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  • C# 轻松实现水印: 利用原图和水印图的重叠 !!!!

    //##############################################################################
    //图片操作类
    //##############################################################################

    /// <summary>
    /// 获取一个图片按等比例缩小后的大小。
    /// </summary>
    /// <param name="maxWidth">需要缩小到的宽度</param>
    /// <param name="maxHeight">需要缩小到的高度</param>
    /// <param name="imageOriginalWidth">图片的原始宽度</param>
    /// <param name="imageOriginalHeight">图片的原始高度</param>
    /// <returns>返回图片按等比例缩小后的实际大小</returns>
    public static Size GetNewSize(int maxWidth, int maxHeight, int imageOriginalWidth, int imageOriginalHeight)
    {
        
    double w = 0.0;
        
    double h = 0.0;
        
    double sw = Convert.ToDouble(imageOriginalWidth);
        
    double sh = Convert.ToDouble(imageOriginalHeight);
        
    double mw = Convert.ToDouble(maxWidth);
        
    double mh = Convert.ToDouble(maxHeight);

        
    if (sw < mw && sh < mh)
        {
            w 
    = sw;
            h 
    = sh;
        }
        
    else if ((sw / sh) > (mw / mh))
        {
            w 
    = maxWidth;
            h 
    = (w * sh) / sw;
        }
        
    else
        {
            h 
    = maxHeight;
            w 
    = (h * sw) / sh;
        }

        
    return new Size(Convert.ToInt32(w), Convert.ToInt32(h));
    }

    /// <summary>
    /// 对给定的一个图片(Image对象)生成一个指定大小的缩略图。
    /// </summary>
    /// <param name="originalImage">原始图片</param>
    /// <param name="thumMaxWidth">缩略图的宽度</param>
    /// <param name="thumMaxHeight">缩略图的高度</param>
    /// <returns>返回缩略图的Image对象</returns>
    public static System.Drawing.Image GetThumbNailImage(System.Drawing.Image originalImage, int thumMaxWidth, int thumMaxHeight)
    {
        Size thumRealSize 
    = Size.Empty;
        System.Drawing.Image newImage 
    = originalImage;
        Graphics graphics 
    = null;

        
    try
        {
            thumRealSize 
    = GetNewSize(thumMaxWidth, thumMaxHeight, originalImage.Width, originalImage.Height);
            newImage 
    = new Bitmap(thumRealSize.Width, thumRealSize.Height);
            graphics 
    = Graphics.FromImage(newImage);

            graphics.CompositingQuality 
    = CompositingQuality.HighQuality;
            graphics.InterpolationMode 
    = InterpolationMode.HighQualityBicubic;
            graphics.SmoothingMode 
    = SmoothingMode.HighQuality;

            graphics.Clear(Color.Transparent);

            graphics.DrawImage(originalImage, 
    new Rectangle(00, thumRealSize.Width, thumRealSize.Height), new Rectangle(00, originalImage.Width, originalImage.Height), GraphicsUnit.Pixel);
        }
        
    catch { }
        
    finally
        {
            
    if (graphics != null)
            {
                graphics.Dispose();
                graphics 
    = null;
            }
        }

        
    return newImage;
    }
    /// <summary>
    /// 对给定的一个图片文件生成一个指定大小的缩略图。
    /// </summary>
    /// <param name="originalImage">图片的物理文件地址</param>
    /// <param name="thumMaxWidth">缩略图的宽度</param>
    /// <param name="thumMaxHeight">缩略图的高度</param>
    /// <returns>返回缩略图的Image对象</returns>
    public static System.Drawing.Image GetThumbNailImage(string imageFile, int thumMaxWidth, int thumMaxHeight)
    {
        System.Drawing.Image originalImage 
    = null;
        System.Drawing.Image newImage 
    = null;

        
    try
        {
            originalImage 
    = System.Drawing.Image.FromFile(imageFile);
            newImage 
    = GetThumbNailImage(originalImage, thumMaxWidth, thumMaxHeight);
        }
        
    catch { }
        
    finally
        {
            
    if (originalImage != null)
            {
                originalImage.Dispose();
                originalImage 
    = null;
            }
        }

