实用开发一：c#封装好的处理图片的水印和生成缩略图的类

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.IO;

/**//// <summary>
/// ImgWater 的摘要说明
/// </summary>
public class ImgWater
...{

    /**//// <summary>
    /// 图片水印
    /// </summary>
    /// <param name="ImgFile">原图文件地址</param>
    /// <param name="WaterImg">水印图片地址</param>
    /// <param name="sImgPath">水印图片保存地址</param>
    /// <param name="Alpha">水印透明度设置</param>
    /// <param name="iScale">水印图片在原图上的显示比例</param>
    /// <param name="intDistance">水印图片在原图上的边距确定,以图片的右边和下边为准,当设定的边距超过一定大小后参数会自动失效</param>
    public void zzsImgWater(
         string ImgFile
        , string WaterImg
        , string sImgPath
        , float Alpha
        , float iScale
        , int intDistance
        )
    ...{
        try
        ...{

            //装载图片


            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);



            //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);



            int imgPhotoWidth = imgPhoto.Width;
            int imgPhotoHeight = imgPhoto.Height;

            System.Drawing.Image imgWatermark = new Bitmap(WaterImg);
            int imgWatermarkWidth = imgWatermark.Width;
            int imgWatermarkHeight = imgWatermark.Height;


            //计算水印图片尺寸

            decimal aScale = Convert.ToDecimal(iScale);
            decimal pScale = 0.05M;
            decimal MinScale = aScale - pScale;
            decimal MaxScale = aScale + pScale;

            int imgWatermarkWidthNew = imgWatermarkWidth;
            int imgWatermarkHeightNew = imgWatermarkHeight;

            if (imgPhotoWidth >= imgWatermarkWidth && imgPhotoHeight >= imgWatermarkHeight && imgPhotoWidth >= imgPhotoHeight)
                if (imgWatermarkWidth > imgWatermarkHeight)

                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                        imgWatermarkHeightNew = Convert.ToInt32((imgPhotoWidth * aScale / imgWatermarkWidth) * imgWatermarkHeight);
                    }
                else
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                        imgWatermarkWidthNew = Convert.ToInt32((imgPhotoHeight * aScale / imgWatermarkHeight) * imgWatermarkWidth);
                    }
            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgWatermarkWidth >= imgWatermarkHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight <= imgPhotoHeight && imgPhotoWidth >= imgPhotoHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth <= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgPhotoWidth >= imgPhotoHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }

            if (imgPhotoWidth >= imgWatermarkWidth && imgPhotoHeight >= imgWatermarkHeight && imgPhotoWidth <= imgPhotoHeight)
                if (imgWatermarkWidth > imgWatermarkHeight)
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                        imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
                    }
                else
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                        imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
                    }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgWatermarkWidth <= imgWatermarkHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight <= imgPhotoHeight && imgPhotoWidth <= imgPhotoHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth <= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgPhotoWidth <= imgPhotoHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }


            //将原图画出来

            Bitmap bmPhoto = new Bitmap(imgPhotoWidth, imgPhotoHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            bmPhoto.SetResolution(72, 72);
            Graphics gbmPhoto = Graphics.FromImage(bmPhoto);

            gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            gbmPhoto.Clear(Color.White);
            gbmPhoto.DrawImage(
                  imgPhoto
                , new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight)
                , 0
                , 0
                , imgPhotoWidth
                , imgPhotoHeight
                , GraphicsUnit.Pixel
                );



            Bitmap bmWatermark = new Bitmap(bmPhoto);
            bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            Graphics gWatermark = Graphics.FromImage(bmWatermark);

            //指定高质量显示水印图片质量
            gWatermark.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gWatermark.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;


            System.Drawing.Imaging.ImageAttributes imageAttributes = new System.Drawing.Imaging.ImageAttributes();

            //设置两种颜色,达到合成效果

            System.Drawing.Imaging.ColorMap colorMap = new System.Drawing.Imaging.ColorMap();
            colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

