This passage will discuss the basics of PDF creation:

• how to create PDF files, and streams using hummus.createWriter. then finishing them.
• adding pages with and writing them

a short example on how to do both is available here

The hummus module has createWriter method is used for starting a PDF file or stream:

createWriter(inFileName,[inOptions]);
createWriter(inStreamObject,[inOptions]);

The method returns a PDFWriter object that you can now use to add pages and content.

The method has possible first parameters. You can either choose to write to a file, in which case you'll pass a string leading to this file path (it is utf8 encoded, like all strings used in the module).
You can alternatively pass a stream object, which is simply an object implementing two methods (write and getCurrentPosition). The Hummus module comes with Hummus.PDFStreamForResponse which is a class implementing such a stream object, that can be used for writing directly to the response stream for a server. For more information about custom streams, visit Custom streams;

The second, optional, object provide options for the PDF file creation. It may have the following members:

• version - a number value stating the version of the desired PDF. default is 13 (PDF 1.3). Any number between 10 and 17 works. You can use hummus. ePDFVersion10 to hummus.ePDFVersion13 if you prefer nice symbols.
• compress - the PDF streams are normally compressed using flate compression. If you want to cancel this (maybe for debugging, or whatnot), set this member value to false.
• log - For debugging purposes, if something goes wrong, use this option to allow the internal library to provide some log notes. log parameter should be set to a file path where the end result log should reside in.Note! when using the log the module/library is no longer thread safe. So unless for debugging, avoid.

To finish a PDF file simply call the created PDFWriter end method. Like this:

pdfWriter.end()

To start writing a PDF page, use the createPage method of the PDFWriter object, passing 4 numbers that serve as the page media box, like this:

pdfWriter.createPage(0,0,595,842)

The method will return a PDFPage object that you can later use to add context to.
The PDFPage object has a property mediaBox that can be used to get or set an array of 4 numbers, used as the page media box. Note that because of that it's perfectly OK to pass nothing to createPage and set the media box later.

When done providing content to a page, write it with pdfWriter.writePage(aPage).