Italics drawing convention


Please, take a look at these images and tell me what convention should I stick to while creating italics.

  1. Red nodes not at extremes, but parallel to the italic angle. Blue nodes also parallel. All nodes should be dekinked - this causes problem using components for endings.

  2. Green nodes are at extremes now, but Blue nodes should be dekinked.

  3. Green nodes at extremes, nodes at a middle of a glyph are gone.

Do all these rules apply to italics? It’s quite difficult to draw in such way.

Technically, 2 is the best. But you can have both inflection points and extreme points added automatically at export time, if you use the appropriate custom parameters. That way, you can pretty much draw whichever way you find best.

If you have inflections added at export time, you save a lot of dekinking work:

I don’t think that inflections are a problem in this case. So I would try to do the third option.

Thank you guys. That clears a lot.

But, do inflection points have a significant impact on generated font? In other words why do I should put inflection points?

And do these points added with a custom parameter during font export alter a glyphs’ shapes? I understand that dekinks are no longer a problem because it is done after interpolation?

There might be some (old) rasterizers that might have problems with it. I never had a problem with it.

A PS path segment that inflects (=bends both ways) can be problematic for subsequent transformations, like path offsetting. There is no mathematically sound way to draw a parallel, for instance. Now, most tools that do stuff with paths, secretly add extra nodes to the path.

Granted, in most use cases of a font, this is not really a problem.

The path alteration is usually very small. But it could indeed be problematic for small inflections if you have a grid step of 1. Take cupped serifs, a place where you want to keep the inflection (necessary for flex hints). A threshold is on my to-do list for this filter.