Change DemiBold behavior from 11.0.x to 11.1.0

[workgroupengineering]

Considering the following xaml

XAML

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="AFontIssue.MainWindow"
        Title="AFontIssue">
  <TextBlock Text="📐 Projects"
             FontSize="54"
             FontWeight="DemiBold"
             />
</Window>

Avalonia 11.0.12 behavior

Avalonia 11.1.0 behavior

Platform: Window 10 x 64

What is the expected behavior?

I attach a sample project. To simulate the problem, just change the AvaloniaVersion property in AFontIssue.csproj.

AFontIssue.zip

[Gillibald]

So the issue is that a regular glyph is rendered instead of a color glyph?

[workgroupengineering]

Yes

[rabbitism]

same happens to semi avalonia demo.

[Gillibald]

I think this is because of bold emulation. There is no Bold/DemiBold variant and therefore the backend emulates the typeface. This seems to remove color glyphs.

[Gillibald]

Should be fixed by: #16489