Hi,
My book was designed in PubCoder back in 2015-6. It was originally designed for tablets (iPads and such), hence, the base resolution was 1024x768 (aspect ratio 4:3). In renditions of 16:9, the top and bottom were cropped. I made sure nothing important is cropped, though.
These days I'm bringing it back to life. I want it to work on modern phones, but nowadays some phone's aspect ratio is 20:9, and now it crops too much.
I thought of adding a new rendition - 20:9, and change the backgrounds in this rendition to new, wider images in which I'll add some background on both sides, not a big deal (in most pages).
The problem is that when I use these backgrounds, none of the overlaying/animations fit. Everything becomes too big and out of place, because the size adaptation is done in the wrong direction, or something like that.
If I keep the app as is, I get white strips on both sides, in 20:9 phones.
My questions are:

1. Is there some trick to use wider images when the base is 1024x768, or do I have to start all over with wider backgrounds?
2. If I keep it as is, how can I set the side strips to black and not white?

Thanks for reading such a long post, and for your help!
Ranco

anyone?
No answer, even for item#2?

got it, thanks