Fallback in readCmapTable, instead of using error, for TrueType fonts with unsupported cmap formats (bug 1200096)
#6407
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…onts with unsupported cmap formats (bug 1200096) Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1200096. The problematic font has a `format 2` cmap, which we've never supported properly. Prior to PR 2606, we were able to fallback to a working state, despite not having proper support for that cmap format. Obviously the best/correct solution would be to implement actual support for more cmap formats[1]. However, I'm hoping that a simple patch will be OK for now, given that: - `format 2` cmaps seem to be quite rare in practice, since this has been broken for 2.5 years before anyone noticed. - Having a simple patch will make potential uplifts a lot easier. [1] See the specification at https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6cmap.html
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/botio-windows preview |
From: Bot.io (Windows)ReceivedCommand cmd_preview from @Snuffleupagus received. Current queue size: 0 Live output at: http://107.22.172.223:8877/da980fd669b0de4/output.txt |
From: Bot.io (Windows)SuccessFull output at http://107.22.172.223:8877/da980fd669b0de4/output.txt Total script time: 1.05 mins Published |
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/botio test |
From: Bot.io (Windows)ReceivedCommand cmd_test from @Snuffleupagus received. Current queue size: 0 Live output at: http://107.22.172.223:8877/0e9356aae7154f6/output.txt |
From: Bot.io (Linux)ReceivedCommand cmd_test from @Snuffleupagus received. Current queue size: 0 Live output at: http://107.21.233.14:8877/bcf7817cde27a8b/output.txt |
From: Bot.io (Windows)SuccessFull output at http://107.22.172.223:8877/0e9356aae7154f6/output.txt Total script time: 18.93 mins
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From: Bot.io (Linux)SuccessFull output at http://107.21.233.14:8877/bcf7817cde27a8b/output.txt Total script time: 19.43 mins
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/botio makeref |
From: Bot.io (Linux)ReceivedCommand cmd_makeref from @brendandahl received. Current queue size: 0 Live output at: http://107.21.233.14:8877/518e7f522d32cc3/output.txt |
From: Bot.io (Windows)ReceivedCommand cmd_makeref from @brendandahl received. Current queue size: 0 Live output at: http://107.22.172.223:8877/900615deb51ab6c/output.txt |
From: Bot.io (Linux)SuccessFull output at http://107.21.233.14:8877/518e7f522d32cc3/output.txt Total script time: 18.93 mins
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From: Bot.io (Windows)SuccessFull output at http://107.22.172.223:8877/900615deb51ab6c/output.txt Total script time: 18.94 mins
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Fallback in `readCmapTable`, instead of using `error`, for TrueType fonts with unsupported cmap formats (bug 1200096)
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1200096.
The problematic font has a
format 2cmap, which we've never supported properly. Prior to PR #2606, we were able to fallback to a working state, despite not having proper support for that cmap format.Obviously the best/correct solution would be to implement actual support for more cmap formats[1]. However, I'm hoping that a simple patch will be OK for now, given that:
format 2cmaps seem to be quite rare in practice, since this has been broken for 2.5 years before anyone noticed.[1] See the specification at https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6cmap.html