The impact of multidirectional text typography on text readability in word clouds

Word clouds are an essential tool for text visualization, and the readability of word clouds significantly affects the reading comprehension of users. Consequently, this study investigates the influence of text typography direction and font size in word clouds on their readability. Besides, The study assesses how text typography affects the readability of information presented in word clouds through a combination of objective reading performance metrics and subjective evaluations. Objective reading performance is measured through a word search task, whereas subjective evaluations include three metrics: readability, fatigue, as well as aesthetic appeal, assessed employing a 9-level Likert scale questionnaire. Participating in all three experiments were 120 individuals and the independent variables were the direction and number of text typography directions and font size. The study determined that word clouds with horizontal typography exhibit remarkably higher reading search accuracy, readability scores, and fatigue scores in comparison to word clouds with vertical and diagonal typography. Furthermore, more text directions included in word clouds result in a significant decrease in reading search accuracy, reading ease scores, and fatigue scores. Additionally, the font size notably influences the legibility of text displayed in word clouds, and yet there is no substantial interaction effect between font size and direction on the readability of word clouds. Accordingly, the study draws the following conclusions. In the first place, the readability of word clouds with horizontal typography text is considerably higher than that of word clouds with vertical and diagonal typography text. Second, an increase in text typography directions results in a substantial decrease in readability. Third, font size seriously influences the readability of text, with larger font sizes contributing to higher readability on the word cloud. Fourth, the text typography direction and the number of text typography directions included lacking a substantial influence on the aesthetic appeal of word clouds. This research can be adopted to optimize the layout design of word clouds. Besides, the findings of this study have wide applications in multi-directional text typography scenarios, including graphic design, human–computer interaction, and information visualization.