.Net Core Graphic Verification Code

This article introduces the use of third-party ZKWeb.System.Drawing to implement the verification code function under .Net Core.

通过测试的系统： Windows 8.1 64bit Ubuntu Server 16.04 LTS 64bit Fedora 24 64bit CentOS 7.2 64bit 可以实现以下功能: Open jpg, bmp, ico, png Save jpg, bmp, ico, png Resize image Draw graphics with brush and pen Open font and draw string

The above is the official information.

No.1 project introduces ZKWeb.System.Drawing

NuGet import package, which Baidu does not know how to do.

No.2 Simple verification code generation

int codeW = 80; int codeH = 30; int fontSize = 16; Random rnd = new Random(); //颜色列表，用于验证码、噪线、噪点 Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue }; //字体列表，用于验证码 string[] font = { "Times New Roman" }; //验证码的字符集，去掉了一些容易混淆的字符 //写入Session、验证码加密 //WebHelper.WriteSession("session_verifycode", Md5Helper.MD5(chkCode.ToLower(), 16)); //创建画布 Bitmap bmp = new Bitmap(codeW, codeH); Graphics g = Graphics.FromImage(bmp); g.Clear(Color.White); //画噪线 for (int i = 0; i < 1; i++) { int x1 = rnd.Next(codeW); int y1 = rnd.Next(codeH); int x2 = rnd.Next(codeW); int y2 = rnd.Next(codeH); Color clr = color[rnd.Next(color.Length)]; g.DrawLine(new Pen(clr), x1, y1, x2, y2); } //画验证码字符串 for (int i = 0; i < chkCode.Length; i++) { string fnt = font[rnd.Next(font.Length)]; Font ft = new Font(fnt, fontSize); Color clr = color[rnd.Next(color.Length)]; g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18, (float)0); } //将验证码图片写入内存流，并将其以 "image/Png" 格式输出 MemoryStream ms = new MemoryStream(); try { bmp.Save(ms, ImageFormat.Png); return ms.ToArray(); } catch (Exception) { return null; } finally { g.Dispose(); bmp.Dispose(); }

No.3 Release deployment and operation

Just go to the picture above, if you don’t know it, look here www.cnblogs.com/niao/p/6057860.html

Note: There is no pressure to generate the verification code under Windows. I use Ubuntu 14 and need to install the gdi package. There will be a prompt in the running log.

Installation method:

Ubuntu 16.04:

apt-get install libgdiplus cd /usr/libln -s libgdiplus.so gdiplus.dll

Fedora 23:

dnf install libgdiplus cd /usr/lib64/ln -s libgdiplus.so.0 gdiplus.dll

CentOS 7:

yum install autoconf automake libtool yum install freetype-devel fontconfig libXft-devel yum install libjpeg-turbo-devel libpng-devel giflib-devel libtiff-devel libexif-devel yum install glib2-devel cairo-devel git clone https://github.com/mono/libgdiplus cd libgdiplus ./autogen.sh make make install cd /usr/lib64/ ln -s /usr/local/lib/libgdiplus.so gdiplus.dll

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