如何在 MVC C# 中根据主图像或输出图像的大小增加或减少水印图像大小

Question

这里我将两张图片合并为一张图片，一张是水印图片，第二张是要合并水印的主图片或输出图片。

现在我想根据我上传的主图来增减水印图的大小

 public ActionResult WaterMarkImage(HttpPostedFileBase fileToUpload)
            {
                using (Image image = Image.FromStream(fileToUpload.InputStream, true, false))
                {
                    string name = Path.GetFileNameWithoutExtension(fileToUpload.FileName);
                    var ext = Path.GetExtension(fileToUpload.FileName);
                    string myfile = name + ext;
                  
                    var saveImagePath = Path.Combine(Server.MapPath("~/ImgWatermark"), myfile);
                    Image watermarkImage = Image.FromFile(Server.MapPath("/Img/LogoImage2.png"));
                    Watermarker objWatermarker = new Watermarker(image);
    
                    // Set the properties for the logo
                    objWatermarker.Position = WatermarkPosition.Absolute;
                    
                    objWatermarker.PositionX = (int)(image.Width / 2 - watermarkImage.Width / 2);
                    
                    objWatermarker.PositionY = (int)(image.Height / 2 - watermarkImage.Height / 2);
                   
                    objWatermarker.ScaleRatio = 1;
                   
                    objWatermarker.Margin = new Padding(0);
                    
                    objWatermarker.Opacity = 0.5f;
                    
                    objWatermarker.TransparentColor = Color.White;
    
                    // Drawing the logo image on Main image
                    objWatermarker.DrawImage(watermarkImage);
                    
                    objWatermarker.Image.Save(saveImagePath);
    
                    return RedirectToAction("Index", new { imgName = myfile });
                }
            }

Answer 1

我通过将新的“WaterMarkNewHeight”和“WaterMarkNewWidth”传递给 class“resizeImage”解决了问题。

public ActionResult WaterMarkImage(HttpPostedFileBase fileToUpload)
                {
                    using (Image image = Image.FromStream(fileToUpload.InputStream, true, false))
                    {
                        string name = Path.GetFileNameWithoutExtension(fileToUpload.FileName);
                        var ext = Path.GetExtension(fileToUpload.FileName);
                        string myfile = name + ext;
                        //System.Drawing.Image bitmap = image;
                        var saveImagePath = Path.Combine(Server.MapPath("~/ImgWatermark"), myfile);
                        System.Drawing.Image watermarkImage = System.Drawing.Image.FromFile(Server.MapPath("/Img/LogoImage2.png"));
                        Watermarker objWatermarker = new Watermarker(image);
        
                        // Set the properties for the logo
                        objWatermarker.Position = WatermarkPosition.Center;
        
                        objWatermarker.PositionX = (int)(image.Width - watermarkImage.Width) / 2;
        
                        objWatermarker.PositionY = (int)(image.Height - watermarkImage.Height) / 2;
        
                        int WaterMarkNewWidth = image.Width / 2;
                        int WaterMarkNewHeight = image.Height / 4;
        
                        //watermarkImage.Size.Width = WaterMarkNewWidth;
        
        
                        objWatermarker.Margin = new Padding(0);
        
                        objWatermarker.Opacity = 0.4f;
        
                        objWatermarker.TransparentColor = Color.White;
        
                        Image watermarkImage1 = resizeImage(WaterMarkNewWidth, WaterMarkNewHeight, watermarkImage);
        
                        // Draw the logo
                        objWatermarker.DrawImage(watermarkImage1);
                        //Draw the Text
                        //objWatermarker.DrawText("WaterMarkDemo");
        
        
                        objWatermarker.Image.Save(saveImagePath);
        
                        return RedirectToAction("Index", new { imgName = myfile });
                    }
                }
    
    
    public Image resizeImage(int newWidth, int newHeight, Image stPhotoPath)
            {
                Image imgPhoto = stPhotoPath;
    
                int sourceWidth = imgPhoto.Width;
                int sourceHeight = imgPhoto.Height;
    
                //Consider vertical pics
                if (sourceWidth < sourceHeight)
                {
                    int buff = newWidth;
    
                    newWidth = newHeight;
                    newHeight = buff;
                }
    
                int sourceX = 0, sourceY = 0, destX = 0, destY = 0;
                float nPercent = 0, nPercentW = 0, nPercentH = 0;
    
                nPercentW = ((float)newWidth / (float)sourceWidth);
                nPercentH = ((float)newHeight / (float)sourceHeight);
                if (nPercentH < nPercentW)
                {
                    nPercent = nPercentH;
                    destX = System.Convert.ToInt16((newWidth -
                              (sourceWidth * nPercent)) / 2);
                }
                else
                {
                    nPercent = nPercentW;
                    destY = System.Convert.ToInt16((newHeight -
                              (sourceHeight * nPercent)) / 2);
                }
    
                int destWidth = (int)(sourceWidth * nPercent);
                int destHeight = (int)(sourceHeight * nPercent);
    
    
                Bitmap bmPhoto = new Bitmap(newWidth, newHeight,
                              PixelFormat.Format24bppRgb);
    
                bmPhoto.SetResolution(imgPhoto.HorizontalResolution,
                             imgPhoto.VerticalResolution);
    
                Graphics grPhoto = Graphics.FromImage(bmPhoto);
                grPhoto.Clear(Color.White);
                grPhoto.InterpolationMode =
                    System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
    
                grPhoto.DrawImage(imgPhoto,
                    new Rectangle(destX, destY, destWidth, destHeight),
                    new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
                    GraphicsUnit.Pixel);
    
                grPhoto.Dispose();
                imgPhoto.Dispose();
                return bmPhoto;
            }