Graphite fonts don't show up

[classilla]

It always falls back on harfbuzz rendering. We should also verify the collision fixing at the bottom of the page if we get Fx45 up.

http://scripts.sil.org/cms/scripts/page.php?site_id=projects&item_id=graphite_fontdemo

[classilla]

It does not work on 45 with or without graphite enabled either. Not a launch blocker but we should fix the underlying security issue and then see what's gone wrong.

[classilla]

If we do this, we should just update to whatever's in 52 first. There are many upstream changes.

[classilla]

The security aspects of Graphite are now becoming a concern. See https://bugzilla.mozilla.org/show_bug.cgi?id=1331915 . Unless there's an easy upstream update, this might become wontfix.

[classilla]

Even with all the updates, they still don't appear. OTS does not filter the font and calls them valid. With debugging in Graphite2 itself, we get this:

Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2
Face::Table::Table 53696c66
Face::Table::Table 68656164
::CheckTable failed
Face::Table::Table 68686561
Face::Table::Table 686d7478
Face::Table::Table 676c7966
Face::Table::Table 6c6f6361
loading
!head
!head
error#2

[classilla]

Commenting out the call to CheckTable enables the font to load!

[classilla]

It's not correctly validating the head table.

[classilla]

It looks like a padding problem. The size of the loaded table is two bytes shorter than Sfnt::FontHeader. All the other fields check out.

Face::Table::Table 53696c66
Face::Table::Table 68656164
CheckTable::head 1 54 56
CheckTable::head 2 1
CheckTable::head 2 1
CheckTable::head 2 1
CheckTable::head 2 1
CheckTable::head 2 0
::CheckTable failed

[classilla]

(iow, the struct is two bytes longer than what is actually in the table)

[classilla]

Since the glyph data format field also matches, the extra two bytes must be at the end. This is probably an artifact of alignment, so I'm going to change the table function that allocates sizes to round up to the nearest 32-bit word.

[classilla]

Tested working on the Graphite Demo page.