a_device.c

一个动画演示的例子,画了一个正方形和一个圆,正方形不动而保存和恢复屏幕使圆移动.

#include "graphics.h" 
#include "math.h" 
#include "dos.h" 
#include "conio.h" 
#include "stdlib.h" 
#include "stdio.h" 
#include "stdarg.h" 
#define MAXPTS 15 
#define PI 3.1415926 
struct PTS { 
int x,y; 
}; 
double AspectRatio=0.85; 

void LineToDemo(void) 
{ 
struct viewporttype vp; 
struct PTS points[MAXPTS]; 
int i, j, h, w, xcenter, ycenter; 
int radius, angle, step; 
double rads; 
printf(" MoveTo / LineTo Demonstration" ); 
getviewsettings( &vp ); 
h = vp.bottom - vp.top; 
w = vp.right - vp.left; 
xcenter = w / 2; /* Determine the center of circle */ 
ycenter = h / 2; 
radius = (h - 30) / (AspectRatio * 2); 
step = 360 / MAXPTS; /* Determine # of increments */ 
angle = 0; /* Begin at zero degrees */ 
for( i=0 ; i<MAXPTS ; ++i ){ /* Determine circle intercepts */ 
    rads = (double)angle * PI / 180.0; /* Convert angle to radians */ 
    points[i].x = xcenter + (int)( cos(rads) * radius ); 
    points[i].y = ycenter - (int)( sin(rads) * radius * AspectRatio ); 
    angle += step; /* Move to next increment */ 
    } 
circle( xcenter, ycenter, radius ); /* Draw bounding circle */
for( i=0 ; i<MAXPTS ; ++i ){ /* Draw the cords to the circle */ 
for( j=i ; j<MAXPTS ; ++j ){ /* For each remaining intersect */ 
moveto(points[i].x, points[i].y); /* Move to beginning of cord */ 
lineto(points[j].x, points[j].y); /* Draw the cord */ 
} } } 
main() 
{int driver,mode; 
driver=CGA;mode=CGAC0; 
initgraph(&driver,&mode,""); 
setcolor(3); 
setbkcolor(GREEN); 
LineToDemo();
getch();
}