This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

SaveFile 2

This file a PrintWriter object to write data continuously to a file while the mouse is pressed. When a key is pressed, the file closes itself and the program is stopped.

PrintWriter output;

void setup() 
  size(200, 200);
  // Create a new file in the sketch directory
  output = createWriter("positions.txt");

void draw() 
  if (mousePressed) {
    point(mouseX, mouseY);
    // Write the coordinate to a file with a
    // "\t" (TAB character) between each entry
    output.println(mouseX + "\t" + mouseY);

void keyPressed() { // Press a key to save the data
  output.flush(); // Write the remaining data
  output.close(); // Finish the file
  exit(); // Stop the program