Max Size of a Glyph

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ClintGoss
Posts: 51
Joined: Mon Nov 06, 2017 2:18 pm

Max Size of a Glyph

Post by ClintGoss » Mon Apr 15, 2019 11:41 am

It looks like FC limits the size of a glyph to the (symmetrical) range -16,383 to +16,383 (from zooming out and in on a design window). Is there a reason for this that I am missing?

The OPSpec 1.8.3 declares these points as int16 (I'm looking at the glyph table, Simple Glyph Description, xCoordinates[] array). This would seem to imply an (asymmetrical) range of -32,768 to +32,767.

DelmarGin
Posts: 1
Joined: Wed Apr 17, 2019 8:53 am

Re: Max Size of a Glyph

Post by DelmarGin » Thu Apr 18, 2019 11:30 am

Wouldn't an asymmetrical range throw everything out of balance? I guess not.

ClintGoss
Posts: 51
Joined: Mon Nov 06, 2017 2:18 pm

Re: Max Size of a Glyph

Post by ClintGoss » Thu Apr 18, 2019 6:21 pm

I think the "asymmetrical" comes from two's complement math, which generally can represent one more negative number than positive number for a given number of bits.

My core question is:

For an [X,Y] point in a glyph, what is the allowed range for X and Y?

I'm really just trying to find the answer to this question. I'm wondering if FC is limiting the range to -16,383 to +16,383 because the OpenType spec limits the range, or for some other reason.

The int16 data type would seem to imply a range of -32,768 to +32,767 ...

-Clint

ClintGoss
Posts: 51
Joined: Mon Nov 06, 2017 2:18 pm

Re: Max Size of a Glyph

Post by ClintGoss » Sun Apr 21, 2019 3:17 pm

Looks like there are bona fide Arabic fonts with coordinates well past the 16K bounds, and FCP seems to handle them fairly well (although there is no working grid beyond 16K, and you can't zoom in to do detailed work, but the fonts are exported OK). However, there are other issues in this area ...

See the post in the FontCreator - Bug Reports forum with the title Glyph Coordinate Bounds.

-Clint

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