I just ran across this bug in v2.1.1 while trying to use a single image of a flower petal rotated to draw a blooming flower, and wanted to add my voice to the choir.
I've only tried a 0.0f centery, and like Eiyeron, I am only seeing it at 90 and 180 degrees. 270 and 360 are fine. Special case-ing the wonky angles by inverting the centery from 0 to 1 alleviates the problem:
// C++ API bindings are calling `drawRotatedBitmap` from the C API under the hood.
petal.draw(bounds.getCenter().toInt(), 0.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 45.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 90.0f, 0.5f, 1.0f); // Whoops!
petal.draw(bounds.getCenter().toInt(), 135.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 180.0f, 0.5f, 1.0f); // Whoops!
petal.draw(bounds.getCenter().toInt(), 225.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 270.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 325.0f, 0.5f, 0.0f);
petal.draw(bounds.getCenter().toInt(), 360.0f, 0.5f, 0.0f);
Produces:
without special casing the same code produces this:
Out of curiosity I tried centery offsets of 0.9f, and 0.1f, both of which exhibit the same inversion behavior. I haven't bothered trying anything with centerx.