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| C Program To Display Circles |
#include /* For graphics library functions */
#include /* For exit() */
#include
#include
int set_graph(void); /* Initialize graphics */
void calc_coords(void); /* Scale distances onscreen */
void draw_planets(void); /* Draw and fill planet circles */
/* Draw one planet circle */
void draw_planet(float x_pos, float radius,
int color, int fill_style);
void get_key(void); /* Display text on graphics screen, */
/* wait for key */
/* Global variables -- set by calc_coords() */
int max_x, max_y; /* Maximum x- and y-coordinates */
int y_org; /* Y-coordinate for all drawings */
int au1; /* One astronomical unit in pixels
(inner planets) */
int au2; /* One astronomical unit in pixels
(outer planets) */
int erad; /* One earth radius in pixels */
int main()
{
/* Exit if not EGA or VGA */
/* Find out if they have what it takes */
if (set_graph() != 1) {
printf("This program requires EGA or VGA graphics\n");
exit(0);
}
calc_coords(); /* Scale to graphics resolution in use */
draw_planets(); /* Sun through Uranus (no room for others) */
get_key(); /* Display message and wait for key press */
closegraph(); /* Close graphics system */
return 0;
}
int set_graph(void)
{
int graphdriver = DETECT, graphmode, error_code;
/* Initialize graphics system; must be EGA or VGA */
initgraph(&graphdriver, &graphmode, "..\\bgi");
error_code = graphresult();
if (error_code != grOk)
return(-1); /* No graphics hardware found */
if ((graphdriver != EGA) && (graphdriver != VGA))
{
closegraph();
return 0;
}
return(1); /* Graphics OK, so return "true" */
}
void calc_coords(void)
{
/* Set global variables for drawing */
max_x = getmaxx(); /* Returns maximum x-coordinate */
max_y = getmaxy(); /* Returns maximum y-coordinate */
y_org = max_y / 2; /* Set Y coord for all objects */
erad = max_x / 200; /* One earth radius in pixels */
au1 = erad * 20; /* Scale for inner planets */
au2 = erad * 10; /* scale for outer planets */
}
void draw_planets()
{
/* Each call specifies x-coordinate in au, radius, and color */
/* arc of Sun */
draw_planet(-90, 100, EGA_YELLOW, EMPTY_FILL);
/* Mercury */
draw_planet(0.4 * au1, 0.4 * erad, EGA_BROWN, LTBKSLASH_FILL);
/* Venus */
draw_planet(0.7 * au1, 1.0 * erad, EGA_WHITE, SOLID_FILL);
/* Earth */
draw_planet(1.0 * au1, 1.0 * erad, EGA_LIGHTBLUE, SOLID_FILL);
/* Mars */
draw_planet(1.5 * au1, 0.4 * erad, EGA_LIGHTRED, CLOSE_DOT_FILL);
/* Jupiter */
draw_planet(5.2 * au2, 11.2 * erad, EGA_WHITE, LINE_FILL);
/* Saturn */
draw_planet(9.5 * au2, 9.4 * erad, EGA_LIGHTGREEN, LINE_FILL);
/* Uranus */
draw_planet(19.2 * au2, 4.2 * erad, EGA_GREEN, LINE_FILL);
}
void draw_planet(float x_pos, float radius, int color, int fill_style)
{
setcolor (color); /* This becomes drawing color */
circle(x_pos, y_org, radius); /* Draw the circle */
setfillstyle(fill_style, color); /* Set pattern to fill interior */
floodfill(x_pos, y_org, color); /* Fill the circle */
}
void get_key(void)
{
outtextxy(50, max_y - 20, "Press any key to exit");
getch();
}
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