Chapter 3: Example 3-4: Drawing a Continuous Line

// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com

// Example 3-4: Drawing a continuous line
void setup() {
  size(200, 200);
  background(255);
  smooth();
}

void draw() {
  stroke(0);
  // Draw a line from previous mouse location to current mouse location.
  line(pmouseX, pmouseY, mouseX, mouseY);
}

2 Comments

---

»

1. What would be the easiest way to get the line to start from a default point that was different from (0,0)?

   Comment by Rupert — January 3, 2010 @ 4:39 pm

2. Processing always initializes the mouse location at 0,0 for the first frame. You could check and make sure the values are not 0,0 before you draw:

     if (!(pmouseX == 0 && pmouseY == 0)) {
       line(pmouseX, pmouseY, mouseX, mouseY);
     }
   

   And even use your own variable to set up another starting point for when the values are 0,0.

   Comment by Daniel Shiffman — January 4, 2010 @ 12:19 pm

Leave a comment