c#生成自定义图片方法代码实例
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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();
}
}
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