From 39153ea6e2a77604e3302c5591fbb65496c3457a Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Mon, 14 Dec 2020 09:39:07 -0800
Subject: [PATCH] ImageSize: use exif width and height when available.
After the move to JuicyPixels, we were getting incorrect
width and heigh information for some images (see #6936, test-3.jpg).
The correct information was encoded in Exif tags that
JuicyPixels seemed to ignore. So we check these first
before looking at the Width and Height identified by
JuicyPixels.
Closes #6936.
---
src/Text/Pandoc/ImageSize.hs | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs
index 665a94690..9ce5c668d 100644
--- a/src/Text/Pandoc/ImageSize.hs
+++ b/src/Text/Pandoc/ImageSize.hs
@@ -50,6 +50,7 @@ import qualified Data.Text.Encoding as TE
import Control.Applicative
import qualified Data.Attoparsec.ByteString.Char8 as A
import qualified Codec.Picture.Metadata as Metadata
+import qualified Codec.Picture.Metadata.Exif as Exif
import Codec.Picture (decodeImageWithMetadata)
-- quick and dirty functions to get image sizes
@@ -300,8 +301,16 @@ getSize img =
Left e -> Left (T.pack e)
Right (_, meta) -> do
pxx <- maybe (Left "Could not determine width") Right $
+ -- first look for exif image width, then width
+ (Metadata.lookup
+ (Metadata.Exif (Exif.TagUnknown 0xA002)) meta >>=
+ exifDataToWord) <|>
Metadata.lookup Metadata.Width meta
pxy <- maybe (Left "Could not determine height") Right $
+ -- first look for exif image height, then height
+ (Metadata.lookup
+ (Metadata.Exif (Exif.TagUnknown 0xA003)) meta >>=
+ exifDataToWord) <|>
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
@@ -310,6 +319,10 @@ getSize img =
, pxY = fromIntegral pxy
, dpiX = fromIntegral dpix
, dpiY = fromIntegral dpiy }
+ where
+ exifDataToWord (Exif.ExifLong x) = Just $ fromIntegral x
+ exifDataToWord (Exif.ExifShort x) = Just $ fromIntegral x
+ exifDataToWord _ = Nothing
svgSize :: WriterOptions -> ByteString -> Maybe ImageSize