FontLab 5.2.1 Output: GSUB feature 'ÿÿÿÿ' causes overflow of offset to a subtable

manuelcorradine16 April 2014 · 12:41

Hi all,

I'm designing a handwriten font wich contain many alternate sets of characters and I programmed a calt feature to randomize it. The feature contains a lot of lines mixing and conditioning the substition of each character. I thing the sintaxis is fine and the replacement works fine too, but when I increase the number of characters in each of the classes used in the code the output panel shows the following warning:

[FATAL] GSUB feature 'ÿÿÿÿ' causes overflow of offset to a subtable (0x1140a)

(I don't know why the name of the feature is swhown without the correct name).
I guess it means the code becomes too heavy but searching and reading a lot of posts of similar bugs I concluded that the responsible of this issue was the program. So I decided to try compiling the font in an older version (FL 5.0) and there aren't any problem and the compiled font works fine.
Please tell me what can I do to improve my version of FL to avoid this issue. Any comment will be appreciated.

Johnych17 April 2014 · 04:59

I think you can fix this by defining several lookup tables in the calt feature and specifying the useExtension keyword in each of the lookups.
Something like this:

feature calt { # Alternates lookup calt_1 useExtension { ... } calt_1; lookup calt_2 useExtension { ... } calt_2; lookup calt_3 useExtension { ... } calt_3; } calt;

Johnych

manuelcorradine22 April 2014 · 05:54

Thank you johnych for your suggestion but I also tried it and doesn't work.