生成验证码图片

生成验证码图片

引用 SixLabors.Fonts

引用 SixLabors.ImageSharp

引用 SixLabors.ImageSharp.Drawing

private static readonly string RandomString = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWSYZ";

/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="verifyCode"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
public static byte[] GenerateImgVerifyCode(string verifyCode, int width = 128, int height = 45)
{
    ////根据验证码的长度确定输出图片的宽度
    //int iWidth = (int)Math.Ceiling(verifyCode.Code.Length * 15m);

    using Image image = new Image<Rgba32>(width, height);
    //漆底色白色
    image.Mutate(x => x.DrawLine(Pens.DashDot(Color.White, width), new PointF[] { new PointF() { X = 0, Y = 0 }, new PointF() { X = width, Y = height } }));

    FontCollection collection = new();
    //加载字体
    FontFamily family = collection.Add("./wwwroot/fonts/JetBrainsMono-Bold.ttf");
    Font font = family.CreateFont(20, FontStyle.Bold);

    PointF startPointF = new PointF(5, 5);
    Random random = new Random(); //随机数产生器

    Color[] colors = [Color.Red, Color.Blue, Color.Green, Color.Purple, Color.Peru, Color.LightSeaGreen, Color.Lime, Color.Magenta, Color.Maroon, Color.MediumBlue, Color.MidnightBlue, Color.Navy];
    //绘制验证码
    for (int i = 0; i < verifyCode.Length; i++)
    {
        image.Mutate(x => x.DrawText(verifyCode[i].ToString(), font, colors[random.Next(colors.Length)], startPointF));
        startPointF.X += (int)(width - 10) / verifyCode.Length;
        startPointF.Y = random.Next(5, 10);
    }

    var pen = Pens.DashDot(Color.Silver, 1);

    //绘制银色背景噪音线30条
    for (var k = 0; k < 30; k++)
    {
        PointF[] points =
        [
            new PointF(random.Next(width), random.Next(height)),
            new PointF(random.Next(width), random.Next(height)),
        ];
        image.Mutate(x => x.DrawLine(pen, points));
    }
    using MemoryStream stream = new MemoryStream();
    image.SaveAsGif(stream);
    return stream.ToArray();

}

/// <summary>
/// 获取Code码
/// </summary>
/// <returns></returns>
public static string GetRandomString()
{
    Random random = new();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < 4; i++)
    {
        int number = random.Next(RandomString.Length);
        sb.Append(RandomString[number]);
    }
    return sb.ToString();
}