a place to collect useful PDF transformations

Text/PDF/Transformations.hs

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+--------------------------------------------------------------------
+-- |
+-- Module      : Text.PDF.Transformations
+-- Description : Functions for transforming PDF content.
+-- Copyright   : (c) Dylan McNamee 2011
+-- License     : BSD3
+--
+-- Maintainer: Dylan McNamee <dylan@galois.com>
+-- Stability : provisional
+-- Portability: portable
+--
+--------------------------------------------------------------------
+module Text.PDF.Transformations where
+
+import Text.PDF.Types
+
+-- Overlay a string each page of a document
+watermarkDocument :: PDFDocumentParsed -> String -> PDFDocumentParsed
+watermarkDocument doc@(PDFDocumentParsed pages {- _dict -} ) markString = doc {
+        pageList = Prelude.map (appendStreamToPage markString) pages
+        -- , globals = dict
+    }
+
+appendStreamToPage :: String -> PDFPageParsed -> PDFPageParsed
+appendStreamToPage string page = page {
+        contents = case (contents page) of
+            (PDFStream s) -> PDFArray [(PDFStream s), (PDFStream string)]
+            (PDFArray streams) -> PDFArray (streams ++ [(PDFStream string)] )
+            _ -> error "appendStreamToPage: neither Stream nor Array in contents of a page"
+    }