c# 如何生成自定义图片？c# 生成自定义图片方法-木庄网络博客

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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();
          }
      }