C#生成缩略图,C#给图片添加水印

蔚落 2021-06-26 16:06 650阅读 0赞

## 生成缩略图 ##

#region 生成缩略图
            /// <summary>
            /// 生成缩略图
            /// </summary>
            /// <param name="originalImagePath">源图路径（物理路径）</param>
            /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
            /// <param name="width">缩略图宽度</param>
            /// <param name="height">缩略图高度</param>
            /// <param name="mode">生成缩略图的方式</param> 
            public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
            { 
                Image originalImage = Image.FromFile(originalImagePath);
    
                int towidth = width;
                int toheight = height;
    
                int x = 0;
                int y = 0;
                int ow = originalImage.Width;
                int oh = originalImage.Height;
    
                switch (mode)
                { 
                    case "HW"://指定高宽缩放（可能变形）                
                        break;
                    case "WC":
                        if (originalImage.Width > width)
                        { 
                            toheight = originalImage.Height * width / originalImage.Width;
                        }
                        else
                        { 
                            towidth = originalImage.Width;
                            toheight = originalImage.Height;
                        }
                        break;
                    case "W"://指定宽，高按比例                    
                        toheight = originalImage.Height * width / originalImage.Width;
                        break;
                    case "H"://指定高，宽按比例
                        towidth = originalImage.Width * height / originalImage.Height;
                        break;
                    case "Cut"://指定高宽裁减（不变形）                
                        if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                        { 
                            oh = originalImage.Height;
                            ow = originalImage.Height * towidth / toheight;
                            y = 0;
                            x = (originalImage.Width - ow) / 2;
                        }
                        else
                        { 
                            ow = originalImage.Width;
                            oh = originalImage.Width * height / towidth;
                            x = 0;
                            y = (originalImage.Height - oh) / 2;
                        }
                        break;
                    default:
                        break;
                }
    
                //新建一个bmp图片
                Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
    
                //新建一个画板
                Graphics g = System.Drawing.Graphics.FromImage(bitmap);
    
                //设置高质量插值法
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
    
                //设置高质量,低速度呈现平滑程度
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
    
                //清空画布并以透明背景色填充
                g.Clear(Color.Transparent);
    
                //在指定位置并且按指定大小绘制原图片的指定部分
                g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
                    new Rectangle(x, y, ow, oh),
                    GraphicsUnit.Pixel);
    
                try
                { 
                    //以jpg格式保存缩略图
                    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                catch (System.Exception e)
                { 
                    throw e;
                }
                finally
                { 
                    originalImage.Dispose();
                    bitmap.Dispose();
                    g.Dispose();
                }
            }
            #endregion

## 在图片上生成图片水印 ##

#region 在图片上生成图片水印
            /// <summary> 
            /// 在图片上生成图片水印
            /// </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 AddWaterPic(string Path, string Path_syp, string Path_sypf,string style)
            { 
                Path = HttpContext.Current.Server.MapPath(Path);
                Path_syp = HttpContext.Current.Server.MapPath(Path_syp);
    
                System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
                System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
                Graphics g = Graphics.FromImage(image);
                int x=0;
                int y=0;
    
                switch (style)
                { 
                    case "C":
                        x = image.Width/2 - copyImage.Width/2;
                        y = Convert.ToInt32(image.Height * 0.8) - copyImage.Height/2;
                        break;
                    case "RD":
                        x = (image.Width - copyImage.Width) - 20;
                        y = (image.Height - copyImage.Height) - 20;
                        break;
                }
    
                Rectangle rect = new Rectangle(x, y, copyImage.Width, copyImage.Height);
                g.DrawImage(copyImage, rect, 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
                g.Dispose();
    
                image.Save(Path_syp);
                image.Dispose();
            }
            #endregion