pdfCalligraph: advanced typography

Your business is global, shouldn’t your documents be, too? The PDF format does not make it easy to support certain alphabets, but now, with the help of iText and pdfCalligraph, we are on our way to truly making PDF a global format.

The iText library was originally written in the context of Western European languages, and was only designed to handle left-to-right alphabetic scripts. However, the writing systems of the world can be much more complex and varied than just a sequence of letters without interaction. Supporting every type of writing system that humanity has developed is a tall order, but we strive to be a truly global company. As such, we are determined to respond to customer requests asking for any writing system. In response to this, we have begun our journey into advanced typography with pdfCalligraph.

pdfCalligraph is an add-on module for iText 7, designed to seamlessly handle any kind of advanced shaping operations when writing textual content to a PDF file. Its main function is to correctly render complex writing systems such as the right-to-left Hebrew and Arabic scripts, and the various writing systems of the Indian subcontinent and its surroundings. In addition, it can also handle kerning and other optional features that can be provided by certain fonts for other alphabets.

In this paper, we first provide a number of cursory introductions: we’ll start out by exploring the murky history of encoding standards for digital text, and then go into some detail about how the Arabic and Brahmic alphabets are structured. Afterwards, we will discuss the problems those writing systems pose in the PDF standard, and the solutions to these problems provided by iText 7’s add-on pdfCalligraph.