1. Watermark
1. Canvas
System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.FileContent);
2. Create a drawing object and tell it which picture to draw on
Graphics g = Graphics.FromImage(img);
3. Drawing content
string s = <a href="http://www.php.cn">www.php.cn</a>;
4 . Drawing font
Font f = new Font("黑体",130);
5. Drawing brush
Brush b = new SolidBrush(Color.Red);
6. Start drawing
g.DrawString(s, f, b, 5, 5);
2. Picture verification code
Bitmap bit = new Bitmap(90, 40);//画布大小 Graphics g = Graphics.FromImage(bit);//创建绘制对象,告诉它往哪张图片上绘制 Random r = new Random(); string s = ""; Color color1 = Color.FromArgb(r.Next(155, 255), r.Next(155, 255), r.Next(155, 255)); g.FillRectangle(new SolidBrush(color1), 0, 0, 90, 40);//画布颜色随机 for (int i = 0; i < 10; i++)//随机画干扰线 { Color color3 = Color.FromArgb(r.Next(170, 255), r.Next(190, 255), r.Next(170, 255)); Pen pp = new Pen(new SolidBrush(color3), r.Next(0, 5)); g.DrawLine(pp, r.Next(0, 90), r.Next(0, 40), r.Next(0, 90), r.Next(0, 40)); } string yan = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";//设置随机的验证码,从里面抽取 int wei = 0; for (int i = 0; i < 4; i++)//取四位验证码,颜色随机 { string m = yan.Substring(r.Next(0, yan.Length), 1); s += m; Color color2 = Color.FromArgb(r.Next(0, 155), r.Next(0, 155), r.Next(0, 155)); int w = r.Next(20, 25); Font f = new Font("黑体", w); SolidBrush b = new SolidBrush(color2); g.DrawString(m, f, b, wei, r.Next(0, 10)); wei += w; } Session["YZM"] = s;//把验证码保存到session中 for (int i = 0; i < 251; i++) { Color color3 = Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255)); Pen pp = new Pen(new SolidBrush(color3), r.Next(0, 5)); int a = r.Next(0, 90); int b = r.Next(0, 40); g.DrawLine(pp, a, b, (a + 1), (b + 1)); } bit.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); Response.End();
Verification code:
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox> <asp:Image ID="Image1" runat="server" ImageUrl="Default2.aspx" />//这里图片路径不是一张图片的话会默认打开
The above is the watermark and image verification code for Web front-end development shared by the editor. I hope it will be helpful to everyone