            System.Drawing.Imaging.ColorMap[] remapTable = ...{ colorMap };

            imageAttributes.SetRemapTable(remapTable, System.Drawing.Imaging.ColorAdjustType.Bitmap);

            //用矩阵设置水印图片透明度
            float[][] colorMatrixElements = ...{ 
               new float[] ...{1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  0.0f,  0.0f,  Alpha, 0.0f},
               new float[] ...{0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
            };


            System.Drawing.Imaging.ColorMatrix wmColorMatrix = new System.Drawing.Imaging.ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(wmColorMatrix, System.Drawing.Imaging.ColorMatrixFlag.Default, System.Drawing.Imaging.ColorAdjustType.Bitmap);

            //确定水印边距
            int xPos = imgPhotoWidth - imgWatermarkWidthNew;
            int yPos = imgPhotoHeight - imgWatermarkHeightNew;
            int xPosOfWm = 0;
            int yPosOfWm = 0;

            if (xPos > intDistance)
                xPosOfWm = xPos - intDistance;
            else
                xPosOfWm = xPos;

            if (yPos > intDistance)
                yPosOfWm = yPos - intDistance;
            else
                yPosOfWm = yPos;

            gWatermark.DrawImage(
                  imgWatermark
                , new Rectangle(xPosOfWm, yPosOfWm, imgWatermarkWidthNew, imgWatermarkHeightNew)
                , 0
                , 0
                , imgWatermarkWidth
                , imgWatermarkHeight
                , GraphicsUnit.Pixel
                , imageAttributes
                );

            imgPhoto = bmWatermark;



            //以jpg格式保存图片
            imgPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

            //销毁对象
            gbmPhoto.Dispose();
            gWatermark.Dispose();

            imgPhoto.Dispose();
            imgWatermark.Dispose();



        }
        catch (Exception ex)
        ...{
        }
    }


    /**//// <summary>
    /// 文字水印
    /// </summary>
    /// <param name="ImgFile">原图文件地址</param>
    /// <param name="TextFont">水印文字</param>
    /// <param name="sImgPath">文字水印图片保存地址</param>
    /// <param name="hScale">高度位置</param>
    /// <param name="widthFont">文字块在图片中所占宽度比例</param>
    /// <param name="Alpha">文字透明度 其数值的范围在0到255</param>

    public void zzsTextWater(
          string ImgFile
        , string TextFont
        , string sImgPath
        , float hScale
        , float widthFont
        , int Alpha
        )
    ...{
        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);



            //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);

            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.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("arial", 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);

            //if (xCenterOfImg<crSize.Height)
            //    xCenterOfImg = (imgPhotoWidth * (1 - (crSize.Height)/ imgPhotoWidth));

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

            //
            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();
        }
        catch (Exception ex)
        ...{
        }
    }


    /**//// <summary>
    /// 文字和Logo图片水印
    /// </summary>
    /// <param name="ImgFile">原图文件地址</param>
    /// <param name="WaterImg">水印图片地址</param>
    /// <param name="TextFont">水印文字信息</param>
    /// <param name="sImgPath">生存水印图片后的保存地址</param>
    /// <param name="ImgAlpha">水印图片的透明度</param>
    /// <param name="imgiScale">水印图片在原图上的显示比例</param>
    /// <param name="intimgDistance">水印图片在原图上的边距确定,以图片的右边和下边为准,当设定的边距超过一定大小后参数会自动失效</param>
    /// <param name="texthScale">水印文字高度位置,从图片底部开始计算，0－1</param>
    /// <param name="textwidthFont">文字块在图片中所占宽度比例 0－1</param>
    /// <param name="textAlpha">文字透明度 其数值的范围在0到255</param>
    public void zzsImgTextWater(
          string ImgFile
        , string WaterImg
        , string TextFont
        , string sImgPath
        , float ImgAlpha
        , float imgiScale
        , int intimgDistance
        , float texthScale
        , float textwidthFont
        , int textAlpha
        )
    ...{
        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);



            //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);


            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.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("arial", sizes[i], FontStyle.Bold);
                crSize = gbmPhoto.MeasureString(TextFont, crFont);

