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{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings, ScopedTypeVariables, CPP #-}
{-# LANGUAGE ViewPatterns #-}
{- |
Module : Text.Pandoc.Image
Copyright : Copyright (C) 2020 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Functions for converting images.
-}
module Text.Pandoc.Image ( svgToPng ) where
import Prelude
import Text.Pandoc.Options (WriterOptions(..))
import Text.Pandoc.Process (pipeProcess)
import qualified Data.ByteString.Lazy as L
import System.Exit
import Data.Text (Text)
import Text.Pandoc.Shared (tshow)
import qualified Control.Exception as E
-- | Convert svg image to png. rsvg-convert
-- is used and must be available on the path.
svgToPng :: WriterOptions
-> L.ByteString -- ^ Input image as bytestring
-> IO (Either Text L.ByteString)
svgToPng opts bs = do
let dpi = show $ writerDpi opts
E.catch
(do (exit, out) <- pipeProcess Nothing "rsvg-convert"
["-f","png","-a","--dpi-x",dpi,"--dpi-y",dpi]
bs
return $ if exit == ExitSuccess
then Right out
else Left "conversion from SVG failed")
(\(e :: E.SomeException) -> return $ Left $
"check that rsvg-convert is in path.\n" <> tshow e)
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