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authorJohn MacFarlane <fiddlosopher@gmail.com>2012-01-15 15:40:26 -0800
committerJohn MacFarlane <fiddlosopher@gmail.com>2012-01-15 15:40:26 -0800
commit691b7bdc66acdd5c9ac1f1b1800593995f117a71 (patch)
tree5500591f10d7b20ac4da2662b02c7836620bcbde
parent28a043fe44bacb3e0e24b9f4e9402480d50d665a (diff)
downloadpandoc-691b7bdc66acdd5c9ac1f1b1800593995f117a71.tar.gz
ImageSize: extract dpi information from PNG and JPEG.
* ImageSize record now includes dpiX, dpiY, pxX, pxY. * New functions sizeInPixels and sizeInPoints.
-rw-r--r--src/Text/Pandoc/ImageSize.hs134
-rw-r--r--src/Text/Pandoc/Writers/ODT.hs9
2 files changed, 93 insertions, 50 deletions
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs
index 4a7a21dd3..23bb2f739 100644
--- a/src/Text/Pandoc/ImageSize.hs
+++ b/src/Text/Pandoc/ImageSize.hs
@@ -1,37 +1,38 @@
{-# LANGUAGE OverloadedStrings, ScopedTypeVariables #-}
{-
-Copyright (C) 2011 John MacFarlane <jgm@berkeley.edu>
+ Copyright (C) 2011 John MacFarlane <jgm@berkeley.edu>
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
--}
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ -}
{- |
- Module : Text.Pandoc.ImageSize
- Copyright : Copyright (C) 2011 John MacFarlane
- License : GNU GPL, version 2 or above
+Module : Text.Pandoc.ImageSize
+ Copyright : Copyright (C) 2011 John MacFarlane
+ License : GNU GPL, version 2 or above
- Maintainer : John MacFarlane <jgm@berkeley.edu>
- Stability : alpha
- Portability : portable
+ Maintainer : John MacFarlane <jgm@berkeley.edu>
+ Stability : alpha
+ Portability : portable
-Functions for determining the size of a PNG, JPEG, or GIF image.
+ Functions for determining the size of a PNG, JPEG, or GIF image.
-Algorithms borrowwed from wwwis.pl (c) 2005 Alex K, released
-under the GPL.
--}
-module Text.Pandoc.ImageSize ( ImageType(..), imageType, imageSize, readImageSize ) where
+ Algorithms borrowwed from wwwis.pl (c) 2005 Alex K, released
+ under the GPL.
+ -}
+ module Text.Pandoc.ImageSize ( ImageType(..), imageType, imageSize,
+ sizeInPixels, sizeInPoints, readImageSize ) where
import Data.ByteString.Lazy (ByteString, unpack)
import qualified Data.ByteString.Lazy.Char8 as B
import Control.Monad
@@ -42,10 +43,15 @@ import Data.Bits
data ImageType = Png | Gif | Jpeg deriving Show
-type Height = Integer
-type Width = Integer
+data ImageSize = ImageSize{
+ pxX :: Integer
+ , pxY :: Integer
+ , dpiX :: Integer
+ , dpiY :: Integer
+ } deriving (Read, Show, Eq)
-readImageSize :: FilePath -> IO (Maybe (Width,Height))
+
+readImageSize :: FilePath -> IO (Maybe ImageSize)
readImageSize fp = imageSize `fmap` B.readFile fp
imageType :: ByteString -> Maybe ImageType
@@ -55,7 +61,7 @@ imageType img = case B.take 4 img of
"\xff\xd8\xff\xe0" -> return Jpeg
_ -> fail "Unknown image type"
-imageSize :: ByteString -> Maybe (Width,Height)
+imageSize :: ByteString -> Maybe ImageSize
imageSize img = do
t <- imageType img
case t of
@@ -63,35 +69,73 @@ imageSize img = do
Gif -> gifSize img
Jpeg -> jpegSize img
-pngSize :: ByteString -> Maybe (Width,Height)
+sizeInPixels :: ImageSize -> (Integer, Integer)
+sizeInPixels s = (pxX s, pxY s)
+
+sizeInPoints :: ImageSize -> (Integer, Integer)
+sizeInPoints s = (pxX s `div` dpiX s * 72, pxY s `div` dpiY s * 72)
+
+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"
- case map fromIntegral $ unpack $ B.take 8 rest' 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)
- _ -> fail "PNG parse error"
-
