public class imgTextWater
{
 public imgTextWater()
 {
  //
  // TODO: 在此处添加构造函数逻辑
  //
 }
    public bool TextWater(string ImgFile, string TextFont, string sImgPath, int Alpha, float widthFont, float hScale)
    {
        try
        {
            FileStream fs = new FileStream(ImgFile, FileMode.Open);
            BinaryReader br = new BinaryReader(fs);
            byte[] bytes = br.ReadBytes((int)fs.Length);
            br.Close();
            fs.Close();
            MemoryStream ms = new MemoryStream(bytes);

            System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);
            int imgPhotoWidth = imgPhoto.Width;
            int imgPhotoHeight = imgPhoto.Height;

            Bitmap bmPhoto = new Bitmap(imgPhotoWidth, imgPhotoHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            bmPhoto.SetResolution(72, 72);
            Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
            gbmPhoto.Clear(Color.FromName("white"));//gif背景色
            gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight), 0, 0, imgPhotoWidth, imgPhotoHeight, GraphicsUnit.Pixel);

            //建立字体大小的数组,循环找出适合图片的水印字体
            int[] sizes = new int[] { 1000, 800, 700, 650, 600, 560, 540, 500, 450, 400, 380, 360, 340, 320, 300, 280, 260, 240, 220, 200, 180, 160, 140, 120, 100, 80, 72, 64, 48, 32, 28, 26, 24, 20, 28, 16, 14, 12, 10, 8, 6, 4, 2 };
            System.Drawing.Font crFont = null;
            System.Drawing.SizeF crSize = new SizeF();
            for (int i = 0; i < 43; i++)
            {
                crFont = new Font("黑体", sizes[i], FontStyle.Bold);
                crSize = gbmPhoto.MeasureString(TextFont, crFont);

                if ((ushort)crSize.Width < (ushort)imgPhotoWidth * widthFont)
                    break;
            }

            //设置水印字体的位置
            int yPixlesFromBottom = (int)(imgPhotoHeight * hScale);
            float yPosFromBottom = ((imgPhotoHeight - yPixlesFromBottom) - (crSize.Height / 2));
            float xCenterOfImg = (imgPhotoWidth * 1 / 2);

            System.Drawing.StringFormat StrFormat = new System.Drawing.StringFormat();
            StrFormat.Alignment = System.Drawing.StringAlignment.Center;

            //画两次制造透明效果
            System.Drawing.SolidBrush semiTransBrush2 = new System.Drawing.SolidBrush(Color.FromArgb(Alpha, 0, 0, 0));
            gbmPhoto.DrawString(TextFont, crFont, semiTransBrush2, new System.Drawing.PointF(xCenterOfImg + 1, yPosFromBottom + 1), StrFormat);

            System.Drawing.SolidBrush semiTransBrush = new System.Drawing.SolidBrush(Color.FromArgb(Alpha, 255, 255, 255));
            gbmPhoto.DrawString(TextFont, crFont, semiTransBrush, new System.Drawing.PointF(xCenterOfImg, yPosFromBottom), StrFormat);

            bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

            gbmPhoto.Dispose();
            imgPhoto.Dispose();
            bmPhoto.Dispose();

            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }

}

调用方法：

imgTextWater imgWater = new imgTextWater();
imgWater.TextWater(“d:\img\201029348485.jpg”, "水印的文字", “d:\img\201029348485.jpg”, 60,0.7f,0.55f);

OK了，这样图片就变成有水印文字了。

• 本文标题： ASP.NET上传图片添加文字水印，大小根据图片自动缩放长宽比例
• 文章分类：【.NET/Web】
• 非特殊说明，本文版权归【胡同里的砖头】个人博客 所有，转载请注明出处.

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