How do you get the duration of a GIF?

[natanfudge]

Hey, I'm thinking of displaying a duration indicator at the bottom of the screen when displaying a GIF. However, I couldn't find any way to actually get this information from the Coil API. I understand that you're supposed to sum the delays of all frames, but how do you actually get the frame delays in the Coil context?

[colinrtwhite]

I don't think it's possible to get the GIF duration at the moment. To add this feature ImageDecoder would need to expose that info as well.

[natanfudge]

@colinrtwhite
Yes, it seems that once it goes through ImageDecoder that information is lost. Maybe there's a way to gain access to the ByteArray/InputStream of the gif as it was received from the network, and parse the duration information myself, using a separate API? It would be slower, but it would get the job done (and this is a very important feature for me!)

[colinrtwhite]

Your best bet would be to write a custom Decoder.Factory that delegates to ImageDecoderDecoder.Factory/GifDecoder.Factory then reads the duration from the ImageSource if necessary.

[natanfudge]

Using @colinrtwhite advice and the Metadata Extractor Library, I've implemented this feature. For those looking for the same thing, I've posted a full gist of the code: https://gist.github.com/natanfudge/709c6a86097da4162fa47074e632317b.

Note it does use some reflection to access internal Coil classes, it would be nice if you could find an alternative!