        
    return newImage;
    }
    /// <summary>
    /// 对给定的一个图片文件生成一个指定大小的缩略图,并将缩略图保存到指定位置。
    /// </summary>
    /// <param name="originalImageFile">图片的物理文件地址</param>
    /// <param name="thumbNailImageFile">缩略图的物理文件地址</param>
    /// <param name="thumMaxWidth">缩略图的宽度</param>
    /// <param name="thumMaxHeight">缩略图的高度</param>
    public static void MakeThumbNail(string originalImageFile, string thumbNailImageFile, int thumMaxWidth, int thumMaxHeight)
    {
        System.Drawing.Image newImage 
    = GetThumbNailImage(originalImageFile, thumMaxWidth, thumMaxHeight);
        
    try
        {
            newImage.Save(thumbNailImageFile, ImageFormat.Jpeg);
        }
        
    catch
        { }
        
    finally
        {
            newImage.Dispose();
            newImage 
    = null;
        }
    }
    /// <summary>
    /// 将一个图片的内存流调整为指定大小,并返回调整后的内存流。
    /// </summary>
    /// <param name="originalImageStream">原始图片的内存流</param>
    /// <param name="newWidth">新图片的宽度</param>
    /// <param name="newHeight">新图片的高度</param>
    /// <returns>返回调整后的图片的内存流</returns>
    public static MemoryStream ResizeImage(Stream originalImageStream, int newWidth, int newHeight)
    {
        MemoryStream newImageStream 
    = null;

        System.Drawing.Image newImage 
    = Globals.GetThumbNailImage(System.Drawing.Image.FromStream(originalImageStream), newWidth, newHeight);
        
    if (newImage != null)
        {
            newImageStream 
    = new MemoryStream();
            newImage.Save(newImageStream, ImageFormat.Jpeg);
        }

        
    return newImageStream;
    }
    /// <summary>
    /// 将一个内存流保存为磁盘文件。
    /// </summary>
    /// <param name="stream">内存流</param>
    /// <param name="newFile">目标磁盘文件地址</param>
    public static void SaveStreamToFile(Stream stream, string newFile)
    {
        
    if (stream == null || stream.Length == 0 || string.IsNullOrEmpty(newFile))
        {
            
    return;
        }

        
    byte[] buffer = new byte[stream.Length];
        stream.Position 
    = 0;
        stream.Read(buffer, 
    0, buffer.Length);
        FileStream fileStream 
    = new FileStream(newFile, FileMode.OpenOrCreate, FileAccess.Write);
        fileStream.Write(buffer, 
    0, buffer.Length);
        fileStream.Flush();
        fileStream.Close();
        fileStream.Dispose();
    }
    /// <summary>
    /// 对一个指定的图片加上图片水印效果。
    /// </summary>
    /// <param name="imageFile">图片文件地址</param>
    /// <param name="waterImage">水印图片(Image对象)</param>
    public static void CreateImageWaterMark(string imageFile, System.Drawing.Image waterImage)
    {
        
    if (string.IsNullOrEmpty(imageFile) || !File.Exists(imageFile) || waterImage == null)
        {
            
    return;
        }

        System.Drawing.Image originalImage 
    = System.Drawing.Image.FromFile(imageFile);

        
    if (originalImage.Width - 10 < waterImage.Width || originalImage.Height - 10 < waterImage.Height)
        {
            
    return;
        }

        Graphics graphics 
    = Graphics.FromImage(originalImage);

        
    int x = originalImage.Width - waterImage.Width - 10;
        
    int y = originalImage.Height - waterImage.Height - 10;
        
    int width = waterImage.Width;
        
    int height = waterImage.Height;

        graphics.DrawImage(waterImage, 
    new Rectangle(x, y, width, height), 00, width, height, GraphicsUnit.Pixel);
        graphics.Dispose();

        MemoryStream stream 
    = new MemoryStream();
        originalImage.Save(stream, ImageFormat.Jpeg);
        originalImage.Dispose();

