图片水印与文字水印

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
using System.IO;

// Draw the image in the bottom-right corner 图片右下角
using (System.Drawing.Image watermark = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath("~/Gfx/Watermark.png")))
{
    using (Graphics g = Graphics.FromImage(args.Image))
    {
        // Setup the quality settings (max)
        g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

        // Draw the image
        g.DrawImageUnscaled(watermark, args.Image.Width - watermark.Width, args.Image.Height - watermark.Height, watermark.Width, watermark.Height);

        g.Dispose();
    }
}

// Draw the text in the bottom-right corner
using (Graphics g = Graphics.FromImage(args.Image))
{
    string text = "MyLogo";
    Font font = new Font(FontFamily.GenericSansSerif, 14, FontStyle.Bold);
    SizeF stringSize = g.MeasureString(text, font);
    PointF location = new PointF(args.Image.Width - stringSize.Width - 10, args.Image.Height - stringSize.Height - 10);

    // Setup the quality settings
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

    // Draw the text
    g.DrawString(text, font, Brushes.Red, location);

    g.Dispose();
}

水印在图片中心 这个图只截取了一部分

using (Graphics g = Graphics.FromImage(args.Image))
{
    // Draw a horizontal text in the image center
    string text = "My NEW watermark";
    Font font = new Font(FontFamily.GenericSansSerif, 24, FontStyle.Bold);
    SizeF stringSize = g.MeasureString(text, font);
    PointF location = new PointF((args.Image.Width - stringSize.Width) / 2, (args.Image.Height - stringSize.Height) / 2);
    
    // Setup the quality settings
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

    // Draw the text
    g.DrawString(text, font, new SolidBrush(Color.FromArgb(85, 255, 255, 80)), location);

    // Draw a vertical text in the bottom-right corner
    DateTime dt = DateTime.UtcNow;
    text = "My watermark - " + dt.ToString("s");
    font = new Font(FontFamily.GenericSansSerif, 9, FontStyle.Bold);
    StringFormat stringFormat = new StringFormat();
    stringFormat.FormatFlags = StringFormatFlags.DirectionVertical;
    stringSize = g.MeasureString(text, font, 100, stringFormat);
    location = new PointF(args.Image.Width - stringSize.Width - 5, args.Image.Height - stringSize.Height - 5);

    // Draw another text
    g.DrawString(text, font, new SolidBrush(Color.FromArgb(80, 255, 255, 255)), location, stringFormat);

    g.Dispose();
}