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import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
public class MidpointCircle extends Applet{
int X,Y, scale = 7;
int convertX(int x) {
return X + x * scale;
}
int convertY(int y) {
return X- y * scale;
}
public void init() {
setSize(900, 900);
setBackground(new Color(255,255,255));
addMouseWheelListener(new MouseWheelListener() {
@Override
public void mouseWheelMoved(MouseWheelEvent event) {
scale += event.getWheelRotation();
repaint();
}
});
}
public void midpointCircle(Graphics g, int xc, int yc, int r){
int x=0;
int y=r;
int p = 1-r;
while(x<=y){
g.fillRect((int) (X+ (xc*scale) + ((int) x) * scale) - scale / 2, (int) (Y+ (yc*scale) - ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) - ((int) x) * scale) - scale / 2, (int) (Y+ (yc*scale) - ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) + ((int) x) * scale) - scale / 2, (int) (Y+ (yc*scale) + ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) - ((int) x) * scale) - scale / 2, (int) (Y+ (yc*scale) + ((int) y) * scale) - scale / 2, scale, scale);
x+=1;
if(p>0){
y-=1;
p+=(2*x-2*y-1);
}
else if(p<=0){
p+=(2*x+1);
}
}
x=r;
y=0;
p=1-r;
while(x>y){
g.fillRect((int) (X+ (xc*scale) + ((int) x) * scale) - scale / 2, (int) (Y + (yc*scale) - ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) - ((int) x) * scale) - scale / 2, (int) (Y + (yc*scale) - ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) + ((int) x) * scale) - scale / 2, (int) (Y + (yc*scale) + ((int) y) * scale) - scale / 2, scale, scale);
g.fillRect((int) (X+ (xc*scale) - ((int) x) * scale) - scale / 2, (int) (Y + (yc*scale) + ((int) y) * scale) - scale / 2, scale, scale);
y+=1;
if(p<=0)
p+=(2*y+1);
else{
x-=1;
p+=(2*y-2*x+1);
}
}
}
public void paint(Graphics g){
X = getWidth() / 2;
Y = getHeight() / 2;
g.setColor(Color.green);
for (int x = scale; x <= getWidth(); x += scale) {
g.drawLine(X + x, 0, X + x, getHeight());
g.drawLine(X - x, 0, X - x, getHeight());
}
for (int y = scale; y <= getWidth(); y += scale) {
g.drawLine(0, Y + y, getWidth(), Y + y);
g.drawLine(0, Y- y, getWidth(), Y- y);
}
g.setColor(Color.red);
g.drawLine(X, 0, X, getHeight());
g.drawLine(0, Y, getWidth(), Y);
g.setColor(Color.blue);
midpointCircle(g, -22, -22, 10);
g.setColor(Color.blue);
midpointCircle(g, 22, -22, 10);
g.setColor(Color.red);
midpointCircle(g, 0, 0, 20);
g.setColor(Color.black);
midpointCircle(g, 0, 0, 3);
g.setColor(Color.black);
midpointCircle(g, -10, -10, 2);
g.setColor(Color.black);
midpointCircle(g, 10, -10, 2);
}
}
/*
<applet code="MidpointCircle" width="900" height="900"> </applet>
*/ |