Imagine that you need to generate a few thousand vector images to print postcards. To streamline your process, you probably want to generate PDF files with the exact dimensions, so that you don't have to crop them manually.
You need to define the size of your final print first. Let's say that you'll use a standard A4 sheet of paper. The dimensions of this piece of paper are 210 x 297 millimeters, or 8.2677 x 11.6929 inches. The final size of your sketch will be 595 x 842 pixels. You can define the size of an A4 sheet of paper inside the setup() function, as done in the following code:
void setup()
{
size( 595, 842 );
}The only thing you need to know is that Processing displays everything on the screen with a resolution of 72 dots per inch (DPI). If you use the metric system, you'll need to convert the size of your final output from millimeters to inches first. One inch is 25.4 millimeters. If you use the imperial system, you won't need...