For https://github.com/mono/SkiaSharp/issues/1253

Example.csproj

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>netcoreapp3.1</TargetFramework>
    </PropertyGroup>

    <ItemGroup>
      <PackageReference Include="HarfBuzzSharp" Version="2.6.1.4" />
      <PackageReference Include="SkiaSharp" Version="2.80.0-alpha.13" />
    </ItemGroup>

</Project>

Program.cs

using System;
using System.IO;
using System.Runtime.InteropServices;
using HarfBuzzSharp;
using SkiaSharp;

namespace SkiaCanvas
{
    public static class Program
    {
        static Program()
        {
            var libSkiaSharpPath = Path.GetDirectoryName(typeof(Program).Assembly.Location);
            string runtime;
            switch (Environment.OSVersion.Platform)
            {
                case PlatformID.MacOSX:
                    libSkiaSharpPath = Path.Combine(libSkiaSharpPath, "runtimes", "osx", "native",
                        "libSkiaSharp.dylib");
                    break;
                case PlatformID.Unix:
                    runtime = IntPtr.Size == 4 ? "tizen-x86" : "tizen-x64";
                    libSkiaSharpPath = Path.Combine(libSkiaSharpPath, "runtimes", runtime, "native",
                        "libSkiaSharp.so");
                    break;
                default:
                    runtime = IntPtr.Size == 4 ? "win-x86" : "win-x64";
                    libSkiaSharpPath = Path.Combine(libSkiaSharpPath, "runtimes", runtime, "native",
                        "libSkiaSharp.dll");
                    break;
            }

            Console.WriteLine($"Loading native lib from '{libSkiaSharpPath}'");
            var lib = NativeLibrary.Load(libSkiaSharpPath);
            Console.WriteLine(lib == IntPtr.Zero
                ? $"Loading native lib from '{libSkiaSharpPath}' failed"
                : $"Loading native lib from '{libSkiaSharpPath}' successful"
            );
        }

        public static void Main()
        {
            const float size = 12f;
            const float height = size * 2;
            const float width = 1300f;
            const float x = 10;

            using var colorSpace = SKColorSpace.CreateSrgb();
            using var surface = SKSurface.Create(new SKImageInfo((int)width,
                    (int)height,
                    SKColorType.Bgra8888,
                    SKAlphaType.Premul,
                    colorSpace),
                new SKSurfaceProperties(SKSurfacePropsFlags.None, SKPixelGeometry.Unknown)
            );

            var paint = new SKPaint
            {
                IsAntialias = true,
                IsDither = false,
                Style = SKPaintStyle.Fill,
                Color = new SKColor(0, 0, 0, 255),
                StrokeMiter = 4,
                StrokeWidth = 0,
                StrokeCap = SKStrokeCap.Butt,
                BlendMode = SKBlendMode.SrcOver
            };

            using var typeFace = SKTypeface.FromFamilyName("Arial",
                SKFontStyleWeight.Bold,
                SKFontStyleWidth.Normal,
                SKFontStyleSlant.Upright
            );

            var msg = "rendered by myLibrary (https://myLibrary.domain)";
            DrawText(surface.Canvas, msg, x, 20.799999f, paint, typeFace, 12);

            using var image = SKBitmap.FromImage(surface.Snapshot());
            using var fileStream = new SKFileWStream("output.png");
            image.Encode(fileStream, SKEncodedImageFormat.Png, 100);
        }

        private static void DrawText(SKCanvas surfaceCanvas, string msg, in float x, float y, SKPaint paint, SKTypeface typeface, int size)
        {
            using var font = MakeHarfBuzzFont(typeface, size);
            using var buffer = new HarfBuzzSharp.Buffer
            {
                Direction = Direction.LeftToRight,
                Language = Language.Default
            };
            buffer.AddUtf8(msg);

            font.Shape(buffer);

            var infos = buffer.GlyphInfos;
            var positions = buffer.GlyphPositions;

            using var skFont = new SKFont
            {
                Edging = SKFontEdging.Antialias,
                Subpixel = true,
                Hinting = SKFontHinting.Normal,
                Typeface = typeface,
                Size = size
            };
            
            using var blobBuilder = new SKTextBlobBuilder();
            var runBuffer = blobBuilder.AllocatePositionedRun(skFont, infos.Length);

            var bufferGlyphs = runBuffer.GetGlyphSpan();
            var bufferPositions = runBuffer.GetPositionSpan();

            var width = 0.0f;
            for (var i = 0; i < infos.Length; i++)
            {
                bufferGlyphs[i] = (ushort)infos[i].Codepoint;

                var xOffset = width + HarfBuzzToSkiaFontSize * positions[i].XOffset;
                var yOffset = HarfBuzzToSkiaFontSize * -positions[i].YOffset;
                bufferPositions[i] = new SKPoint(xOffset, yOffset);

                width += HarfBuzzToSkiaFontSize * positions[i].XAdvance;
            }

            var blob = blobBuilder.Build();
            surfaceCanvas.DrawText(blob, x, y, paint);
        }

        private const int SkiaToHarfBuzzFontSize = 1 << 16;
        private const float HarfBuzzToSkiaFontSize = 1f / SkiaToHarfBuzzFontSize;
        private static Font MakeHarfBuzzFont(SKTypeface typeface, int size)
        {
            using var stream = typeface.OpenStream(out var ttcIndex);
            var data = Marshal.AllocCoTaskMem(stream.Length);
            stream.Read(data, stream.Length);
            using var blob = new Blob(data, stream.Length, MemoryMode.ReadOnly, () => { Marshal.FreeCoTaskMem(data); });
            blob.MakeImmutable();

            using var face = new Face(blob, ttcIndex)
            {
                Index = ttcIndex,
                UnitsPerEm = typeface.UnitsPerEm
            };

            var font = new Font(face);
            var scale = size * SkiaToHarfBuzzFontSize;
            font.SetScale(scale, scale);
            font.SetFunctionsOpenType();

            return font;
        }
    }
}