performance tuning: prefer asynchronous Pretty.formatted, which actually takes longer than Command.rich_text (see also 97964515a676, where Pretty.formatted was on the GUI thread, maybe for the sake of java.awt.FontMetrics at that time);

The ceillog2 function (thanks to Manuel Eberl), replacing two copies of Ceil_Log2

merged

merged

clarified signature: avoid pointless alias (see also c82a1620b274 and 22aeec526ffd);

clarified signature;

tuned GUI: avoid wasting space with proportional fonts;