Adobe InDesign CS6 and ebooks, round 2

This is a continuation of Round 1, focusing on observations I made during my attempts to get InDesign to create an EPUB out of my test file.

EPUB oddities

Loss of chapter drops

[Screen capture of Adobe Digital Editions, showing how the chapter drop has been lost]

When converting to EPUB, all the chapter drops are lost. While this is in some sense expected, I expected that I could fix this by specifying “space before” in my paragraph styles, expecting it to be translated to margin-top during the export. That did not happen—chapter drops were still lost.

I was able to re-create the chapter drops by specifying “additional CSS,” but I will need to test the resulting EPUB on a real device some time.

[Chapter drop restored with additional CSS]

In fact almost all the formatting except font settings and leading have been lost during the export. A lot can probably be fixable at the CSS level, but that might be illusory as I don’t know what kind of CSS real EPUB reading devices support.

One other thing that bothered me: While the chapter drop can be restored with additional CSS, the amount of drop that I needed to specify did not seem to correlate to the leading. Since the two should be related in some way, some further investigation is needed.

Misrasterized outlined type

One reason why people outline type is to prevent complications in production. However, this does not seem to carry over to ebooks.

The following shows a simple mock-up of my test document’s cover page, showing the fish logo that the author of the text designed. My version of the logo is completely made up of type, but on the cover page it has been outlined.

[Screen capture of InDesign CS6, showing how the fish logo is supposed to look like]

Conversion to EPUB 2.1 turned the fish logo into a complete jumble:

[Screen capture of Adobe Digital Editions, showing how the fish logo has been misrasterized]

Not only has the first page not been rasterized (contrary to what the Export dialog would have me believe), it has incorrectly rasterized what it did actually rasterize: As you can see, not only is the horizontal alignment wrong, even the vertical spacing is wrong.

This is totally incomprehensible. Although the fish logo has been outlined and grouped, InDesign acted as if it had ungrouped the logo, centred everything, and ignored all the vertical spacing.

This suggests that InDesign is incapable of handling vector art correctly when exporting to EPUB.

Postscript: Rasterization bugs, xml:lang, and useless alternate texts

After this was posted I looked at the actual XHTML generated by InDesign, and what I saw gave me some hints as to what actually went wrong:

[Part of the generated XHTML. In the middle we see three img elements, with classes frame-1, frame-3, and frame-4 respectively, each enclosed by a div with a class of frame-2. The three enclosing divs are then in turn enclosed by an anonymous div which represented the group. We also see on the top that the body tag has the attribute of xml:lang='en-CA'.] We can make three observations here:

Note that InDesign has broken the fish logo into three, even though the three paths are grouped (by InDesign, by the way, as part of the Create Outlines process). In other words, if your vector art consists of distinct, non-overlapping compound paths (which is probably close to 100% of the time), InDesign will rasterize your art incorrectly when it exports to PDF. This is definitely an InDesign bug.
The xml:lang attribute has been correctly set to en-CA in the EPUB export. This is in stark contrast to the PDF export, where you have to post-process the PDF in Acrobat Pro to set the document language. InDesign’s failure to set the PDF language automatically is, I’d say, also obviously an InDesign bug.
Note that the alt tags for the three parts of the fish logo are set to their generated file names. This is, of course, unacceptable in any version of HTML, as these file names are meaningless both to text browser users and screen reader users. After making sure that the grouped object has a blank alt text and set to Artefact, the exported EPUB still contains these unacceptable alt texts. This, also, is obviously an InDesign bug.

We can only conclude that InDesign’s EPUB support is quite buggy and we will need to “get acquainted” with it in order to work around its many problems. It will be interesting to test how QuarkXPress performs with a similar test file.