diff options
| -rw-r--r-- | src/Text/Pandoc/ImageSize.hs | 153 |
1 files changed, 138 insertions, 15 deletions
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs index 09c1dd443..7489afc8e 100644 --- a/src/Text/Pandoc/ImageSize.hs +++ b/src/Text/Pandoc/ImageSize.hs @@ -29,17 +29,37 @@ Portability : portable Functions for determining the size of a PNG, JPEG, or GIF image. -} -module Text.Pandoc.ImageSize ( ImageType(..), imageType, imageSize, - sizeInPixels, sizeInPoints ) where +module Text.Pandoc.ImageSize ( ImageType(..) + , imageType + , imageSize + , sizeInPixels + , sizeInPoints + , desiredSizeInPoints + , Dimension(..) + , Direction(..) + , dimension + , inInch + , inPoints + , numUnit + , showInInch + , showInPixel + , showFl + ) where import Data.ByteString (ByteString, unpack) import qualified Data.ByteString.Char8 as B import qualified Data.ByteString.Lazy as BL +import Data.Char (isDigit) import Control.Applicative import Control.Monad import Data.Bits import Data.Binary import Data.Binary.Get import Text.Pandoc.Shared (safeRead, hush) +import Data.Default (Default) +import Numeric (showFFloat) +import Text.Read (readMaybe) +import Text.Pandoc.Definition +import Text.Pandoc.Options import qualified Data.Map as M import Text.Pandoc.Compat.Except import Control.Monad.Trans @@ -49,6 +69,20 @@ import Data.Maybe (fromMaybe) -- algorithms borrowed from wwwis.pl data ImageType = Png | Gif | Jpeg | Pdf | Eps deriving Show +data Direction = Width | Height +instance Show Direction where + show Width = "width" + show Height = "height" + +data Dimension = Pixel Integer + | Centimeter Double + | Inch Double + | Percent Double +instance Show Dimension where + show (Pixel a) = show a ++ "px" + show (Centimeter a) = showFl a ++ "cm" + show (Inch a) = showFl a ++ "in" + show (Percent a) = show a ++ "%" data ImageSize = ImageSize{ pxX :: Integer @@ -56,7 +90,11 @@ data ImageSize = ImageSize{ , dpiX :: Integer , dpiY :: Integer } deriving (Read, Show, Eq) +instance Default ImageSize where + def = ImageSize 300 200 72 72 +showFl :: (RealFloat a) => a -> String +showFl a = showFFloat (Just 5) a "" imageType :: ByteString -> Maybe ImageType imageType img = case B.take 4 img of @@ -88,8 +126,93 @@ defaultSize = (72, 72) sizeInPixels :: ImageSize -> (Integer, Integer) sizeInPixels s = (pxX s, pxY s) -sizeInPoints :: ImageSize -> (Integer, Integer) -sizeInPoints s = (pxX s * 72 `div` dpiX s, pxY s * 72 `div` dpiY s) +-- | Calculate (height, width) in points using the image file's dpi metadata, +-- using 72 Points == 1 Inch. +sizeInPoints :: ImageSize -> (Double, Double) +sizeInPoints s = (pxXf * 72 / dpiXf, pxYf * 72 / dpiYf) + where + pxXf = fromIntegral $ pxX s + pxYf = fromIntegral $ pxY s + dpiXf = fromIntegral $ dpiX s + dpiYf = fromIntegral $ dpiY s + +-- | Calculate (height, width) in points, considering the desired dimensions in the +-- attribute, while falling back on the image file's dpi metadata if no dimensions +-- are specified in the attribute (or only dimensions in percentages). +desiredSizeInPoints :: WriterOptions -> Attr -> ImageSize -> (Double, Double) +desiredSizeInPoints opts attr s = + case (getDim Width, getDim Height) of + (Just w, Just h) -> (w, h) + (Just w, Nothing) -> (w, w / ratio) + (Nothing, Just h) -> (h * ratio, h) + (Nothing, Nothing) -> sizeInPoints s + where + ratio = fromIntegral (pxX s) / fromIntegral (pxY s) + getDim dir = case (dimension dir attr) of + Just (Percent _) -> Nothing + Just dim -> Just $ inPoints opts dim + Nothing -> Nothing + +inPoints :: WriterOptions -> Dimension -> Double +inPoints opts dim = 72 * inInch