Pilz/Pilz.UI/Symbols/SymbolFactory.cs

using System.Reflection;

namespace Pilz.UI.Symbols;

public abstract class SymbolFactory<TSymbols> : ISymbolFactory<TSymbols>
{
    public abstract string GetImageRessourcePath(TSymbols svgImage);
    public abstract Assembly GetImageResourceAssembly();

    protected virtual Size ResolveCommonSize(SymbolSize size)
    {
        return size switch
        {
            SymbolSize.Small => new Size(16, 16),
            SymbolSize.Medium => new Size(20, 20),
            SymbolSize.Large => new Size(32, 32),
            _ => Size.Empty,
        };
    }

    public virtual Stream? GetImageRessourceStream(TSymbols svgImage)
    {
        var asm = GetImageResourceAssembly();
        var path = GetImageRessourcePath(svgImage);
        return asm.GetManifestResourceStream(path);
    }

    public virtual Image? GetImage(TSymbols svgImage, SymbolSize size)
    {
        return GetImage(svgImage, ResolveCommonSize(size));
    }

    public virtual Image? GetImage(TSymbols svgImage, Size size)
    {
        using var stream = GetImageRessourceStream(svgImage);

        if (stream is null)
            return null;

        var img = Image.FromStream(stream);

        if (!size.IsEmpty)
        {
            var img2 = new Bitmap(size.Width, size.Height);
            using var g = Graphics.FromImage(img2);
            g.DrawImage(img2, 0, 0, size.Width, size.Height);
            img.Dispose();
            img = img2;
        }

        return img;
    }
}