Equivalent of WPF GlyphTypeface (loaded from URI)

[gebodal]

Hello all,

I am trying the classic, to port a WPF application to Avalonia. In this project, there is a need to draw and position individual font glyphs (by glyph index in the font file, rather than unicode codepoint), and I was doing this via the WPF GlyphTypeface class, using something like the following:

ushort glyphIndex = 10;
double fontSize = 12;

Uri fontUri = new Uri("file://path/to/my/font.ttf"); // In WPF, this also supports TrueType/OpenType font collections, using "#1" at the end, or similar

GlyphTypeface glyphs = new GlyphTypeface(fontUri);

Geometry geometry = glyphs .GetGlyphOutline(glyphIndex, fontsize, fontsize);

// This then gets added into a `GeometryDrawing` or similar to be displayed on a canvas

The fonts have to be loaded in dynamically, and cannot be made part of the application. And it needs to support font collection files (.ttc, .otc).

I found a reference to a GlyphTypeface class in Avalonia using Google, here, but it doesn't seem to be in my installed version of Avalonia (11.0.10) - but there is an IGlyphTypeface?

Similar questions have been asked before, but I don't particularly understand the answers (or there was no satisfying answer), or what level of implementation has come after. There are some code snippets here, but I'm unsure where they're supposed to be inserted? (Into my own code, or should I be downloading and modifying Avalonia?)

Does anyone have any idea if this can be done in Avalonia currently? And if so, would you be able to share a code snippet or two?

Many thanks in advance for any help you can provide.

[LaurentInSeattle]

After looking at the docs, I would try the following:

Create a Typeface from Family, Weight, Style
Create a GlyphTypeface from Typeface
Get the Glyphs from the GlyphTypeface
Create a GlyphRun from your selected glyphs
Create a GlyphRunDrawing object from the GlyphRun
Use it in a DrawingGroup or draw it directly if you have a DrawingContext

HTH
Warning => Years of XP with WPF, but still a noob with Avalonia. I might be wrong...

[gebodal]

Hi, thanks for the response!

Do you have any idea how one creates a Typeface/FontFamily from a non-resource font file?

[Gillibald]

We can add https://learn.microsoft.com/en-us/dotnet/api/system.windows.media.glyphtypeface.getglyphoutline?view=windowsdesktop-8.0

We currently only support creating a geometry from FormattedText.

Loading typeface from file is currently only possible via some custom code. Direct support can be added.

[gebodal]

Hi, thanks for getting back on this!

One of the iterations of my current project used FormattedText for this part, so I can work with that, I think.

This custom code you mention, do you happen to have a code snippet? Would it be something I need to do inside the Avalonia source code? (Which I can do, but I'd rather not have to!)

[Gillibald]

#13563 (comment)

[gebodal]

Ah, yes, I saw that one, but it just says "Can modify", and I can't work out which parts of the code are being modified. Are EmbeddedFontCollection and FontManager existing classes that need altering or extending, or am I creating new classes within my project...? I got a bit lost here.