Research on visual size and visual alignment optimization of icon set design*

The industry's relevant guidelines on icon design point out that in the design of icon sets, designers should adjust the size and position of each icon, instead of simply unifying the size and position by icon bounding box, to ensure consistency in visual size and visual alignment. However, existing guidelines provide vague answers on specifically adjusting different icons, leaving designers to rely on subjective experience and intuition for adjustments. To explore the general pattern of visual size and alignment between different icons, we first measured the visual size and alignment of different icons through subjective experiments, analyzed the data to find the influencing factors. Next, we constructed a visual size optimization model composed of these factors and proposed an optimization method based on the reference square. Then, we measured the difference between icons' visual alignment and bounding box alignment through experiments. Finally, we used expert evaluation to test the model's effectiveness in visual size consistency. We have reached the following conclusions: (1) For icons with the same convex hull, the perceived visual size is consistent; (2) To unify the icon visual size using a reference square as the standard, there are two factors affecting the visual size adjustment: the convex hull area of the icon and the convex hull area outside the bounds of the reference square. (3) The visual size optimization model helps slightly improve the visual alignment consistency of icons. These conclusions and the visual size optimization model contribute to establishing more rigorous icon design standards and developing plugins to enhance the quality and efficiency of icon design.