From HaskellWiki

For the following recipes you need to install HPDF.

1 Creating an empty PDF file

runPdf generates a PDF file in the file system. You need to pass it four things:

• a file name for the PDF file
• document information, an instance of PDFDocumentInfo. You can use the data generated by standardDocInfo.
• the default page size, an instance of PDFRect.
• a PDF Action

Let's create an empty PDF file with the name "test1.pdf":

import Graphics.PDF
 
main :: IO ()
main = do
  let outputFileName= "test1.pdf"
  let documentInfo = standardDocInfo 
  let defaultPageSize = PDFRect 0 0 200 300
 
  runPdf outputFileName documentInfo defaultPageSize $ do
    addPage Nothing

2 Pages with different sizes

If you pass "Nothing" to the function addPage, the default page size will be used for the size of the new page.

Let’s create three pages, the last two pages with different dimensions:

import Graphics.PDF
 
main :: IO ()
main = do
  let outputFileName= "test2.pdf"
  let documentInfo = standardDocInfo 
  let defaultPageSize = PDFRect 0 0 200 300
 
  runPdf outputFileName documentInfo defaultPageSize $ do
    addPage Nothing
    addPage $ Just $ PDFRect 0 0 100 100
    addPage $ Just $ PDFRect 0 0 150 150