        System.Drawing.Image imageWithWater 
    = System.Drawing.Image.FromStream(stream);

        imageWithWater.Save(imageFile);
        imageWithWater.Dispose();
    }
    /// <summary>
    /// 对一个指定的图片加上文字水印效果。
    /// </summary>
    /// <param name="imageFile">图片文件地址</param>
    /// <param name="waterText">水印文字内容</param>
    public static void CreateTextWaterMark(string imageFile, string waterText)
    {
        
    if (string.IsNullOrEmpty(imageFile) || string.IsNullOrEmpty(waterText) || !File.Exists(imageFile))
        {
            
    return;
        }

        System.Drawing.Image originalImage 
    = System.Drawing.Image.FromFile(imageFile);

        Graphics graphics 
    = Graphics.FromImage(originalImage);

        graphics.SmoothingMode 
    = SmoothingMode.HighQuality;
        graphics.TextRenderingHint 
    = TextRenderingHint.ClearTypeGridFit;
        graphics.CompositingQuality 
    = CompositingQuality.HighQuality;
        graphics.InterpolationMode 
    = InterpolationMode.HighQualityBicubic;

        SolidBrush brush 
    = new SolidBrush(Color.FromArgb(153255255255));
        Font waterTextFont 
    = new Font("Arial"16, FontStyle.Regular);
        SizeF waterTextSize 
    = graphics.MeasureString(waterText, waterTextFont);

        
    float x = (float)originalImage.Width - waterTextSize.Width - 10F;
        
    float y = (float)originalImage.Height - waterTextSize.Height - 10F;

        graphics.DrawString(waterText, waterTextFont, brush, x, y);

        graphics.Dispose();
        brush.Dispose();

        MemoryStream stream 
    = new MemoryStream();
        originalImage.Save(stream, ImageFormat.Jpeg);
        originalImage.Dispose();

        System.Drawing.Image imageWithWater 
    = System.Drawing.Image.FromStream(stream);

        imageWithWater.Save(imageFile);
        imageWithWater.Dispose();
    }

    /// <summary>
    /// 判断上传组件是否包含内容。
    /// </summary>
    /// <param name="fileUpload">ASP.NET 2.0标准上传组件</param>
    /// <returns>如果数据有效,则返回True,否则返回False</returns>
    public static bool IsAttachmentValid(FileUpload fileUpload)
    {
        
    if (fileUpload != null &&
            fileUpload.PostedFile 
    != null &&
            
    !string.IsNullOrEmpty(fileUpload.PostedFile.FileName) &&
            fileUpload.PostedFile.ContentLength 
    > 0)
        {
            
    return true;
        }
        
    return false;
    }

    public class ImageHelper
    {
       
        #region " 水印存放的相对路径 "
        public static string GetLogoPath()
        {
            return "/images/logo.png";    ///水印图路径
        }
        #endregion
       
        #region " 图片水印 "
        // <summary>
        // 在图片上生成图片水印,此方法不支持Gif类型的图片
        // </summary>
        // <param name="Path">原服务器图片路径</param>
        // <param name="Path_syp">生成的带图片水印的图片路径</param>
        // <param name="Path_sypf">水印图片路径</param>
        public static void MarkImage(Stream InUploadImagePath, string inLogoImagePath, string InSavePath)
        {
            System.Drawing.Image Image = System.Drawing.Image.FromStream(InUploadImagePath);
            System.Drawing.Image newimage = Image.FromFile(Current.Server.MapPath(inLogoImagePath));
            Graphics g = Graphics.FromImage(Image);
            g.DrawImage(newimage, new Rectangle(Image.Width - newimage.Width, Image.Height - newimage.Height, newimage.Width, newimage.Height), 0, 0, newimage.Width, newimage.Height, GraphicsUnit.Pixel);
            try {
                Image.Save(Current.Server.MapPath(InSavePath));
            }
            catch (Exception ex) {
            }
            finally {
                g.Dispose();
                Image.Dispose();
                newimage.Dispose();
            }
        }
        #endregion
       
    }

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  • 原文地址:https://www.cnblogs.com/Fooo/p/1320653.html
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