Kobo Touch Displays Some SVG Images as Black Rectangles

[MikeWV]

According to github.com/kobolabs/epub-spec:

Sideloading for Testing Purposes

Kobo encourages the testing of content on all its reading platforms. However, sideloading is currently supported on eInk, Android and iOS. Here’s how to sideload content:

eInk

1. Connect the device to your computer via USB.
2. Find the drive on your computer in Finder or Windows Explorer.
3. Drag your ePub onto the device. To trigger the Kobo WebKit, change the file extension to “.kepub.epub”.

Under "Placing Images Properly," they state:

Kobo reading platforms support the core image types outlined in the IDPF spec. This includes JPG, PNG and GIF but not Scalable Vector Graphics (SVG), which are not supported on all reading platforms. (See the Support Grid.) PNG files are preferred over JPG.

Under "Scalable Vector Graphics (SVG)" they state:

SVG is partially supported across Kobo platforms. Thorough testing is advised for ePubs with SVG, particularly for text rendering. Content creators are advised to use the ePub switch element to provide fallback content. Refer to the support grid in this document or the test results for Kobo's reading platforms at ePubtest.org.

The support grid doesn't address SVG. The closest it comes it CSS animation. And the epubtest.org grid doesn't include SVG, either.

So changing the extension is the recommended means of testing but SVG images may or may not be rendered correctly or they may not be rendered at all. It would be nice if they were a little more specific about their SVG support.