using System.Drawing;using System.IO;using System.Drawing.Imaging;using System;namespace treads { /// <summary> /// 生成略缩图 /// </summary> public class Class2 { private Image srcImage; private string srcFileName= @X;//获取图片的路径 private string srcFileName1 = @x;//要保持图片的新路径 /// <summary> /// 回调 /// </summary> /// <returns></returns> public bool ThumbnailCallback() { return false; } /// <summary> /// 保存缩略图 /// </summary> /// <param name=Width></param> /// <param name=Height></param> public void SaveThumbnailImage(int Width, int Height) { switch (Path.GetExtension(srcFileName).ToLower()) { case .png: SaveImage(Width, Height, ImageFormat.Png); break; case .gif: SaveImage(Width, Height, ImageFormat.Gif); break; default: SaveImage(Width, Height, ImageFormat.Jpeg); break; } } /// <summary> /// 生成缩略图并保存 /// </summary> /// <param name=Width>缩略图的宽度</param> /// <param name=Height>缩略图的高度</param> /// <param name=imgformat>保存的图像格式</param> /// <returns>缩略图的Image对象</returns> public void SaveImage(int Width, int Height, ImageFormat imgformat) { srcImage = Image.FromFile(srcFileName); if (imgformat != ImageFormat.Gif && (srcImage.Width > Width) || (srcImage.Height > Height)) { Image img; Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback); img = srcImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero); srcImage.dispose(); img.Save(srcFileName1, imgformat); img.dispose(); } } } }
制作网络下载的略缩图
/// <summary> /// 制作远程缩略图 /// </summary> /// <param name=url>图片URL</param> /// <param name=newFileName>新图路径</param> /// <param name=maxWidth>最大宽度</param> /// <param name=maxHeight>最大高度</param> public static void MakeRemoteThumbnailImage(string url, string newFileName, int maxWidth, int maxHeight) { Stream stream = GetRemoteImage(url); if (stream == null) return; Image original = Image.FromStream(stream); stream.Close(); MakeThumbnailImage(original, newFileName, maxWidth, maxHeight); } /// <summary> /// 获取图片流 /// </summary> /// <param name=url>图片URL</param> /// <returns></returns> private static Stream GetRemoteImage(string url) { HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url); request.Method = GET; request.ContentLength = 0; request.Timeout = 20000; HttpWebResponse response = null; try { response = (HttpWebResponse)request.GetResponse(); return response.GetResponseStream(); } catch { return null; } } /// <summary> /// 裁剪图片并保存 /// </summary> /// <param name=fileName>源图路径(绝对路径)</param> /// <param name=newFileName>缩略图路径(绝对路径)</param> /// <param name=maxWidth>缩略图宽度</param> /// <param name=maxHeight>缩略图高度</param> /// <param name=cropWidth>裁剪宽度</param> /// <param name=cropHeight>裁剪高度</param> /// <param name=X>X轴</param> /// <param name=Y>Y轴</param> public static bool MakeThumbnailImage(string fileName, string newFileName, int maxWidth, int maxHeight, int cropWidth, int cropHeight, int X, int Y) { byte[] imageBytes = File.ReadAllBytes(fileName); Image originalImage = Image.FromStream(new System.IO.MemoryStream(imageBytes)); Bitmap b = new Bitmap(cropWidth, cropHeight); try { using (Graphics g = Graphics.FromImage(b)) { //设置高质量插值法 g.InterpolationMode = InterpolationMode.HighQualityBicubic; //设置高质量,低速度呈现平滑程度 g.SmoothingMode = SmoothingMode.AntiAlias; g.PixelOffsetMode = PixelOffsetMode.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, cropWidth, cropHeight), X, Y, cropWidth, cropHeight, GraphicsUnit.Pixel); Image displayImage = new Bitmap(b, maxWidth, maxHeight); SaveImage(displayImage, newFileName, GetCodecInfo(image/ + GetFormat(newFileName).ToString().ToLower())); return true; } } catch (System.Exception e) { throw e; } finally { originalImage.dispose(); b.dispose(); } }
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