[HarfBuzz] finer-grained clustering options break behavior :(

[Behdad Esfahbod]

On 15-08-02 01:32 PM, Jonathan Kew wrote:
> Hey Behdad,
> 
> In https://bugzilla.mozilla.org/show_bug.cgi?id=729993, we'd like to switch
> Gecko to use  HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS, so as to enable
> independent mark coloring. However, it turns out this breaks other aspects of
> rendering behavior; in particular, we get test failures in a couple of tests
> using variation selectors.
> 
> Looking at the code, I believe this is because _hb_ot_shape_normalize relies
> on the .cluster field to identify the ranges within which it operates. We'll
> need to fix this to use unicode properties instead, or something like that.
> 
> Similarly, we get a failure in a test for fallback mark positioning, because
> _hb_ot_shape_fallback_position also relies on .cluster.
> 
> For these operations, we need to work on a consistent "cluster" regardless of
> the setting of the HB_BUFFER_CLUSTER_LEVEL option.

I just pushed your patches out, so this should be in good shape now.

Thanks!
-- 
behdad
http://behdad.org/