Asp.net 实现图片缩放 无水印(方法二)
public static System.Drawing.Image GetImage(string path) { try { if (path.StartsWith("http"))//获取远程图片 { System.Net.WebRequest request = System.Net.WebRequest.Create(path); request.Timeout = 10000; System.Net.HttpWebResponse httpresponse = (System.Net.HttpWebResponse)request.GetResponse(); Stream s = httpresponse.GetResponseStream(); return System.Drawing.Image.FromStream(s); } else//获取本地图片 { return System.Drawing.Image.FromFile(path); } } catch (Exception ex) { return null; } } public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode) { System.Drawing.Image originalImage = GetImage(originalImagePath);// System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(originalImagePath)); if (originalImage == null) return; int towidth = width; int toheight = height; int x = 0; int y = 0; int ow = originalImage.Width; int oh = originalImage.Height; if (mode == "EQU")//指定最大高宽,等比例缩放 { //if(height/oh>width/ow),如果高比例多,按照宽来缩放;如果宽的比例多,按照高来缩放 if (height * ow > width * oh) { mode = "W"; } else { mode = "H"; } } 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 System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight); //新建一个画板 System.Drawing.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(System.Drawing.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 System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.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(); } }
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。