Design of Arabic Diacritical Marks

Diacritical marks play a crucial role in meeting the criteria of usability of typographic text, such as: homogeneity, clarity and legibility. To change the diacritic of a letter in a word could completely change its semantic. The situation is very complicated with multilingual text. Indeed, the problem of design becomes more difficult by the presence of diacritics that come from various scripts; they are used for different purposes, and are controlled by various typographic rules. It is quite challenging to adapt rules from one script to another. This paper aims to study the placement and sizing of diacritical marks in Arabic script, with a comparison with the Latin's case. The Arabic script is cursive and runs from right-to-left; its criteria and rules are quite distinct from those of the Latin script. In the beginning, we compare the difficulty of processing diacritics in both scripts. After, we will study the limits of Latin resolution strategies when applied to Arabic. At the end, we propose an approach to resolve the problem for positioning and resizing diacritics. This strategy includes creating an Arabic font, designed in OpenType format, along with suitable justification in TEX.