Processing Forum Guidelines and Advice

edited March 2018 in Common Questions

Welcome to this forum!

I recommend to read this message fully before posting here, to maximize your experience and the probability to be answered quickly and accurately.

First, some base rules that are usable in any forum. I will list them here briefly, then I will expand on them later.

  • If you have a question, first, search if it hasn't be answered in the past.
  • Choose carefully the category where to put your message.
  • Write a subject informative about the content of your message.
  • Take time to familiarize yourself with the formatting system of this forum.
  • Try to make a message short but precise and to the point.
  • Don't make duplicate messages; but if you change subject, make a new message.

Now, let's be more specific.


You can guess you are not the first to ask a question about SVG, dithering or shape collision!

So it is worth spending a little time to search for your topic. You will save your time and the time of the people providing help!

By doing such search, you might find your answer before even asking the question!

Don't search from the forum. Instead, go to the main site and use the Google powered search (top-right text field) to search the whole site, including the tutorials, the examples, the wiki and the (past) forums.

This is the same as going to Google's search page and typing some topic to search Notice the site: tag limiting searches to the Processing site. "Processing" being a very common name in the computer world, limiting searches can help to narrow the scope of the search.

The wiki, in particular, has a FAQ, a Common Errors and a Troubleshooting page addressing lot of very common questions. This forum category (Common Questions) also has articles addressing questions very frequently asked.

The tutorials cover most of the base topics. And the example sketches shipped with Processing often answer lot of common questions. Don't hesitate to explore them and to run them.


The forum is structured in several categories, some having sub-categories. Among other advantages, it allows people knowledgeable in a field to see if there are messages to be answered in their category.
So by choosing the right category, you increase your chance of being answered quickly and accurately.

For hints about choosing the right category, look at the How to choose a Category in this forum topic.


Take care to write a short but descriptive subject. It is important as people can glance over them and spot a topic they know how to answer.

If you use a library or hardware, mention its name. The author of the library can watch for these topics and answer them in person.

If your problem is specific (sort, collision, mask, etc.), mention it.

It is worth repeating these keywords in the tag section too.

Remember that you can edit your message and amend the subject (or the body; and the category too).

What not to do

Frequently seen errors:

  • ALL CAPS SUBJECTS! Looks like you are yelling for attention, which isn't appreciated...
  • Subjects like "I need help". If you post in a question category, it is rather obvious that you ask for help. It is redundant and uninformative... And imagine a forum where half of the subjects were like this... It would a nightmare to find back a topic!
  • Mentions that you are a newbie / beginner. It is the case for most of the people in the forum anyway, and it is irrelevant for the topic. You can mention this in the body of the message if you feel it is important.
  • Starting the body of the message in the subject. Again, the subject is a digest. Don't hesitate to repeat the information given in the subject in the body of the message.


This forum uses the Markdown formatting system, which is simpler to use than HTML, but can have annoying side effects when you are not careful...

For details how to format your messages, look at the How to format code and text topic.

Body of the message

Try to be short and precise, if possible. It can be useful, if you don't use the latest version of Processing, to specify which version you use. And sometime, the OS you use can be relevant: WinXP, Win7, Win8, Mac OS 10.x,y, Linux Xxx, etc.

Important: try to capture the essence of your question.

In most technical questions, it is useful to show some code to understand the context. Particularly if the question is of the kind "why do I have a NullPointerException?" or "why Processing complains about a missing brace?".

If you have an error, indicate what kind, report the message given by Processing, and indicate which line it highlights. If you have a stack trace (lot of lines in the console area), paste it in the message (format it like code). Avoid showing screenshots of textual information (code or errors): they cannot be searched nor copied and they are often too small (unreadable) and slow to load.

Side sketch

Your question might not be directly related to the hardware or library used in your sketch.

For example, you can receive a bunch of strings from the serial port or out of a library and ask how to sort the strings or eliminate the duplicates. In this case, it is better to make a separate, simple sketch simulating this input (store the strings in an array or a list or read them from a file). This way, you get rid of the dependency on the hardware or library, thus your question is easier to answer for those not having them. It allows to concentrate on your specific problem, and to run your code without having your device or library. Thus, you increase the chance to be answered quickly and accurately.

Note that this technique can be used if you have a big sketch were only part is relevant to your question.


Don't make duplicate threads. Ie. don't ask the same question (or similar to a previous one) in several topics.

It is annoying and one can make efforts to answer in one topic while the other topic can be already answered or with additional information.

But if you change subject, even for the same sketch (eg. going from "how to check for collisions" to "how to display score"), you should make a new topic. Don't hesitate to cross-link to the previous topic.


Another annoyance: students ask for help for their homework, and in fear of being caught, delete their message.

This is totally lacking of respect for those having took time to answer you. And the answers can be useful to somebody searching the forum.

So the moderators always restore the deleted message. Just don't do it, it is useless and annoying. If you don't want your message to be seen, just don't ask it in a public forum!

The worst way to ask for help for homework is to just paste in the text of the assignment and to ask for ready-to-use code...
We are willing to help, and most teachers are OK with asking for help in a forum, but we all expect some work from you. Ie. you should show some code proving you worked on the topic, and you should ask specific questions about what is blocking you.


That's lot of information to digest! Sorry for that, but I tried to address the most frequently found issues with the forum. This way, moderators will have a single topic to point at when addressing these issues.

I hope you will enjoy your forum experience!

Sign In or Register to comment.