Interpolation - Instance preview and output have different results

Glyphs
21

For me, the last remaining niggle is that the preview pane doesn’t show accurately the instances when a glyph with brace layers is used as a component.

It instead shows the glyph as if the brace layers didn’t exist:

http://cl.ly/image/2y2c17242d2m/Screen%20Shot%202015-01-27%20at%2012.00.58%20am.png

Generated font files/instances are correct.

22

I’ll have a look.

23

I’m still running into this problem, though it’s subtler (and therefore more devious!) then before.

For instance, let’s say I’m working on my /d with two masters — Hairline and Bold — and I’ve inserted a brace layer in the middle to make sure the thinning near the joins necessary in the Bold doesn’t reach too far down to the light weights. So far, so good. Even glyphs that use /d as a component respect this brace layer when I view interpolated instances in the Preview.

However! When testing my exported fonts on Pablo Impallari’s page, I stumbled across this gem:

This is supposed to be a /dcroat. It looked good in Glyphs, but the stroke is misplaced in the exported font. Turns out I built the brace layer for /d before worrying about the placement of the center anchor used by the bar, so while that anchor is correctly placed in both normal masters, it sits in the counter in the brace layer. The fact that this doesn’t show up in the interpolated Preview tells me the latter is not aware of the anchor placement in the brace layer.

Another, and perhaps related, bug is that sometimes the interpolated Preview gets «stuck» with a bad interpolation even after I’ve fixed the path order:

Screen Shot 2016-06-27 at 22.45.49.png734×1130 80.9 KB

As you can see, the masters are compatible, but the interpolated instance in Preview is clearly confusing some paths with each other. There are no brace or bracket layers involved here. Actually, most other interpolated instances looked good when I checked them out (presumably they were generated on the spot?), but I found it hard to get this particular instance unstuck.

24

I fixed the first problem:

Screenshot.png920×412 27.2 KB

What did you do when it got stuck? What function did you use?

25

Sorry, I don’t remember.

26

One more thing about brace layers: When I copy a brace layer for backup, it doesn’t unbold itself like layers usually do. In fact, Glyphs might be mistakenly using the copy as the active brace layer…

27

The Instance Preview in the Font Info > Instances doesn’t represent a transformation filter, too. I got a simple OffsetY which works on the export, but not in this preview.
Edit:
I just realised that it depends on having multiple instances of a Filter Transformation and their order in the Custom Paramteers.

28

If there is something wrong, could you please send me a sample file?