/*
  In this example, the canvas is painted with multiple lines going from
 the center of the canvas to the (moving) mouse position.
 
 Painting only occurs during a mouse drag. (i.e. with button down)
 
 A mouse click has the effect of reset the fixed point for the line.
 */

// GLOBAL variables
float x, y;   // fixed point for the line

// This function is executed only once, at the very beginning
void setup() {
  size(500, 400);
  background(255);
  x = 0.5*width;
  y = 0.5*height;
}


// We must include draw function, even though its body is empty
void draw() {
}

// A mouse "click" only occurs when mousePress/mouseRelease coincide
// (that is, without any dragging)
void mouseClicked() {
  x = mouseX;
  y = mouseY;
}

void mouseDragged() {
  line(x, y, mouseX, mouseY);
}

void keyTyped() {
  background(255);
}