From 878ab00233ec57270a60103b2b152f2257c40bae Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Thu, 2 Apr 2015 21:02:39 -0700
Subject: [PATCH] ImageSize: Added functions for converting between image
dimensions.
(mb21)
---
src/Text/Pandoc/ImageSize.hs | 153 +++++++++++++++++++++++++++++++----
1 file 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 }