Main.hs

module Main where

-- https://github.com/Yuras/pdf-toolbox/issues/62

import Pdf.Document
import qualified Pdf.Core as PC
import System.Environment
import qualified Data.Text as T

printRect :: String -> IO ()
printRect f = withPdfFile f $ \pdf ->
    do
        doc <- document pdf
        catalog <- documentCatalog doc
        pagenode <- catalogPageNode catalog
        txt <- extract pdf pagenode
        print txt

extract :: Pdf -> PageNode -> IO T.Text
extract pdf = e . f
  where
{- hlint ignore "Use <=<" -}
    e :: IO [T.Text] -> IO T.Text
    e = (T.concat <$>)

    a :: IO [PC.Ref] -> IO [T.Text]
    a = do
        let b :: IO PageTree -> IO T.Text
            b = (>>= go)
        let c :: PC.Ref -> IO PageTree
            c = loadPageNode pdf
        let d :: PC.Ref -> IO T.Text
            d = b . c
        (>>= traverse d)

    go :: PageTree -> IO T.Text
    go (PageTreeLeaf l) = pageMediaBox l >>= \r -> return $ T.pack . show $ r
    go (PageTreeNode n) = extract pdf n

    f :: PageNode -> IO [T.Text]
    f = a . pageNodeKids

-- Main function
main :: IO ()
main = do
    args <- getArgs
    case args of
        [filePath] -> printRect filePath
        _ -> putStrLn "Usage: program name <pdf-file>"