Connected Cursive Handwriting Fonts, Part 1: In Context
Context is everything! Well, maybe not everything, but it can sure change the meaning of things.
Fonts are no exception. Font selection can often change the meaning of written words, and even a different glyph within a word can affect a reader's response. A pay-up-or-else demand letter would lose its impact if written in a casual design like the Mistral® font, and who would think of sending wedding invitations using the Times New Roman® face? In connected cursive handwriting fonts, the context of the surrounding characters is crucial. But how we're supposed to write is significantly different from how we actually write. Below are Schoolhouse vLetter, Inc., based on the OpenType® Pro format. These fonts are used to help teach handwriting in schools.
Connected cursive handwriting can evoke a personal intimacy not possible with printed glyphs. The single flowing line forming cursive letters seems to open a window to the writer's stream of consciousness. The cursive letters appear to morph from one form to another to assure a contiguous flow. Each character needs to be formed differently depending upon the preceding character – hence the context. But many problems need to be solved to create a realistic-looking personal handwriting font.
For example, just obtaining a handwriting sample seems to be an easy task. But if the finished font is to be contextual, many variations of each character will be needed. Plus the sample words must be quick and easy to draw; otherwise, pauses and hesitations will make the handwriting appear jerky. And to create the outlines needed in a PostScript® or TrueType® font, the form needs to be scanned to create a bitmap first. So the quality of the handwritten lines is important – ballpoint pens or pencils can create nothing but headaches! Fortunately, handwriting glyphs don't have to be as perfectly formed as glyphs in an "engineered" font. In fact, if handwritten glyphs were too perfect, it wouldn't look like handwriting! But the connections need to be perfect.
And that's just the tip of the iceberg in making a connected cursive handwriting font. More difficult mathematical and coding challenges still loom, such as making sure the connections from character to character line up without adversely affecting the "personality" of the handwriting. Or, that the slope of the outlines matches to make the transition between glyphs appear seamless. Or, that the width of the outline at the joints is always the same, regardless of the pen pressure used in the original sample.
Jumping all those hurdles and more will be the subject of a future posting. But even before thinking of those "minor" difficulties, a process is needed to solve the fundamental problem of how to provide the simulation of a free-flowing contextual stream of characters that are to be represented on a computer or in print.
Fortunately, system-level OpenType contextual alternative technology is now accessible through applications for both Mac® and Windows® systems, and it can now provide automated glyph substitution based on contextual rules.
Prior to Apple Advanced Typography and OpenType, one could manually select a glyph from a "palette" of alternate glyphs, or switch to an alternative character font. Or do what vLetter did in the early 1990s by coding the contextual alternative logic into a PostScript 3 font – which Type 1 fonts don't allow. Or later, by providing a conversion utility or an application toolbar button to batch-convert selected text into an appropriate set of TrueType glyphs.
Now, OpenType contextual alternatives provide a more complete way to provide the contextual rules required to enable the automatic glyph substitution needed to form a connected cursive word. Among the many possible ways to simulate connected cursive handwriting using a font, vLetter categorizes character glyphs into groups depending on their trailing ligature connection. Then all that's needed is a glyph variation of each of the characters with a leading ligature that matches each trailing ligature type.
For U.S. English, 26 glyphs are needed for each trailing ligature type – one for each lowercase letter of the alphabet. The more types of ligatures used, the more realistic and accurate the font is to the original handwriting. This particular technique has been in use by vLetter for decades and is covered in vLetter proprietary technology and patents.
For example, if the letter "r" follows the letter "o", then the form of the "r" glyph will be chosen so that its leading ligature matches the trailing ligature of the "o", as shown below using my handwriting font. There are "r" glyphs in the font that match all the potential trailing ligature types, just as there are for all the other characters.
The types of contextual replacements are determined by how many glyphs need to be replaced and how many replacement glyphs are needed. Usually, when looking at a potential glyph that might need replacement, the type of connection to the preceding character will determine the particular replacement glyph. But sometimes multiple glyphs are needed, or a new glyph needs to be inserted between two glyphs, or a replacement is made depending on the next character, such as what happens when an apostrophe is needed between joined letters in a contraction.
Of course, the lowercase connections (or disconnections, depending on whether or not a particular character is connected) are only the beginning. Numerals, capitals, punctuation and even whitespace characters need contextual definitions, too. Additionally, some common letter combinations have a unique character (pun intended) and could have interesting ligature substitutions. Examples include the common words "and," and "the," plus some common double letter combinations like "oo," "tt," "ll," and "ss."
Since everyone's handwriting is different, all the rules that make up the contextual substitutions are different for each handwriting font. When I write a lowercase "s" at the beginning of a word, I use a block printed disconnected character. But my other lowercase "s"s connect at the baseline. Here's an example of my handwriting of the word, "subsystems."
Creating fonts from sources such as personal letters and correspondence is especially difficult, due to the lack of connection variations. Often, there are not enough samples in just a single manuscript. If multiple documents are used, then often the condition of other papers could be more degenerated, or perhaps a different pen could have been used. But that's a subject for a future posting.