86 lines
3.0 KiB
C#
86 lines
3.0 KiB
C#
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using System.Text;
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using SkiaSharp;
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using static IronPython.Modules._ast;
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namespace WebAPIServer.Extensions
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{
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public class CaptchaHelperSkiaSharp
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{
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private static string GenerateRandomText(int length)
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{
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const string valid = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
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StringBuilder res = new StringBuilder();
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Random rnd = new Random();
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while (0 < length--)
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res.Append(valid[rnd.Next(valid.Length)]);
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return res.ToString();
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}
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/// <summary>
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/// 获取图像数字验证码
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/// </summary>
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/// <param name="text">验证码内容，如4为数字</param>
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/// <returns></returns>
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public static byte[] GetVerifyCode(string text)
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{
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int width = 128;
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int height = 45;
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Random random = new();
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//创建bitmap位图
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using SKBitmap image = new(width, height, SKColorType.Bgra8888, SKAlphaType.Premul);
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//创建画笔
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using SKCanvas canvas = new(image);
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//填充背景颜色为白色
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canvas.DrawColor(SKColors.White);
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//画图片的背景噪音线
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for (int i = 0; i < (width * height * 0.015); i++)
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{
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using SKPaint drawStyle = new();
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drawStyle.Color = new(Convert.ToUInt32(random.Next(Int32.MaxValue)));
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canvas.DrawLine(random.Next(0, width), random.Next(0, height), random.Next(0, width), random.Next(0, height), drawStyle);
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}
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//将文字写到画布上
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using (SKPaint drawStyle = new())
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{
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drawStyle.Color = SKColors.Red;
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drawStyle.TextSize = height;
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drawStyle.StrokeWidth = 1;
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float emHeight = height - (float)height * (float)0.14;
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float emWidth = ((float)width / text.Length) - ((float)width * (float)0.13);
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canvas.DrawText(text, emWidth, emHeight, drawStyle);
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}
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//画图片的前景噪音点
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for (int i = 0; i < (width * height * 0.6); i++)
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{
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image.SetPixel(random.Next(0, width), random.Next(0, height), new SKColor(Convert.ToUInt32(random.Next(Int32.MaxValue))));
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}
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using var img = SKImage.FromBitmap(image);
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using SKData p = img.Encode(SKEncodedImageFormat.Png, 100);
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return p.ToArray();
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}
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public static byte[] GenerateCaptchaImage(int width = 100, int height = 40)
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{
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var random = new Random();
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string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
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string captchaText = "";
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for (int i = 0; i < 4; i++) // 生成6个字符的验证码
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{
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captchaText += chars[random.Next(chars.Length)];
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}
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return GetVerifyCode(captchaText);
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}
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}
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}
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