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

            //设置水印字体的位置
            int yPixlesFromBottom = (int)(imgPhotoHeight * texthScale);
            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;

            //
            System.Drawing.SolidBrush semiTransBrush2 = new System.Drawing.SolidBrush(Color.FromArgb(textAlpha, 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(textAlpha, 255, 255, 255));

            gbmPhoto.DrawString(
                  TextFont
                , crFont
                , semiTransBrush
                , new System.Drawing.PointF(xCenterOfImg, yPosFromBottom)
                , StrFormat
                );


            System.Drawing.Image imgWatermark = new Bitmap(WaterImg);
            int imgWatermarkWidth = imgWatermark.Width;
            int imgWatermarkHeight = imgWatermark.Height;


            //计算水印图片尺寸

            decimal aScale = Convert.ToDecimal(imgiScale);
            decimal pScale = 0.05M;
            decimal MinScale = aScale - pScale;
            decimal MaxScale = aScale + pScale;

            int imgWatermarkWidthNew = imgWatermarkWidth;
            int imgWatermarkHeightNew = imgWatermarkHeight;

            if (imgPhotoWidth >= imgWatermarkWidth && imgPhotoHeight >= imgWatermarkHeight && imgPhotoWidth >= imgPhotoHeight)
                if (imgWatermarkWidth > imgWatermarkHeight)

                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                        imgWatermarkHeightNew = Convert.ToInt32((imgPhotoWidth * aScale / imgWatermarkWidth) * imgWatermarkHeight);
                    }
                else
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                        imgWatermarkWidthNew = Convert.ToInt32((imgPhotoHeight * aScale / imgWatermarkHeight) * imgWatermarkWidth);
                    }
            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgWatermarkWidth >= imgWatermarkHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight <= imgPhotoHeight && imgPhotoWidth >= imgPhotoHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth <= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgPhotoWidth >= imgPhotoHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }

            if (imgPhotoWidth >= imgWatermarkWidth && imgPhotoHeight >= imgWatermarkHeight && imgPhotoWidth <= imgPhotoHeight)
                if (imgWatermarkWidth > imgWatermarkHeight)
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkWidth) / Convert.ToDecimal(imgPhotoWidth)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                        imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
                    }
                else
                    if ((MinScale <= Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7)) && (Math.Round((Convert.ToDecimal(imgWatermarkHeight) / Convert.ToDecimal(imgPhotoHeight)), 7) <= MaxScale))
                    ...{

                    }
                    else
                    ...{
                        imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                        imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
                    }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgWatermarkWidth <= imgWatermarkHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }

            if (imgWatermarkWidth >= imgPhotoWidth && imgWatermarkHeight <= imgPhotoHeight && imgPhotoWidth <= imgPhotoHeight)
            ...{
                imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                imgWatermarkHeightNew = Convert.ToInt32(((imgPhotoWidth * aScale) / imgWatermarkWidth) * imgWatermarkHeight);
            }

            if (imgWatermarkWidth <= imgPhotoWidth && imgWatermarkHeight >= imgPhotoHeight && imgPhotoWidth <= imgPhotoHeight)
            ...{
                imgWatermarkHeightNew = Convert.ToInt32(imgPhotoHeight * aScale);
                imgWatermarkWidthNew = Convert.ToInt32(((imgPhotoHeight * aScale) / imgWatermarkHeight) * imgWatermarkWidth);
            }


            //将原图画出来


            Bitmap bmWatermark = new Bitmap(bmPhoto);
            bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            Graphics gWatermark = Graphics.FromImage(bmWatermark);

            //指定高质量显示水印图片质量
            gWatermark.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gWatermark.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;


            System.Drawing.Imaging.ImageAttributes imageAttributes = new System.Drawing.Imaging.ImageAttributes();

            //设置两种颜色,达到合成效果

            System.Drawing.Imaging.ColorMap colorMap = new System.Drawing.Imaging.ColorMap();
            colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

