{$N+}
uses graph,crt;
const POLYSIZE=4+1;
STEP=0.01;
const xy:array[1..POLYSIZE]of PointType=(
(x:100;y:100),
(x:100;y:150),
(x:200;y:150),
(x:200;y:100),
(x:100;y:100));
x0=100;
y0=100;
var gd,gm,i:integer;
r:array[1..POLYSIZE]of double;
fi:array[1..POLYSIZE]of double;
alp:double;
begin
gd:=DETECT;
initgraph(gd,gm,'');
for i:=1 to POLYSIZE do
begin
r[i]:=sqrt(sqr(xy[i].x-x0)+sqr(xy[i].y-y0));
if(xy[i].x-x0<>0)then fi[i]:=arctan((xy[i].y-y0)/(xy[i].x-x0))
else if xy[i].y-y0<0 then fi[i]:=-PI/2
else if xy[i].y-y0>0 then fi[i]:=PI/2 else fi[i]:=0;
end;
repeat
for i:=1 to POLYSIZE do
begin
xy[i].x:=x0+round(r[i]*cos(fi[i]+alp));
xy[i].y:=y0+round(r[i]*sin(fi[i]+alp));
end;
setcolor(WHITE);
drawpoly(POLYSIZE,xy);
delay(1000);
setcolor(BLACK);
drawpoly(POLYSIZE,xy);
alp:=alp+STEP;
until keypressed;
closegraph;
end. |