opts dim + +inInch :: WriterOptions -> Dimension -> Double +inInch opts dim = + case dim of + (Pixel a) -> fromIntegral a / (fromIntegral $ writerDpi opts) + (Centimeter a) -> a * 0.3937007874 + (Inch a) -> a + (Percent _) -> 0 + +-- | Convert a Dimension to a String denoting its equivalent in inches, for example "2.00000". +-- Note: Dimensions in percentages are converted to the empty string. +showInInch :: WriterOptions -> Dimension -> String +showInInch _ (Percent _) = "" +showInInch opts dim = showFl $ inInch opts dim + +-- | Convert a Dimension to a String denoting its equivalent in pixels, for example "600". +-- Note: Dimensions in percentages are converted to the empty string. +showInPixel :: WriterOptions -> Dimension -> String +showInPixel opts dim = + case dim of + (Pixel a) -> show a + (Centimeter a) -> show (floor $ dpi * a * 0.3937007874 :: Int) + (Inch a) -> show (floor $ dpi * a :: Int) + (Percent _) -> "" + where + dpi = fromIntegral $ writerDpi opts + +-- | Maybe split a string into a leading number and trailing unit, e.g. "3cm" to Just (3.0, "cm") +numUnit :: String -> Maybe (Double, String) +numUnit s = + let (nums, unit) = span (\c -> isDigit c || ('.'==c)) s + in case readMaybe nums of + Just n -> Just (n, unit) + Nothing -> Nothing + +-- | Read a Dimension from an Attr attribute. +-- `dimension Width attr` might return `Just (Pixel 3)` or for example `Just (Centimeter 2.0)`, etc. +dimension :: Direction -> Attr -> Maybe Dimension +dimension dir (_, _, kvs) = + case dir of + Width -> extractDim "width" + Height -> extractDim "height" + where + extractDim key = + case lookup key kvs of + Just str -> + case numUnit str of + Just (num, unit) -> toDim num unit + Nothing -> Nothing + Nothing -> Nothing + toDim a "cm" = Just $ Centimeter a + toDim a "mm" = Just $ Centimeter (a / 10) + toDim a "in" = Just $ Inch a + toDim a "inch" = Just $ Inch a + toDim a "%" = Just $ Percent a + toDim a "px" = Just $ Pixel (floor a::Integer) + toDim a "" = Just $ Pixel (floor a::Integer) + toDim _ _ = Nothing epsSize :: ByteString -> Maybe ImageSize epsSize img = do @@ -279,21 +402,21 @@ exifHeader hdr = do return (tag, payload) entries <- sequence $ replicate (fromIntegral numentries) ifdEntry subentries <- case lookup ExifOffset entries of - Just (UnsignedLong offset) -> do + Just (UnsignedLong offset') -> do pos <- lift bytesRead - lift $ skip (fromIntegral offset - (fromIntegral pos - 8)) + lift $ skip (fromIntegral offset' - (fromIntegral pos - 8)) numsubentries <- lift getWord16 sequence $ replicate (fromIntegral numsubentries) ifdEntry _ -> return [] let allentries = entries ++ subentries - (width, height) <- case (lookup ExifImageWidth allentries, - lookup ExifImageHeight allentries) of - (Just (UnsignedLong w), Just (UnsignedLong h)) -> - return (fromIntegral w, fromIntegral h) - _ -> return defaultSize - -- we return a default width and height when - -- the exif header doesn't contain these + (wdth, hght) <- case (lookup ExifImageWidth allentries, + lookup ExifImageHeight allentries) of + (Just (UnsignedLong w), Just (UnsignedLong h)) -> + return (fromIntegral w, fromIntegral h) + _ -> return defaultSize + -- we return a default width and height when + -- the exif header doesn't contain these let resfactor = case lookup ResolutionUnit allentries of Just (UnsignedShort 1) -> (100 / 254) _ -> 1 @@ -302,8 +425,8 @@ exifHeader hdr = do let yres = maybe 72 (\(UnsignedRational x) -> floor $ x * resfactor) $ lookup YResolution allentries return $ ImageSize{ - pxX = width - , pxY = height + pxX = wdth + , pxY = hght , dpiX = xres , dpiY = yres } |