first post of the KF8 Fixed Layout template, I had wanted to create a text box with a semi-transparent background fill, but left it out due to the fact that the opacity value in the CSS magTarget entity applies to all content included in the mag region, text included. Thus, as presented by Amazon, there is no real use at all for the opacity tag.
However, as I postulated previously, it should be possible to create a lightbox that is sized so as to be contained entirely within the magnified region, rather than without. As you can see by the image at the left, I have done just that. The newly yet-again once more updated template now includes an example of this usage on Page 3, along with the standard lightbox style.
My primary reason for wanting to include this feature is that it allows the magnified text box to include a background texture that exactly matches the actual content on the page, while being completely readable, as opposed to an opaque fill or inserted image that at best can only approximate the page content, and only if you embed a different background image for each and every page (or have pages that vary only slightly in hue and tone); the only other option is to use something highly contrasting and not bother color matching at all, such as a plain white fill. Initially I inserted a parchment backdrop behind my zoomed text, but I found that too distracting for my taste, and wanted something more subdued and subtle. I also tried a slightly desaturated image of the background texture sans text, but this was not entirely satisfactory, as it increased the overall file size unnecessarily by requiring multiple versions of every background image. This is the solution I was after.
You can download the latest update of the .epub and .mobi files from the post linked to above, and view the code to see how this was done. It's not the cleanest code I've ever seen, mind you, and I'm sure I could have organized the stylesheet better, but what's necessary is all in there. I'll probably refine it a bit later. The new code is for the most part added to the bottom and kept together, rather than intermingling it with the rest, so as not to be any more confusing than need be. I'm nearly done with the image zoom portion of the KF8 fixed layout tutorial, and hope to post it later today if all goes well. Of course, I now have to add a new section to it in which I explain the elements of this new functionality. After this I'm swearing off any further tinkering (at least for the time being).