            System.Drawing.Imaging.ColorMap[] remapTable = ...{ colorMap };

            imageAttributes.SetRemapTable(remapTable, System.Drawing.Imaging.ColorAdjustType.Bitmap);

            //用矩阵设置水印图片透明度
            float[][] colorMatrixElements = ...{ 
               new float[] ...{1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
               new float[] ...{0.0f,  0.0f,  0.0f,  ImgAlpha, 0.0f},
               new float[] ...{0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
            };


            System.Drawing.Imaging.ColorMatrix wmColorMatrix = new System.Drawing.Imaging.ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(wmColorMatrix, System.Drawing.Imaging.ColorMatrixFlag.Default, System.Drawing.Imaging.ColorAdjustType.Bitmap);

            //确定水印边距
            int xPos = imgPhotoWidth - imgWatermarkWidthNew;
            int yPos = imgPhotoHeight - imgWatermarkHeightNew;
            int xPosOfWm = 0;
            int yPosOfWm = 0;

            if (xPos > intimgDistance)
                xPosOfWm = xPos - intimgDistance;
            else
                xPosOfWm = xPos;

            if (yPos > intimgDistance)
                yPosOfWm = yPos - intimgDistance;
            else
                yPosOfWm = yPos;

            gWatermark.DrawImage(
                  imgWatermark
                , new Rectangle(xPosOfWm, yPosOfWm, imgWatermarkWidthNew, imgWatermarkHeightNew)
                , 0
                , 0
                , imgWatermarkWidth
                , imgWatermarkHeight
                , GraphicsUnit.Pixel
                , imageAttributes
                );

            imgPhoto = bmWatermark;

            //以jpg格式保存图片
            imgPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

            //销毁对象
            gbmPhoto.Dispose();
            gWatermark.Dispose();
            bmPhoto.Dispose();
            imgPhoto.Dispose();
            imgWatermark.Dispose();
        }
        catch (Exception ex)
        ...{
        }
    }

    /**//// <summary>
    /// 缩略图
    /// </summary>
    /// <param name="ImgFile">原图文件地址</param>
    /// <param name="sImgPath">缩略图保存地址</param>
    /// <param name="ResizeWidth">缩略图宽度</param>
    /// <param name="ResizeHeight">缩略图高度</param>
    /// <param name="BgColor">缩略图背景颜色,注意,背景颜色只能指定KnownColor中的值,如blue,red,green等</param>

    public void zzsResizeImg(
          string ImgFile
        , string sImgPath
        , int ResizeWidth
        , int ResizeHeight
        , string BgColor
        )
    ...{
        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);



            //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);


            int imgPhotoWidth = imgPhoto.Width;
            int imgPhotoHeight = imgPhoto.Height;
            int startX = 0;
            int StartY = 0;
            int NewWidth = 0;
            int NewHeight = 0;

            if (imgPhotoWidth >= ResizeWidth && imgPhotoHeight >= ResizeHeight)
            ...{
                NewWidth = ResizeWidth;
                NewHeight = Convert.ToInt32(imgPhotoHeight * Math.Round(Convert.ToDecimal(ResizeWidth) / Convert.ToDecimal(imgPhotoWidth), 10));
                startX = 0;
                StartY = (ResizeHeight - NewHeight) / 2;
            }

            if (ResizeWidth > imgPhotoWidth && ResizeHeight < imgPhotoHeight)
            ...{
                NewHeight = ResizeHeight;
                NewWidth = Convert.ToInt32(imgPhotoWidth * Math.Round(Convert.ToDecimal(ResizeHeight) / Convert.ToDecimal(imgPhotoHeight), 10));
                startX = (ResizeWidth - NewWidth) / 2;
                StartY = 0;
            }

            if (ResizeWidth < imgPhotoWidth && ResizeHeight > imgPhotoHeight)
            ...{
                NewWidth = ResizeWidth;
                NewHeight = Convert.ToInt32(imgPhotoHeight * Math.Round(Convert.ToDecimal(ResizeWidth) / Convert.ToDecimal(imgPhotoWidth), 10));
                startX = 0;
                StartY = (ResizeHeight - NewHeight) / 2;
            }

            if (imgPhotoWidth < ResizeWidth && imgPhotoHeight < ResizeHeight)
            ...{
                NewWidth = imgPhotoWidth;
                NewHeight = imgPhotoHeight;
                startX = (ResizeWidth - imgPhotoWidth) / 2;
                StartY = (ResizeHeight - imgPhotoHeight) / 2;
            }

