Support Vertical Mixed Text

[JimBobSquarePants]

Prerequisites

• [x] I have written a descriptive pull-request title
• [x] I have verified that there are no overlapping pull-requests open
• [x] I have verified that I am following matches the existing coding patterns and practice as demonstrated in the repository. These follow strict Stylecop rules :cop:.
• [x] I have provided test coverage for my change (where applicable)

Description

Updates the glyph renderers to handle support for Unicode Standard Annex #50 Unicode Vertical Text Layout

Note: I've discovered an issue when rendering the decorations over certain CFF fonts in that holes are left, however I'm unable to determine what the cause could be. The paths themselves look ok.

This only affects filling a glyph collection.

[codecov[bot]]

Codecov Report

Merging #271 (dbb1ef6) into main (f72bd7a) will increase coverage by 0%. The diff coverage is 90%.

@@         Coverage Diff         @@
##           main   #271   +/-   ##
===================================
  Coverage    78%    79%           
===================================
  Files        97     97           
  Lines      5065   5088   +23     
  Branches    932    945   +13     
===================================
+ Hits       3983   4025   +42     
+ Misses      898    875   -23     
- Partials    184    188    +4     

Flag	Coverage Δ
unittests	79% <90%> (+<1%)	:arrow_up:

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Impacted Files	Coverage Δ
...ImageSharp.Drawing/Shapes/Text/BaseGlyphBuilder.cs	88% <77%> (+31%)	:arrow_up:
...rocessing/Processors/Text/RichTextGlyphRenderer.cs	95% <100%> (+<1%)	:arrow_up:

... and 1 file with indirect coverage changes

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[JimBobSquarePants]

@tocsoft I couldn't help myself and implemented the smart pixel clamping I was on about in a manner that allowed preserving defined pen thickness. The results look great 😁