保存缩略图通用的函数代码,CSharp代码库,德仔网

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【CSharp】保存缩略图通用的函数

作者:JugeSoft / 发布于2013/10/24/ 513


	/// <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 "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();
	 }
	 }

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　保存缩略图　

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