EPUB writer: Use svg tag wrapper for cover image.

In addition, the code generating the image has been moved
to the template, to make it more customizable.

Those who use custom EPUB templates will need to adjust their
templates, adding the code to generate the cover image.
(Previously this was just inserted into 'body'.)

Closes #5643.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Writers/EPUB.hs b/src/Text/Pandoc/Writers/EPUB.hs
index 82b6e8221..fdcab1442 100644
--- a/src/Text/Pandoc/Writers/EPUB.hs
+++ b/src/Text/Pandoc/Writers/EPUB.hs
@@ -41,6 +41,7 @@ import qualified Text.Pandoc.Class as P
 import Data.Time
 import Text.Pandoc.Definition
 import Text.Pandoc.Error
+import Text.Pandoc.ImageSize
 import Text.Pandoc.Logging
 import Text.Pandoc.MIME (MimeType, extensionFromMimeType, getMimeType)
 import Text.Pandoc.Options (EPUBVersion (..), HTMLMathMethod (..),
@@ -450,14 +451,23 @@ pandocToEPUB version opts doc = do
                      Nothing   -> return ([],[])
                      Just img  -> do
                        let coverImage = takeFileName img
+                       imgContent <- lift $ P.readFileLazy img
+                       (coverImageWidth, coverImageHeight) <-
+                             case imageSize opts' (B.toStrict imgContent) of
+                               Right sz  -> return $ sizeInPixels sz
+                               Left err' -> (0, 0) <$ report
+                                 (CouldNotDetermineImageSize img err')
                        cpContent <- lift $ writeHtml
                             opts'{ writerVariables =
                                     ("coverpage","true"):
                                     ("pagetitle",
                                        escapeStringForXML plainTitle):
+                                    ("cover-image", coverImage):
+                                    ("cover-image-width", show coverImageWidth):
+                                    ("cover-image-height",
+                                       show coverImageHeight):
                                      cssvars True ++ vars }
-                            (Pandoc meta [RawBlock (Format "html") $ "<div id=\"cover-image\">\n<img src=\"../media/" ++ coverImage ++ "\" alt=\"cover image\" />\n</div>"])
-                       imgContent <- lift $ P.readFileLazy img
+                            (Pandoc meta [])
                        coverEntry <- mkEntry "text/cover.xhtml" cpContent
                        coverImageEntry <- mkEntry ("media/" ++ coverImage)
                                              imgContent