import java.awt.*;
import java.applet.*;
import java.awt.image.ImageProducer;
import java.awt.image.MemoryImageSource;
import java.util.Stack;
public class scanseed extends Applet {
private static final long serialVersionUID = 1L;
int red=Color.red.getRGB();
int blue=Color.red.getRGB();
int black=Color.red.getRGB();
int y,ymax,ymin,w=200,h=200;
Image image;
int pixels[]=new int[w*h];
double x;
double dy,dx;
Point []p=new Point[10];
public void init()
{
p[0] = new Point(15, 15);
p[5] = new Point(145, 35);
p[4] = new Point(145, 95);
p[3] = new Point(115, 115);
p[2] = new Point(65, 115);
p[1] = new Point(15, 75);
p[6] = new Point(85, 65);
p[7]=p[0];
Point q=new Point(4,6);
boundary();
scan(pixels,q,black,blue,red);
ImageProducer ip=new MemoryImageSource(w,h,pixels,0,w);
image=createImage(ip);
}
public void boundary()
{
for(int i=0;i<7;i++)
{
dy=p[i+1].y-p[i].y;
if(dy!=0){
dx=(p[i+1].x-p[i].x)/dy;}
if(dy>0) x=p[i].x;
else x=p[i+1].x;
ymax=(Math.max(p[i].y,p[i+1].y));
ymin=(Math.min(p[i].y,p[i+1].y));
for(y=ymin+1;y<=ymax;y++)
{
x=x+dx;
if(pixels[y*w+(int)(x+0.5)]==red)
pixels[y*w+(int)(x+0.5)+1]=red;//保证是偶数
else
pixels[y*w+(int)(x+0.5)]=red;
}
}
}
public void scan(int[]pixels,Point point,int old_color,int new_color,int boundary_color) {
int x,y,savex,xright,xleft;
Point p;
Stack stack=new Stack();
stack.push(point);
boolean span_need_fill;
while(!stack.empty()) {
p=(Point)(stack.pop());
x=p.x;
y=p.y;
savex=x;
while(pixels[y*w+x]!=boundary_color) {
pixels[y*w+x]=new_color;
x++;
}
xright=x-1;
x=savex-1;
while(pixels[y*w+x]!=boundary_color) {
pixels[y*w+x]=new_color;
x--;
}
xleft=x+1;
x=xleft;
y=y+1;
while(x<=xright) {
span_need_fill=false;
while(pixels[w*y+x]==old_color&&x<=xright) {
span_need_fill=true;
x++;
}
if(span_need_fill) {
p=new Point(x-1,y);
stack.push(p);
span_need_fill=false;
}
while(pixels[y*w+x]!=old_color&&x<=xright)x++;
}
x=xleft;
y=y-2;
while(x<=xright) {
span_need_fill=false;
while(pixels[w*y+x]==old_color) {
span_need_fill=true;
x++;
}
if(span_need_fill) {
p=new Point(x-1,y);
stack.push(p);
span_need_fill=false;
}
while(pixels[y*w+x]!=old_color&&x<=xright)x++;
}
}
}
public void paint(Graphics g)
{
g.drawImage(image, 0, 0, null);
}
}