Uneven lowercase at low resolution

Igor Petrovic

Here is the screenshot of the typeface I am working on. At 19px size and lower, lowercase start to "dance". Tops and bottoms are uneven, like they have a different baseline/x-height. I don't know what's the reason, because I can't recall such situations earlier. I defined the zones in a classic manner, and did PS autohinting (with manual hint adjustment in addition). Even tried to push extreme nodes in zones (thought it might be a coordinate rounding problem). I would appreciate much any input on this, thanks!

Viktor Rubenko

Igor Petrovic said:

At 19px size and lower, lowercase start to "dance". 

Something is wrong with your alignment zones, I guess.

Malcolm Wooden

You have said that you set your zones but there is obviously something going wrong here. Is the output CFF(OTF) or TTF? Someone probably needs to check your source file for you so perhaps you could make the file available here.

Igor Petrovic

Many thanks for your answers. Yes, now I see it isn't about displaying at the small size, but the problem with zones in general. I am not sure what's going on, probably a software bug. I will troubleshoot in detail tomorrow and see if I can find a solution (and back here if not) Thanks!

Thomas Phinney

You don't mention what tool you are using to do the PS autohinting. Nor do you say what OS and version you are previewing the font on.

That makes it hard to give specific guidance. I concur with Malcolm that there might be something very wrong with your zones. (Then again, if you are viewing the font on macOS, your hinting would be irrelevant at these sizes.)

Igor Petrovic

@Thomas Phinney Sorry, I forgot to mention that. I am using FontLab VI (64-bit) at Windows 7 (64-bit). Yes, something strange is going on with the zones definitely. Seems that my custom defined zones are ignored, because when I open exported OTF back in FL I just see the baseline zone. 

The other problem I have is that checkboxes don't work (nor in Font Info or Exporting Profiles). I wrote on FL forum earlier about that, but for some reason, just a few of us can reproduce that problem (it got official bug ID number)

I didn't know this problem about zones is a bug, otherwise, I would post on FL forum.

Thanks! 

Igor Petrovic

UPDATE: I tested today behavior in Windows 10 (on my friend's machine), and checkboxes and zones definition worked fine (so that part of the problem is due to Windows 7). However, even when my zones were defined as I wanted, the problem with uneven lowercase persisted. 

In the meantime, I realized that I actually can define zones and export the font with such defined zones, but if I save the project/close/open it again, zone definition is lost.

So here you can download the source project (without properly defined zones, because I can't save them as mentioned above), the screenshot how I intended to define zones as well exported OTF (with proper zones, but with the "dancing" lowercase):

https://www.dropbox.com/s/fsq3en9qfm3geho/Zoran Source Files.zip?dl=0

Thanks!

notdef

Note that the baseline zone should actually belong to the primary (top) alignment zones.

Viktor Rubenko

@Igor Petrovic

Don't know how good FL5 is in reverse engineering of PS hints, but it shows me this:

So, if we add top vertical zone, it looks good:

Igor Petrovic

@Frode Thanks for the answer. I am not sure about that, because it's defined as a bottom zone by default in FL VI (and it naturally is a bottom zone). 

@Viktor Rubenko It works, many thanks! So the problem wasn't with the alignment zones but with glyph level PS hints.

The only thing is that now I am not sure I completely understand "glyph level PS hint" as a concept, but I will post that as a separate question, because I think it's an important topic that shouldn't be hidden in this thread. 

Thank you all!

John Hudson

I am not sure about that, because it's defined as a bottom zone by default in FL VI (and it naturally is a bottom zone). 

FontLab VI uses a higher level interface for setting alignment zones, which is shared by PS/CFF and TTF hinting models. When compiled to a PS/CFF font, the baseline alignment zone should get written to the top dictionary; this is a legacy of the initial Type 1 hinting implementation.

Igor Petrovic

John Hudson said:

I am not sure about that, because it's defined as a bottom zone by default in FL VI (and it naturally is a bottom zone). 

FontLab VI uses a higher level interface for setting alignment zones, which is shared by PS/CFF and TTF hinting models. When compiled to a PS/CFF font, the baseline alignment zone should get written to the top dictionary; this is a legacy of the initial Type 1 hinting implementation.

What does it mean in effect, is it ok to keep it as a bottom zone (which is default) in Font Info dialogue of FL VI? 

John Hudson

I expect so, but I've only recently started using FLVI, and am not familiar with all aspects of it.

Igor Petrovic

@John Hudson Got it, thanks!

Thomas Phinney

Yes