Inconsistent Custom Font Behavior on Different Platforms

[YupCore]

I’m experiencing inconsistent behavior with custom font loading in SkiaSharp when rendering SVG files across different platforms (Windows and Linux). On Linux, custom fonts are registered and loaded successfully by a custom ITypefaceProvider, but the rendered output still uses some default font (DejaVu Sans) instead of the intended custom fonts. On Windows, the same code works as expected, rendering the custom fonts correctly. Something is clearly frong in the process of loading fonts.
I've looked at other issues opened here, researched the soure code and looked on other websites like stackoverflow but nowhere this specific issue was described. That's why I'm creating this issue.

Environment:

• SkiaSharp Version: 3.116.1, Svg.Skia Version: 2.0.0.4
• OS:
  • Linux (tested on Kali Linux 2024.4)
  • Windows (tested on Windows 11)
• Runtime: .NET 9

Steps to Reproduce:

• Use the provided CustomTypefaceProvider to register custom fonts (Intro, Akira Expanded, Delecta) from a directory.
• Load an SVG file specifying these fonts (e.g., font-family: Akira Expanded).
• Render the SVG to PNG using SKSvg with the custom typeface provider.
• Run the application on both Windows and Linux.

Expected Behavior:

The output PNG should use the custom fonts (Akira Expanded, Delecta, etc.) as specified in the SVG and registered by the CustomTypefaceProvider on both platforms.
Actual Behavior:

Windows: Custom fonts are rendered correctly in the output PNG.
Linux: Despite the fonts being registered and loaded (confirmed by logs), the output PNG uses the default font DejaVu Sans. Logs show SkiaSharp attempting to load Akira Super (not registered) and falling back to DejaVu Sans.
Logs (Linux):

Registered: Intro  -> /home/user_name/test/Assets/fonts/Intro-Regular.ttf
Registered: Akira Expanded -> /home/user_name/test/Assets/fonts/AKIRA-EXPANDED-DEMO.OTF
Registered: Delecta -> /home/user_name/test/Assets/fonts/Delecta-Medium.otf
Trying to load: Akira Expanded
Loaded: Akira Expanded
SkiaSharp.SKTypeface
Trying to load: Akira Expanded
Loaded: Akira Expanded
SkiaSharp.SKTypeface
Trying to load: Akira Expanded
Loaded: Akira Expanded
SkiaSharp.SKTypeface
Trying to load: Akira Expanded
Loaded: Akira Expanded
SkiaSharp.SKTypeface
Trying to load: Akira Expanded
Loaded: Akira Expanded
SkiaSharp.SKTypeface
Trying to load: DejaVu Sans
Trying to load: DejaVu Sans
Trying to load: DejaVu Sans
Trying to load: DejaVu Sans
Trying to load: DejaVu Sans
Profile SVG generated as 'profile_output.png'
Registered: Intro  -> /home/user_name/test/Assets/fonts/Intro-Regular.ttf
Registered: Akira Expanded -> /home/user_name/test/Assets/fonts/AKIRA-EXPANDED-DEMO.OTF
Registered: Delecta -> /home/user_name/test/Assets/fonts/Delecta-Medium.otf
Trying to load: MyriadPro-Regular, "Myriad Pro"
Trying to load: Delecta
Loaded: Delecta
SkiaSharp.SKTypeface
Trying to load: Delecta
Loaded: Delecta
SkiaSharp.SKTypeface
Trying to load: DejaVu Sans
Trying to load: Delecta
Loaded: Delecta
SkiaSharp.SKTypeface
Trying to load: Delecta
Loaded: Delecta
SkiaSharp.SKTypeface
Leaderboard SVG generated as 'leaderboard_output.png'
Press any key to exit...

The logs show that Akira Expanded is registered and loaded multiple times successfully (Loaded: Akira Expanded), indicating the CustomTypefaceProvider works.
However, SkiaSharp then requests Akira Super (which isn’t registered) and falls back to DejaVu Sans. This suggests a mismatch between what the SVG requests and what the provider supplies, but only on Linux.

Additional Notes:

Fonts are readable and valid on Linux (permissions checked with chmod +r).
libfontconfig1 is installed and functional (fc-list works).
Hardcoding absolute font paths doesn’t resolve the issue.

Test project:
I will also attach a test visual studio project containig code and used svg files which reproduces the specified issue when running on linux.

TestFamilyNames.zip

[YupCore]

also I've noticed a notable diffence in the typeface loading on windows and linux while testing.

Linux:

Registered: Delecta -> /home/user_nane/linux-x64/Assets/fonts/Delecta Medium.otf
Registered: Intro  -> /home/user_nane/linux-x64/Assets/fonts/Intro-Regular.ttf
Registered: Akira Expanded -> /home/user_nane/linux-x64/Assets/fonts/Akira Expanded.otf
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Returning fallback
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Returning fallback
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Returning fallback
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Returning fallback
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Returning fallback
Requesting typeface DejaVu Sans, with weight: 700, fontstylewidth: 5, fontstyle: Upright
Returning fallback
Requesting typeface DejaVu Sans, with weight: 700, fontstylewidth: 5, fontstyle: Upright
Returning fallback
Requesting typeface DejaVu Sans, with weight: 700, fontstylewidth: 5, fontstyle: Upright
Returning fallback
Requesting typeface DejaVu Sans, with weight: 700, fontstylewidth: 5, fontstyle: Upright
Returning fallback
Requesting typeface DejaVu Sans, with weight: 700, fontstylewidth: 5, fontstyle: Upright
Returning fallback

Windows:

Registered: Akira Super -> D:\source\UltimateModBot\bin\x64\Release\net9.0\Assets\fonts\Akira Expanded.otf
Registered: Delecta -> D:\source\UltimateModBot\bin\x64\Release\net9.0\Assets\fonts\Delecta Medium.otf
Registered: Intro -> D:\source\UltimateModBot\bin\x64\Release\net9.0\Assets\fonts\Intro-Regular.ttf
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super
Requesting typeface Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully acquired: Akira Super, with weight: 800, fontstylewidth: 7, fontstyle: Upright
Succesfully loaded: Akira Super

Same code, same font file, different results, linux seems to load fonts entirely differently.
I'm starting to think it's more of an Skia issue than Svg.Skia.

SVGGenerators.cs.txt

[wieslawsoltes]

I think its issue with SkiaSharp or native deps of the SkiaSharp