diff options
| -rw-r--r-- | src/Text/Pandoc/ImageSize.hs | 50 |
1 files changed, 19 insertions, 31 deletions
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs index fc9e1854b..8517d07c2 100644 --- a/src/Text/Pandoc/ImageSize.hs +++ b/src/Text/Pandoc/ImageSize.hs @@ -54,6 +54,8 @@ import Control.Monad.Except import Control.Applicative import Data.Maybe (fromMaybe) import qualified Data.Attoparsec.ByteString.Char8 as A +import qualified Codec.Picture.Metadata as Metadata +import Codec.Picture (decodeImageWithMetadata) -- quick and dirty functions to get image sizes -- algorithms borrowed from wwwis.pl @@ -122,7 +124,7 @@ findSvgTag img = "<svg" `B.isInfixOf` img || "<SVG" `B.isInfixOf` img imageSize :: WriterOptions -> ByteString -> Either T.Text ImageSize imageSize opts img = checkDpi <$> case imageType img of - Just Png -> mbToEither "could not determine PNG size" $ pngSize img + Just Png -> pngSize img Just Gif -> mbToEither "could not determine GIF size" $ gifSize img Just Jpeg -> jpegSize img Just Svg -> mbToEither "could not determine SVG size" $ svgSize opts img @@ -300,36 +302,22 @@ pPdfSize = do , dpiY = 72 } ) <|> pPdfSize -pngSize :: ByteString -> Maybe ImageSize -pngSize img = do - let (h, rest) = B.splitAt 8 img - guard $ h == "\x8a\x4d\x4e\x47\x0d\x0a\x1a\x0a" || - h == "\x89\x50\x4e\x47\x0d\x0a\x1a\x0a" - let (i, rest') = B.splitAt 4 $ B.drop 4 rest - guard $ i == "MHDR" || i == "IHDR" - let (sizes, rest'') = B.splitAt 8 rest' - (x,y) <- case map fromIntegral $unpack sizes of - ([w1,w2,w3,w4,h1,h2,h3,h4] :: [Integer]) -> return - (shift w1 24 + shift w2 16 + shift w3 8 + w4, - shift h1 24 + shift h2 16 + shift h3 8 + h4) - _ -> Nothing -- "PNG parse error" - (dpix, dpiy) <- findpHYs rest'' - return ImageSize { pxX = x, pxY = y, dpiX = dpix, dpiY = dpiy } - -findpHYs :: ByteString -> Maybe (Integer, Integer) -findpHYs x - | B.null x || "IDAT" `B.isPrefixOf` x = return (72,72) - | "pHYs" `B.isPrefixOf` x = - case map fromIntegral $ unpack $ B.take 9 $ B.drop 4 x of - [x1,x2,x3,x4,y1,y2,y3,y4,u] -> do - let factor = if u == 1 -- dots per meter - then \z -> z * 254 `div` 10000 - else const 72 - return - ( factor $ shift x1 24 + shift x2 16 + shift x3 8 + x4, - factor $ shift y1 24 + shift y2 16 + shift y3 8 + y4 ) - _ -> mzero - | otherwise = findpHYs $ B.drop 1 x -- read another byte +pngSize :: ByteString -> Either T.Text ImageSize +pngSize img = + case decodeImageWithMetadata img of + Left e -> Left (T.pack e) + Right (_, meta) -> do + pxx <- maybe (Left "Could not determine width") Right $ + Metadata.lookup Metadata.Width meta + pxy <- maybe (Left "Could not determine height") Right $ + Metadata.lookup Metadata.Height meta + dpix <- maybe (Right 72) Right $ Metadata.lookup Metadata.DpiX meta + dpiy <- maybe (Right 72) Right $ Metadata.lookup Metadata.DpiY meta + return $ ImageSize + { pxX = fromIntegral pxx + , pxY = fromIntegral pxy + , dpiX = fromIntegral dpix + , dpiY = fromIntegral dpiy } gifSize :: ByteString -> Maybe ImageSize gifSize img = do |