If you have some symmetrical tiles, it is often hard to tell whether the tile was rotated or mirrored when it was placed. One can often be more computationally efficient than the other, and in those cases, you would prefer to adjust those tiles accordingly. Some way to look at your tile map layers, and tell their orientation and mirroring would be rather helpful in these cases, I think.
I can see how it would be useful, so feel free to open an issue about it on GitHub. It’s not something I’m likely to get around to though, since most people will have no use for it.
There is actually no reason why drawing flipped or rotated tiles would be slower on today’s hardware though (unless you can avoid the feature altogether, which would save a little CPU), so my main advice would be to look into why you need to do this kind of optimization in the first place.
Yes and no; it depends on what you choose your target hardware to be. If you want to run it on an Arduino, you might well care very much about this sort of optimization. Or maybe you’re doing a demo on original (NES, Genesis, whatever) hardware. The key question is probably whether or not you just want this to be a tool for creating good looking tile art, or whether you want it to be a tool fit for any use of tile based art. I would find the latter more useful, myself.
The answer to this question is easy, I want Tiled to be as useful as possible for current level editing needs. Of course that includes support for people still interested in targeting old console hardware or embedded devices without decent graphics chip. When I say “It’s not something I’m likely to get around to”, I’m not talking about my preference, but about the priority in relation to the amount of time I can afford to spend on Tiled.
If you want to help me get around to more features, or to raise the priority for some features beyond just asking for them, please consider becoming a patron. Of course, patches are welcome as well.