I was curious about how G'MIC rounds at clipping boundaries; e.g., when saving the floating-point buffer to an integer PNG. In the stress test below, the command yields a PNG within the range of 1-255. If we remove one
9 digit from each value, the range shifts to 0-254.
gmic (.99999999,254.999999) -o tst.png tst.png
I guess, in practical terms, this doesn't mean all that much. It is just that over time, there would be a clipping creep in the shadows in saves or in environments that aren't by default floating-point.