function setup() {

  createCanvas(300, 300);

}



function draw() {

  background(250, 250, 250);

  line(0, mouseY, 300, mouseY);

  line(mouseX, 0, mouseX, 300);

  ellipse(mouseX, mouseY, 10);



  fill(0, 0, 0);

  text("座標(" + int(mouseX) + "," + int(mouseY) + ")", 20, 30);

}

point(140, 150);