[skottie] Visual-only text valign
Historically, Skottie started with vertical alignment based on the
typographic bounding box. This was meant to account for empty
leading/trailing lines.
At some point [1], the strategy was changed to also take the visual
bounding box into account (union of typographic and visual bounds).
It turns out this is still suboptimal: aligning based on font metrics
yields poor results in practice, and pretty much everyone expects
visual-only alignment.
This CL is an attempt to fix things:
1) update kVisualTop/kVisualCenter/kVisualBottom to use visual bounds
only (as their name implies)
2) introduce kDeprecatedVisualCenter to preserves the old behavior
for compatibility, and use it for the legacy sk_vj flags
The latter is done to minimize disruption for clients which have
adjusted for the current misalignment: luckily they're mostly using the
old sk_vj flag instead of explicit resize/valign policies, and they can
continue to do so without change, while new clients can opt into the
new/improved valign modes.
The change is guarded by a build flag for g3 staging.
[1] https://skia-review.googlesource.com/c/skia/+/224188
Change-Id: I334c1713ce32635e3649711f072a3dcdf6b12244
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/501016
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
3 files changed