-gifSize :: ByteString -> Maybe (Width,Height)
+ 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)
+ _ -> fail "PNG parse error"
+ let (dpix, dpiy) = findpHYs rest''
+ return $ ImageSize { pxX = x, pxY = y, dpiX = dpix, dpiY = dpiy }
+
+findpHYs :: ByteString -> (Integer, Integer)
+findpHYs x =
+ if B.null x || "IDAT" `B.isPrefixOf` x
+ then (72,72) -- default, no pHYs
+ else if "pHYs" `B.isPrefixOf` x
+ then let [x1,x2,x3,x4,y1,y2,y3,y4,u] = map fromIntegral
+ $ unpack $ B.take 9 $ B.drop 4 x
+ factor = if u == 1 -- dots per meter
+ then \z -> z * 254 `div` 10000
+ else const 72
+ in ( factor $ (shift x1 24) + (shift x2 16) + (shift x3 8) + x4,
+ factor $ (shift y1 24) + (shift y2 16) + (shift y3 8) + y4 )
+ else findpHYs $ B.drop 1 x -- read another byte
+
+gifSize :: ByteString -> Maybe ImageSize
gifSize img = do
let (h, rest) = B.splitAt 6 img
guard $ h == "GIF87a" || h == "GIF89a"
case map fromIntegral $ unpack $ B.take 4 rest of
- [w2,w1,h2,h1] -> return (shift w1 8 + w2, shift h1 8 + h2)
+ [w2,w1,h2,h1] -> return ImageSize {
+ pxX = shift w1 8 + w2,
+ pxY = shift h1 8 + h2,
+ dpiX = 72,
+ dpiY = 72
+ }
_ -> fail "GIF parse error"
-jpegSize :: ByteString -> Maybe (Width,Height)
+jpegSize :: ByteString -> Maybe ImageSize
jpegSize img = do
- let (h, rest) = B.splitAt 2 img
- guard $ h == "\xff\xd8"
- findJpegLength rest
-
-findJpegLength :: ByteString -> Maybe (Width,Height)
-findJpegLength bs = do
+ let (hdr, rest) = B.splitAt 4 img
+ guard $ hdr == "\xff\xd8\xff\xe0"
+ guard $ B.length rest >= 14
+ let [dpiDensity,dpix1,dpix2,dpiy1,dpiy2] = map fromIntegral
+ $ unpack $ B.take 5 $ B.drop 9 $ rest
+ let factor = case dpiDensity of
+ 1 -> id
+ 2 -> \x -> (x * 254 `div` 10)
+ _ -> const 72
+ let dpix = factor (shift dpix1 8 + dpix2)
+ let dpiy = factor (shift dpiy1 8 + dpiy2)
+ (w,h) <- findJpegSize rest
+ return $ ImageSize { pxX = w, pxY = h, dpiX = dpix, dpiY = dpiy }
+
+findJpegSize :: ByteString -> Maybe (Integer,Integer)
+findJpegSize bs = do
let bs' = B.dropWhile (=='\xff') $ B.dropWhile (/='\xff') bs
case B.uncons bs' of
Just (c,bs'') | c >= '\xc0' && c <= '\xc3' -> do
@@ -103,7 +147,7 @@ findJpegLength bs = do
[c1,c2] -> do
let len = shift c1 8 + c2
-- skip variables
- findJpegLength $ B.drop len bs''
+ findJpegSize $ B.drop len bs''
_ -> fail "JPEG parse error"
Nothing -> fail "Did not find length record"
diff --git a/src/Text/Pandoc/Writers/ODT.hs b/src/Text/Pandoc/Writers/ODT.hs
index f5030e6d8..5c6f22ec6 100644
--- a/src/Text/Pandoc/Writers/ODT.hs
+++ b/src/Text/Pandoc/Writers/ODT.hs
@@ -37,7 +37,7 @@ import Codec.Archive.Zip
import System.Time
import Paths_pandoc ( getDataFileName )
import Text.Pandoc.Shared ( WriterOptions(..) )
-import Text.Pandoc.ImageSize ( readImageSize )
+import Text.Pandoc.ImageSize ( readImageSize, sizeInPoints )
import Text.Pandoc.MIME ( getMimeType )
import Text.Pandoc.Definition
import Text.Pandoc.Generic
@@ -104,11 +104,10 @@ transformPic :: FilePath -> IORef [Entry] -> Inline -> IO Inline
transformPic sourceDir entriesRef (Image lab (src,tit)) = do
let src' = unEscapeString src
mbSize <- readImageSize src'
- let pxToPoints px = px * 72 `div` 96
let tit' = case mbSize of
- Just (w,h) -> show (pxToPoints w) ++ "x" ++
- show (pxToPoints h)
- Nothing -> tit
+ Just s -> let (w,h) = sizeInPoints s
+ in show w ++ "x" ++ show h
+ Nothing -> tit
entries <- readIORef entriesRef
let newsrc = "Pictures/" ++ show (length entries) ++ takeExtension src'
catch (readEntry [] (sourceDir </> src') >>= \entry ->