/// 

/// 隨機(jī)驗(yàn)證碼
/// 
public class RandomCaptcha : DefaultCaptcha
{
    private static readonly Random random = new();
    private static readonly CaptchaType[] captchaTypes = Enum.GetValues();
    public RandomCaptcha(IOptionsSnapshot options, IStorage storage) : base(options, storage)
    {
    }
    /// 

    /// 更新選項(xiàng)
    /// 
    /// 
    protected override void ChangeOptions(CaptchaOptions options)
        // 隨機(jī)驗(yàn)證碼類型
        options.CaptchaType = captchaTypes[random.Next(0, captchaTypes.Length)];
        // 當(dāng)是算數(shù)運(yùn)算時(shí)，CodeLength是指運(yùn)算數(shù)個(gè)數(shù)
        if (options.CaptchaType.IsArithmetic())
        {
            options.CodeLength = 2;
        }
        else
            options.CodeLength = 4;
        // 如果包含中文時(shí)，使用kaiti字體，否則文字亂碼
        if (options.CaptchaType.ContainsChinese())
            options.ImageOption.FontFamily = DefaultFontFamilys.Instance.Kaiti;
            options.ImageOption.FontSize = 24;
            options.ImageOption.FontFamily = DefaultFontFamilys.Instance.Actionj;
        // 動(dòng)靜隨機(jī)
        options.ImageOption.Animation = random.Next(2) == 0;
        // 干擾線隨機(jī)
        options.ImageOption.InterferenceLineCount = random.Next(1, 4);
        // 氣泡隨機(jī)
        options.ImageOption.BubbleCount = random.Next(1, 4);
        // 其他選項(xiàng)...
}

// 內(nèi)存存儲(chǔ)， 基于appsettings.json配置
builder.Services.AddCaptcha(builder.Configuration);
// 開啟隨機(jī)驗(yàn)證碼
builder.Services.Add(ServiceDescriptor.Scoped());

public class ResourceFontFamilysFinder
{
    private static Lazy> _fontFamilies = new Lazy>(() =>
    {
        var fontFamilies = new List();
        var assembly = Assembly.GetExecutingAssembly();
        var names = assembly.GetManifestResourceNames();
        if (names?.Length > 0 == true)
        {
            var fontCollection = new FontCollection();
            foreach (var name in names)
            {
                if (!name.EndsWith("ttf")) continue;
                fontFamilies.Add(fontCollection.Add(assembly.GetManifestResourceStream(name)));
            }
        }
        return fontFamilies;
    });
    public static FontFamily Find(string name)
        return _fontFamilies.Value.First(e => e.Name == name);
    }
}

// 內(nèi)存存儲(chǔ)， 基于appsettings.json配置
builder.Services.AddCaptcha(builder.Configuration, options =>
{
    // 自定義字體
    options.ImageOption.FontSize = 28;
    options.ImageOption.FontFamily = ResourceFontFamilysFinder.Find("KG HAPPY"); // 字體的名字在打開ttf文件時(shí)會(huì)顯示
});