C生成缩略图的类

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Drawing; public class PictureSlightly { public PictureSlightly() { // // TODO: Add constructor logic here // } /// <summary> /// 生成缩略图 /// </summary> /// <param name="SourceImage">源图路径(含图片，物理路径)</param> /// <param name="ImageMapth">缩略图路径（含图片，物理路径)</param> /// <param name="width">缩略图宽</param> /// <param name="height">缩略图高</param> public static void MakeImage(string sourceImage, string imageMapth, int width, int height, string mode) { System.Drawing.Image MyImage = System.Drawing.Image.FromFile(sourceImage); int towidth = width; int toheight = height; int x = 0, y = 0; int ow = MyImage.Width; int oh = MyImage.Height; switch (mode) { case "hw": break; case "w": toheight = MyImage.Height * width / MyImage.Width; break; case "h": towidth = MyImage.Width * height / MyImage.Height; break; case "cut": if ((double)MyImage.Width / (double)MyImage.Height > (double)towidth / (double)toheight) { oh = MyImage.Height; ow = MyImage.Width * towidth / toheight; y = 0; x = (MyImage.Width - ow) / 2; } else { ow = MyImage.Width; oh = MyImage.Height * height / toheight; x = 0; y = (MyImage.Height - oh) / 2; }; break; default: break; } System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight); Graphics g = Graphics.FromImage(bitmap); g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.Clear(Color.Transparent); g.DrawImage(MyImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel); try { bitmap.Save(imageMapth, System.Drawing.Imaging.ImageFormat.Jpeg); } catch { } MyImage.Dispose(); bitmap.Dispose(); g.Dispose(); } }

 

g.DrawImage(MyImage, new  Rectangle(0, 0, towidth, toheight),  new  Rectangle(x, y, ow, oh), GraphicsUnit.Pixel); 

这句话将图像实例按新的大小范围进行重新绘制