meeting-assistant/MeetingAssistant/Taskbar/TaskbarIconRenderer.cs

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;
using System.Runtime.InteropServices;
using System.Runtime.Versioning;
using MeetingAssistant.Recording;

namespace MeetingAssistant.Taskbar;

[SupportedOSPlatform("windows")]
internal static class TaskbarIconRenderer
{
    private const int IconSize = 16;
    private const float GlyphPixelGridOffsetX = -0.5f;

    public static Icon CreateIcon(RecordingProcessState state)
    {
        using var bitmap = RenderBitmap(state);
        var handle = bitmap.GetHicon();
        try
        {
            return (Icon)Icon.FromHandle(handle).Clone();
        }
        finally
        {
            DestroyIcon(handle);
        }
    }

    internal static Bitmap RenderBitmap(RecordingProcessState state)
    {
        var (color, text) = state switch
        {
            RecordingProcessState.Recording => (Color.FromArgb(220, 38, 38), "R"),
            RecordingProcessState.Summarizing => (Color.FromArgb(37, 99, 235), "S"),
            _ => (Color.FromArgb(75, 85, 99), "I")
        };

        var bitmap = new Bitmap(IconSize, IconSize, PixelFormat.Format32bppArgb);
        using var graphics = Graphics.FromImage(bitmap);
        graphics.Clear(Color.Transparent);
        graphics.SmoothingMode = SmoothingMode.AntiAlias;
        graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
        using var brush = new SolidBrush(color);
        graphics.FillEllipse(brush, 1, 1, 14, 14);
        DrawCenteredGlyph(graphics, text);
        return bitmap;
    }

    private static void DrawCenteredGlyph(Graphics graphics, string text)
    {
        using var path = new GraphicsPath();
        using var format = StringFormat.GenericTypographic;
        using var fontFamily = CreateGlyphFontFamily(out var fontStyle);
        path.AddString(
            text,
            fontFamily,
            (int)fontStyle,
            9,
            Point.Empty,
            format);
        var bounds = path.GetBounds();
        using var transform = new Matrix();
        transform.Translate(
            (IconSize - bounds.Width) / 2 - bounds.Left + GlyphPixelGridOffsetX,
            (IconSize - bounds.Height) / 2 - bounds.Top);
        path.Transform(transform);
        using var textBrush = new SolidBrush(Color.White);
        graphics.FillPath(textBrush, path);
    }

    private static FontFamily CreateGlyphFontFamily(out FontStyle fontStyle)
    {
        foreach (var name in new[] { "Segoe UI", "Arial", "DejaVu Sans", "Liberation Sans", "Noto Sans" })
        {
            try
            {
                var family = new FontFamily(name);
                if (TryGetUsableStyle(family, out fontStyle))
                {
                    return family;
                }

                family.Dispose();
            }
            catch (ArgumentException)
            {
            }
        }

        using var installedFonts = new InstalledFontCollection();
        foreach (var installedFamily in installedFonts.Families)
        {
            try
            {
                var family = new FontFamily(installedFamily.Name);
                if (TryGetUsableStyle(family, out fontStyle))
                {
                    return family;
                }

                family.Dispose();
            }
            catch (ArgumentException)
            {
            }
        }

        fontStyle = FontStyle.Bold;
        return FontFamily.GenericSansSerif;
    }

    private static bool TryGetUsableStyle(FontFamily family, out FontStyle fontStyle)
    {
        if (family.IsStyleAvailable(FontStyle.Bold))
        {
            fontStyle = FontStyle.Bold;
            return true;
        }

        if (family.IsStyleAvailable(FontStyle.Regular))
        {
            fontStyle = FontStyle.Regular;
            return true;
        }

        fontStyle = FontStyle.Regular;
        return false;
    }

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool DestroyIcon(IntPtr hIcon);
}