Typesetting variable-sized curved symbols

The main goal of this contribution is to present a program that allows the composition of variable-sized curved symbols such as those occurring in mathematics. This application, called CurExt, extends the capabilities of the well-known system TEX designed by D. E. Knuth for typesetting. Big delimiters, such as brackets, or special curved symbols, such as the Arabic mathematical symbol of sum, can be built automatically according to the size and the shape of the concerned mathematical expression. CurExt will make it possible to stretch Arabic letters according to calligraphic rules in order to draw the kashida. It follows a useful tool for justifying texts written with Arabic alphabet. Unlike in Latin alphabet based writing, where the justication is done through inserting small blanks among characters, cursive writing lls in the space between characters with the kashida.