Processing: Creative Coding and Computational Art

The Processing window is divided into horizontal bands of varying height. I’ll deal with
each, from the bottom up.
The line number, at the very bottom of the window, shows you what line of code you are
currently working on, based on your cursor position.
The text area gives you verbose feedback about bugs in your code. It can be scary and
frustrating to new coders to see all these errors come up in the text area when they first
begin coding; rest assured, it happens to all of us. New coders often struggle to even find
the errors in their code, and it can seem impossible that a typo or logic error could still
possibly exist in code you’ve painstakingly gone through numerous times. The errors will
likely also seem annoyingly cryptic, but over time you’ll learn to understand the messages
and more quickly track down your bugs. However, there are times when even experienced
coders struggle to eradicate bugs. I usually find taking a break helps (as well as screaming
obscenities at the top of my lungs). Eventually, you’ll appreciate these verbose error messages
and see how valuable they are in the debugging process. Processing also includes
two commands, print() and println(), that allow you to output information about your
sketch to the text area.
The message area gives you quick feedback during saving and exporting, and tells you in
plain, simple language about errors in your code.
The text editor is where you write your sketch code; it’s essentially your old text editor. If
you play with it, you’ll notice that there are clear feedback color cues, showing you what
line your cursor is on, what text is selected, and if a word you typed is a legal keyword in
the language.
The tabs show you what files you are working with. Tabs are really handy when your sketch
requires multiple files. At the right side of the tabs area is a right-facing arrow button.
Pressing this button opens a pop-up menu that allows you to create and manage your
tabs. When you open an existing sketch in Processing, any Java or PDE files in your sketch
directory will be automatically put into the tabs layout. The benefit of this will become
clearer when you begin to work with external functions and classes. By default, there will
always be at least one tab open, with its name at the bottom of the tab pop-up menu. This
tab will be your current main sketch PDE file (it’s called a PDE file because .pde is just the
suffix that Processing sketches use—it stands for “Processing development environment”).
As more tabs are created, you’ll see the new tab names at the bottom of the tabs pop-up
menu as well. You can select one of these names by clicking on it to give the tab focus
(make it the active window) in the Processing project window. When you click on the tabs
arrow button, the pop-up menu allows you to do the following:
Create a new tab
Rename a tab
Delete a tab
Hide/unhide a tab
Move focus to the previous/next tab
THE PROCESSING ENVIRONMENT
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