נעם טרקטינסקי

Bidirectional (BiDi) user interfaces involve interface elements that appear in opposite directions - right-to-left (RTL) and left-to-right (LTR). In many cases, the appropriate direction is clear. However, interaction designers of BiDi systems and products must often decide the direction of UI elements when both RTL and LTR are plausible. We introduce the concept of Optimal UI Item Direction (OUIID) and a process for selecting directionality that balances multiple goals, including effectiveness, efficiency, satisfaction, and design consistency. We evaluate OUIID on 30 common UI items with BiDi users, using multiple indicators. The results show no universally dominant direction; optimal choices depend on the use context, user familiarity, and the weighting of the design goals. We demonstrate a multi-objective optimization approach that consolidates mixed results into actionable recommendations, providing a practitioner tool for applying OUIID when only a subset of measures is available. We discuss implications for context-sensitive, evidence-guided BiDi design systems.