Tiled supports flipping and rotating tiles, but those tiles are not displayed at all in Slick. Tiled encodes this information in the Most significant bits of the Tile Id, so any Loader unaware of this will not find the Tiles.
I have patched Slick to read and correctly display flipped and rotated tiles:
File comment: Patch based against SVN revision 1560
FlipRotate.zip [1.25 KiB]
Downloaded 67 times
In some parts the code is not the cleanest, but it works.
Layer.getTileId still returns the Tile Id with the Flipping Bits set. Whether this is desirable needs to be discussed.
Implementation details: I decided not to cache the Flipping/Rotating booleans but to parse them out of the Id when the Tile needs to be rendered, because the performance gains would only be minimal, compared to a huge increase in memory usage.