SecMPS/api_sqlsugar/VolPro.Core/Utilities/VierificationCodeServices.cs

using SkiaSharp;
using System;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;

namespace VolPro.Core.Utilities
{
    public static class VierificationCodeServices
    {
        static VierificationCodeServices()
        {
        }
        private static readonly SKColor[] colors = { SKColors.Black, SKColors.Green, SKColors.Brown };

        /// <summary>
        /// 
        /// </summary>
        /// <param name="code"></param>
        /// <returns></returns>
        public static string CreateBase64Image(string code)
        {
            var random = new Random();
            var info = new SKImageInfo((int)code.Length * 18, 32);
            using var bitmap = new SKBitmap(info);
            using var canvas = new SKCanvas(bitmap);

            canvas.Clear(SKColors.White);

            // 从 fonts 文件夹加载字体文件（相对于运行目录）
            string fontPath = Path.Combine(AppContext.BaseDirectory, "fonts", "DejaVuSans.ttf");
            if (!File.Exists(fontPath))
                throw new FileNotFoundException($"字体文件未找到: {fontPath}");

            using var typeface = SKTypeface.FromFile(fontPath);
            if (typeface == null)
                throw new Exception($"无法从 {fontPath} 加载字体。");

            using var pen = new SKPaint();
            pen.FakeBoldText = true;
            pen.Style = SKPaintStyle.Fill;
            pen.TextSize = 20;
            pen.Typeface = typeface;   // 使用加载的本地字体

            // 绘制随机字符
            for (int i = 0; i < code.Length; i++)
            {
                pen.Color = random.GetRandom(colors); // 假设 colors 是外部定义的静态颜色数组
                var point = new SKPoint
                {
                    X = i * 16,
                    Y = 22
                };
                canvas.DrawText(code.Substring(i, 1), point, pen);
            }

            // 绘制噪点
            var points = Enumerable.Range(0, 100).Select(
                _ => new SKPoint(random.Next(bitmap.Width), random.Next(bitmap.Height))
            ).ToArray();
            canvas.DrawPoints(SKPointMode.Points, points, pen);

            // 绘制贝塞尔线条（原有逻辑存在 p1~p4 全为零的问题，此处保留原样）
            for (int i = 0; i < 2; i++)
            {
                var p1 = new SKPoint(0, 0);
                var p2 = new SKPoint(0, 0);
                var p3 = new SKPoint(0, 0);
                var p4 = new SKPoint(0, 0);
                var touchPoints = new SKPoint[] { p1, p2, p3, p4 };

                using var bPen = new SKPaint();
                bPen.Color = random.GetRandom(colors);
                bPen.Style = SKPaintStyle.Stroke;

                using var path = new SKPath();
                path.MoveTo(touchPoints[0]);
                path.CubicTo(touchPoints[1], touchPoints[2], touchPoints[3]);
                canvas.DrawPath(path, bPen);
            }

            return bitmap.ToBase64String(SKEncodedImageFormat.Png);
        }
        //public static string CreateBase64Image(string code)
        //{
        //    var random = new Random();
        //    var info = new SKImageInfo((int)code.Length * 18, 32);
        //    using var bitmap = new SKBitmap(info);
        //    using var canvas = new SKCanvas(bitmap);

        //    canvas.Clear(SKColors.White);

        //    using var pen = new SKPaint();
        //    pen.FakeBoldText = true;
        //    pen.Style = SKPaintStyle.Fill;
        //    pen.TextSize = 20;// 0.6f * info.Width * pen.TextSize / pen.MeasureText(code);

        //    // 检查 "DejaVu Sans" 字体是否存在
        //    using var testTypeface = SKFontManager.Default.MatchFamily("DejaVu Sans");
        //    if (testTypeface == null || string.IsNullOrEmpty(testTypeface.FamilyName))
        //    {
        //        throw new Exception("系统中未找到 'DejaVu Sans' 字体。");
        //    }

        //    //绘制随机字符
        //    for (int i = 0; i < code.Length; i++)
        //    {
        //        pen.Color = random.GetRandom(colors);//随机颜色索引值

        //        pen.Typeface = SKTypeface.FromFamilyName("DejaVu Sans", 700, 20, SKFontStyleSlant.Italic);//配置字体
        //        var point = new SKPoint()
        //        {
        //            X = i * 16,
        //            Y = 22// info.Height - ((i + 1) % 2 == 0 ? 2 : 4),

        //        };
        //        canvas.DrawText(code.Substring(i, 1), point, pen);//绘制一个验证字符

        //    }

        //    // 绘制噪点
        //    var points = Enumerable.Range(0, 100).Select(
        //        _ => new SKPoint(random.Next(bitmap.Width), random.Next(bitmap.Height))
        //    ).ToArray();
        //    canvas.DrawPoints(
        //        SKPointMode.Points,
        //        points,
        //        pen);

        //    //绘制贝塞尔线条
        //    for (int i = 0; i < 2; i++)
        //    {
        //        var p1 = new SKPoint(0, 0);
        //        var p2 = new SKPoint(0, 0);
        //        var p3 = new SKPoint(0, 0);
        //        var p4 = new SKPoint(0, 0);

        //        var touchPoints = new SKPoint[] { p1, p2, p3, p4 };

        //        using var bPen = new SKPaint();
        //        bPen.Color = random.GetRandom(colors);
        //        bPen.Style = SKPaintStyle.Stroke;

        //        using var path = new SKPath();
        //        path.MoveTo(touchPoints[0]);
        //        path.CubicTo(touchPoints[1], touchPoints[2], touchPoints[3]);
        //        canvas.DrawPath(path, bPen);
        //    }
        //    return bitmap.ToBase64String(SKEncodedImageFormat.Png);
        //}

        public static T GetRandom<T>(this Random random, T[] tArray)
        {
            if (random == null) random = new Random();
            return tArray[random.Next(tArray.Length)];
        }

        /// <summary>
        /// SKBitmap转Base64String
        /// </summary>
        /// <param name="bitmap"></param>
        /// <param name="format"></param>
        /// <returns></returns>
        public static string ToBase64String(this SKBitmap bitmap, SKEncodedImageFormat format)
        {
            using var memStream = new MemoryStream();
            using var wstream = new SKManagedWStream(memStream);
            bitmap.Encode(wstream, format, 32);
            memStream.TryGetBuffer(out ArraySegment<byte> buffer);
            return $"{Convert.ToBase64String(buffer.Array, 0, (int)memStream.Length)}";
        }
    }
}