关于.Net 6.0 在Linux ,Docker容器中，不安装任何依赖就生成图形验证码！

using SkiaSharp;
using System.Drawing;
using System.Drawing.Text;

namespace VertifyCode
{
    public class VerifyCodeHelper
    {
        private static readonly char[] Chars = { '0','1','2','3','4','5','6','8','9',
                                                'A','B','C','D','E','F','G','H','I','J','K', 'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z' };
        //private static readonly int Width = 90;
        //private static readonly int Height = 35;

        private static string GenCode(int num)
        {
            var code = string.Empty;
            var r = new Random();

            for (int i = 0; i < num; i++)
            {
                code += Chars[r.Next(Chars.Length)].ToString();
            }

            return code;
        }
        /// <summary>
        /// 获取图像数字验证码
        /// </summary>
        /// <returns></returns>
        public static (string code, byte[] bytes) GetVerifyCode()
        {
            var code = GenCode(4);
            int width = 128;
            int height = 45;

            Random random = new();

            //创建bitmap位图
            using SKBitmap image = new(width, height, SKColorType.Bgra8888, SKAlphaType.Premul);
            //创建画笔
            using SKCanvas canvas = new(image);
            //填充背景颜色为白色            canvas.DrawColor(SKColors.White);

            //画图片的背景噪音线
            for (int i = 0; i < (width * height * 0.015); i++)
            {
                using SKPaint drawStyle = new();
                drawStyle.Color = new(Convert.ToUInt32(random.Next(Int32.MaxValue)));

                canvas.DrawLine(random.Next(0, width), random.Next(0, height), random.Next(0, width), random.Next(0, height), drawStyle);
            }//将文字写到画布上
            using (SKPaint drawStyle = new())
            {
                drawStyle.Color = SKColors.Red;
                drawStyle.TextSize = height;
                drawStyle.StrokeWidth = 1;

                float emHeight = height - (float)height * (float)0.14;
                float emWidth = ((float)width / code.Length) - ((float)width * (float)0.13);
                canvas.DrawText(code, emWidth, emHeight, drawStyle);
            }