + (y-yc)*sin(i);

newy= yc - (x-xc)*sin(i) + (y-yc)*cos(i);

line (xc, yc, newx, newy);

}

putpixel (xc, yc, 15);

delay (500);

getch ();

closegraph ();

}

Answer 2

If you want to use classes you need to use an object-oriented language, such as C++ or Java.

To create a flag class you will need a base class (flag) plus some derived classes to cater for common layouts such as tricolours and Saltires. The Indian national flag is derived from a horizontal tricolour with orange, white and green bands of equal width. In the centre of the white band there is an Ashoka Chakra, a 24 spoked Wheel of Life.

The Ashoka Chakra is the hardest part to implement, however the geometry is reasonably simple and can be achieved by overlaying a white circle on top of a slightly larger blue circle to create the outer blue ring, with blue quadrilaterals for the spokes. There are 24 spokes in total so these need to be arranged at 15 degree intervals from top centre. There are also 24 semi-circles around the inner edge of the blue ring, but these can be drawn using small blue circles centred on the large white circle's circumference. The diameter of these circles is equal to the circumference of the inner edge divided by 48. The semi-circles also sit between the spokes, so the first semi-circle will be centred 7.5 degrees from top centre, with 15 degree intervals thereafter.

The spokes are formed from diamond-shaped quadrilaterals. If we imagine a circle that is half the diameter of the inner white circle, then its circumference will intersect the mid-points which should be about 3 degrees either side of the outer and inner points. The outer point should hit an imaginary circle with a diameter that is equal to the white inner circle minus one of the small blue circles while the inner point should start on a circle that is roughly twice the diameter of a small blue circle. The first spoke has inner and outer points 0 degrees from top centre while the points of each subsequent spoke are offset 15 degrees from the points of the previous one.

Your graphics library should provide all the facilities you need, which is essentially filled polygons and circles. However, to avoid any flickering during a resize, you should use double-buffering to calculate the geometry and draw the flag in memory before bit-blasting the complete image to the view port for display.