神奇的伸縮線

程式碼

void setup(){

  size(300,300);

}

float x=200,y=150;

void draw(){

  background(#002966);

  stroke(#b7efff);

  line(100,150,x,y);

  fill(#b7efff);

  noStroke();

  ellipse(100,150,13,13);

  ellipse(x,y,13,13);

  if(!mousePressed){

    float dx=x-100,dy=y-150;

    float len=sqrt(dx*dx+dy*dy);

    x -= dx*(len-100)/len*0.1;

    y -= dy*(len-100)/len*0.1;

  }

}

void mouseDragged(){

  x = mouseX;  y = mouseY;

}