            //计算缩放图片尺寸



            Bitmap bmPhoto = new Bitmap(ResizeWidth, ResizeHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            bmPhoto.SetResolution(72, 72);
            Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
            gbmPhoto.Clear(Color.FromName(BgColor));
            gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            gbmPhoto.DrawImage(
                  imgPhoto
                , new Rectangle(startX, StartY, NewWidth, NewHeight)
                , new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight)
                , GraphicsUnit.Pixel
                );
            bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            imgPhoto.Dispose();
            gbmPhoto.Dispose();
            bmPhoto.Dispose();
        }
        catch (Exception err)
        ...{
        }
    }

    /**//// <summary>
    /// 图片剪切
    /// </summary>
    /// <param name="ImgFile">原图文件地址</param>
    /// <param name="sImgPath">缩略图保存地址</param>
    /// <param name="PointX">剪切起始点 X坐标</param>
    /// <param name="PointY">剪切起始点 Y坐标</param>
    /// <param name="CutWidth">剪切宽度</param>
    /// <param name="CutHeight">剪切高度</param>

    public void zzsCutImg(
          string ImgFile
        , string sImgPath
        , int PointX
        , int PointY
        , int CutWidth
        , int CutHeight
        )
    ...{
        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);

            //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);
//此处只能用filestream，用 System.Drawing.Image则会报多过进程访问文件的错误，会锁定文件
            Bitmap bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            bmPhoto.SetResolution(72, 72);
            Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
            gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            gbmPhoto.DrawImage(
                  imgPhoto
                , new Rectangle(0, 0, CutWidth, CutHeight)
                , new Rectangle(PointX, PointY, CutHeight, CutHeight)
                , GraphicsUnit.Pixel
                );
            bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            imgPhoto.Dispose();
            gbmPhoto.Dispose();
            bmPhoto.Dispose();
        }
        catch (Exception err)
        ...{
        }
    }
}

调用示例： 

//取的新图片文件的名称
                string namestr = MakedownName();
                newname = namestr + "." + objFile.ImageType;
                objFile.SaveAsVirtual("/Function/UpLoadPic/Temp_Pic/" + newname);
                string sourcepath = Server.MapPath("/Function/UpLoadPic/Temp_Pic/" + newname);
                string smallimg = Server.MapPath("/Function/UpLoadPic/Temp_Pic/Small/" + namestr + ".jpg");
                string bigimg = Server.MapPath("/Function/UpLoadPic/Temp_Pic/Big/" + namestr + ".jpg");
                string waterlogo = Server.MapPath("/Function/UpLoadPic/sys_logo.gif");
                //保存图片

                //objFile.SaveAsVirtual(common.TmpProdImgVirtPath + newname);

                //保存图片名称
                if (Pic_type == "single")
                    Session["UploadPic"] = namestr + ".jpg";
                else
                    Session["UploadPic" + Pic_type] = namestr + ".jpg";

                //生成小缩略图
                //WaterMarksmall(objFile.ImageWidth, objFile.ImageHeight);
                ImgWater myimgwater = new ImgWater();
                myimgwater.zzsResizeImg(sourcepath, smallimg, pic_width, pic_height, "white");
                //添加水印效果

                if (Watermark.Checked)//添加水印效果
                    //myimgwater.zzsTextWater(sourcepath, "www.168ec.com", bigimg, 0.1f, 0.3f, 50);
                    myimgwater.zzsImgWater(sourcepath, waterlogo, bigimg, 0.3f, 0.2f, 20);

 

效果：http://www.168ec.com/App_web/Share/Show_business.aspx?id=399213