Update to a much later version of skia (m80)

[mattleibow]

Description of Change

Update to the latest (m80 at this time) version of skia.

This has been published that to the internal feed as 2.80.0-pr.986.37

Tasks

• Merge native skia
• Get native skia building
  • Hacking out the problems so it compiles
  • Fixing the problems properly
  • Bind any new members that are essential
• Update the managed bindings
  • Hacking out the problems so it compiles
  • Fixing/adding unit tests
  • Fixing the problems properly
  • Bind any new members that are essential
• Update all source libraries (this shouldn't be too much work as these APIs are the same)
  • SkiaSharp.Views (there are a LOT of platforms)
  • SkiaSharp.Views.Forms
• Update all samples (there are even more samples)
  • Update basic samples
  • Update feature samples

Bugs Fixed

• Possibly a few...
• Fixes Migrate to SKFont #711

API & Behavioral Changes

Changes so far (excluding the changes listed in mono/skia#64):

• New minimum versions
  • Android API 16 (Jelly Bean)
  • Ubuntu 16.04 with later Clang versions (only for the default builds, but you can always build some ancient Linux if you build your own Clang)
  • UWP 10.0.16299 (Fall Creators Update)
• Using Docker images on CI to build Linux
  • You can still build on Linux without Docker (you just need to manually install the tools)
• HarfBuzz updated to v2.6.2
• Targeting the newer tools
  • mono 6.4.0
  • Xcode 11
  • .NET Core 3.0
  • VS 2019
• TODO

[Gillibald]

In my opinion SKFont should only measure and break spans of glyphs. Supplying a string to these methods leads to errors. This only works for text that doesn't need extra shaping when you supply a string.

[mattleibow]

@Gillibald I agree. I just have to add it back for backwards compat 😢

However... I can just keep SKFont to be glyph-only...

Doesn't the MeasureText fall into the same category as GetGlyphWidths and CountGlyphs? They also take strings.

Finally, even though you and I know that we need to get glyphs, many people just want to use simple .NET strings as text...

[Gillibald]

Y all these methods should follow this logic. I consider SKFont a low level component. SKPaint can expose overloads that take a string. SKFont doesn't need that and should do better. Maybe we should document it somehow that this only works for basic scenarios and link to the SkShaper component.

Edit: This also doesn't handle surrogate pairs if I am not mistaken but that might be wrong.

[mattleibow]

@Gillibald

This also doesn't handle surrogate pairs

I think it does, which is actually quite nice (or maybe I am mistaken): https://github.com/google/skia/blob/chrome/m80/src/utils/SkUTF.cpp#L70-L94

And I think I agree with that logic of keeping SKFont low-level and SKPaint as the "more general" usage.