Code for saving the sketch as an image for printing

Anyone else creating art for print? :smiley:

I’m currently working on a project where I create images for printing, by drawing to an off-screen buffer (a PGraphics variable), and calling save() on the PGraphics. This allows me to create images larger than my screen resolution, which are likely necessary if you want a high-quality print .

After a few sketches and tweaks I put the code into a “reusable” PDE - in practice I copy and paste the same code to a separate tab when I start a new sketch. Due to my use of PGraphics object for the “final” image which I will print, I made the script to work in two ways:

  1. “S” key will save the contents of the screen to JPG - good for checking out the output, or saving intermediates
  2. “B” key will save the contents of the buffer to TIFF - it looks for a “buffer” variable (all of my sketches in the project). If “buffer” is not found, it tries to find a PGraphics variable regardless of name (a bit overkill, but prevents “breaking” a sketch if there is no “buffer” variable).

Copying and pasting is not best-practice in code reuse or software development, but Processing is not software development anyway :smiley:

Link to gist:


 * Function for saving the generated image into a file when you press "S" or "B" key. 
 * Files will be saved to /out folder, with name: [Sketch name]_[Timestamp].jpg
 * It works in two ways:
 *    1. S key (BASIC) 
 *       If you press the S key ("Save"), it will save the contents of the screen. 
 *       The image is saved in the same resolution as your sketch size. In other words, 
 *       the image will have the same size as  "height" by "width" pixels.
 *    2. B key (ADVANCED)
         If you press the B key (for "Buffer"), it will save the contents of an offscreen 
 *       buffer (a PGraphics object). The image will have the size of the buffer, which
 *       you defined during `buffer = createGraphics(bufferWidth,bufferHeight).` 
 *       For B command, the code looks for a PGraphics variable called "buffer" (which
 *       is the "standard" I use); if it cannot find "buffer", it looks for the first variable
 *       of type PGraphics, regardless of name.  This overengineered way is meant not to break
 *       the sketch if there is no "buffer" variable - likely there are simpler ways to achieve 
 *       the same.
 * Version: 27.07.2018

import java.text.SimpleDateFormat;  
import java.util.Date;  
import java.util.*;
import java.lang.reflect.Field;

PGraphics bufferToSave;

void keyPressed() {
  String sketchName = this.getClass().getName();
  SimpleDateFormat formatter = new SimpleDateFormat("YYYYMMDD_HHmmss");  
  Date date = new Date();

  String fileName = String.format("/out/%s_%s.jpg", sketchName, formatter.format(date));
  if (key == 'S' || key == 's') {
    saveTo(null, fileName);
  } else if (key== 'B' || key == 'b') {
    bufferToSave = getBuffer();
    saveTo(bufferToSave, fileName);

void saveTo(PGraphics source, String fileName) {
  if (source != null) {;
    println(String.format("Contents of buffer saved to %s", fileName));
  } else {
    println(String.format("Contents of screen saved to %s", fileName));

 * Returns the first instance of PGraphics found in the sketch, in no particular order.
PGraphics getBuffer() {
  //looking for a variable called "buffer"
  try {
    Field bufferField = this.getClass().getField("buffers");
    if (bufferField != null)
      return (PGraphics)bufferField.get(this);
  catch(NoSuchFieldException ex) {

  catch ( IllegalAccessException ex ) {

  //if "buffer" not found, then look for first instance of PGraphics
  Field[] fields = this.getClass().getDeclaredFields();

  //print field names paired with their values
  for ( Field field : fields  ) {      
    try {
      if (field.getType().getName().contains("PGraphics")) {        
        return (PGraphics)field.get(this);
    catch ( IllegalAccessException ex ) {
  return null;

you could treat as pdf, see this:

or you could do the following:

PGraphics big;  // Declare a PGraphics variable

void setup() {
  big = createGraphics(3000, 3000);  // Create a new PGraphics object
  big.beginDraw();                   // Start drawing to the PGraphics object 
  big.background(128);               // Set the background
  big.line(20, 1800, 1800, 900);     // Draw a line
  big.endDraw();                     // Stop drawing to the PGraphics object"big.tif");

*withdrawn from:

Thanks @erwrow! That’s pretty much what my code does, but “save” is called only you press “S” key in the keyboard.