public class BitmapHelper { /// <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, string type) { 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 " 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; case " DB ": // 等比缩放（不变形，如果高大按高，宽大按宽缩放） if (( double)originalImage.Width / ( double)towidth < ( double)originalImage.Height / ( double)toheight) { toheight = height; towidth = originalImage.Width * height / originalImage.Height; } else { towidth = width; toheight = originalImage.Height * width / originalImage.Width; } break; default: break; } // 新建一个bmp图片 Image bitmap = new Bitmap(towidth, toheight); // 新建一个画板 Graphics g = 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 { // 保存缩略图 if (type.ToUpper() == " JPG ") { bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg); } if (type.ToUpper() == " BMP ") { bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Bmp); } if (type.ToUpper() == " GIF ") { bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Gif); } if (type.ToUpper() == " PNG ") { bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Png); } } catch (System.Exception e) { throw e; } finally { originalImage.Dispose(); bitmap.Dispose(); g.Dispose(); } } /**/ /// <summary> /// 在图片上增加文字水印 /// </summary> /// <param name="Path"> 原服务器图片路径 </param> /// <param name="Path_sy"> 生成的带文字水印的图片路径 </param> public static void AddShuiYinWord( string Path, string Path_sy) { string addText = " Sxmobi "; Image image = Image.FromFile(Path); Graphics g = Graphics.FromImage(image); g.DrawImage(image, 0, 0, image.Width, image.Height); Font f = new Font( " Verdana ", 16); Brush b = new SolidBrush(Color.Blue); g.DrawString(addText, f, b, 15, 15); g.Dispose(); image.Save(Path_sy); image.Dispose(); } /**/ /// <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 AddShuiYinPic( string Path, string Path_syp, string Path_sypf) { Image image = Image.FromFile(Path); Image copyImage = Image.FromFile(Path_sypf); Graphics g = Graphics.FromImage(image); g.DrawImage(copyImage, new Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel); g.Dispose(); image.Save(Path_syp); image.Dispose(); } }