diff options
Diffstat (limited to 'src/Text/Pandoc/ImageSize.hs')
| -rw-r--r-- | src/Text/Pandoc/ImageSize.hs | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs index 9b0850efb..e2a8b8283 100644 --- a/src/Text/Pandoc/ImageSize.hs +++ b/src/Text/Pandoc/ImageSize.hs @@ -53,7 +53,8 @@ imageType :: ByteString -> Maybe ImageType imageType img = case B.take 4 img of "\x89\x50\x4e\x47" -> return Png "\x47\x49\x46\x38" -> return Gif - "\xff\xd8\xff\xe0" -> return Jpeg + "\xff\xd8\xff\xe0" -> return Jpeg -- JFIF + "\xff\xd8\xff\xe1" -> return Jpeg -- Exif "%PDF" -> return Pdf "%!PS" | (B.take 4 $ B.drop 1 $ B.dropWhile (/=' ') img) == "EPSF" @@ -139,8 +140,14 @@ gifSize img = do jpegSize :: ByteString -> Maybe ImageSize jpegSize img = do let (hdr, rest) = B.splitAt 4 img - guard $ hdr == "\xff\xd8\xff\xe0" guard $ B.length rest >= 14 + case hdr of + "\xff\xd8\xff\xe0" -> jfifSize rest + "\xff\xd8\xff\xe1" -> exifSize rest + _ -> mzero + +jfifSize :: ByteString -> Maybe ImageSize +jfifSize rest = do let [dpiDensity,dpix1,dpix2,dpiy1,dpiy2] = map fromIntegral $ unpack $ B.take 5 $ B.drop 9 $ rest let factor = case dpiDensity of @@ -149,11 +156,11 @@ jpegSize img = do _ -> const 72 let dpix = factor (shift dpix1 8 + dpix2) let dpiy = factor (shift dpiy1 8 + dpiy2) - (w,h) <- findJpegSize rest + (w,h) <- findJfifSize rest return $ ImageSize { pxX = w, pxY = h, dpiX = dpix, dpiY = dpiy } -findJpegSize :: ByteString -> Maybe (Integer,Integer) -findJpegSize bs = do +findJfifSize :: ByteString -> Maybe (Integer,Integer) +findJfifSize bs = do let bs' = B.dropWhile (=='\xff') $ B.dropWhile (/='\xff') bs case B.uncons bs' of Just (c,bs'') | c >= '\xc0' && c <= '\xc3' -> do @@ -165,8 +172,23 @@ findJpegSize bs = do [c1,c2] -> do let len = shift c1 8 + c2 -- skip variables - findJpegSize $ B.drop len bs'' + findJfifSize $ B.drop len bs'' _ -> fail "JPEG parse error" Nothing -> fail "Did not find length record" +exifSize :: ByteString -> Maybe ImageSize +exifSize rest = do + let bs' = B.takeWhile (/='\xff') $ B.drop 8 rest -- exif data + let (_,bs'') = B.breakSubstring "\xa0\x02" bs' -- width + let rawWidth = B.take 2 $ B.drop 10 bs'' + let (_,bs''') = B.breakSubstring "\xa0\x03" bs' -- height + let rawHeight = B.take 2 $ B.drop 10 bs''' + let tonum bs = case map fromIntegral $ unpack bs of + [x,y] -> Just $ shift x 8 + y + _ -> Nothing + case (tonum rawWidth, tonum rawHeight) of + (Just w, Just h) -> + return $ ImageSize { pxX = w, pxY = h, dpiX = 72, dpiY = 72 } + _ -> fail "Could not determine exif image size" + -- some day, figure out how to parse dpi from exif |