C#中不失真生成缩略图

C#中不失真生成缩略图- -

使用.net的方法GetThumbnailImage生成的缩略图失真严重，这里推荐一种不失真生成缩略图的方法，供参考。

/// <summary>

/// 获得缩微图

/// </summary>

/// <returns></returns>

public bool GetThumbImg()

{

try

{

string imgpath; //原始路径

if(imgsourceurl.IndexOf("\",0)<0) //使用的是相对路径

{

imgpath = HttpContext.Current.Server.MapPath(imgsourceurl); //转化为物理路径

}

else

{

imgpath=imgsourceurl;

}

System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(imgpath);

int width = sourceImage.Width;

int height = sourceImage.Height;

if(thumbwidth <= 0)

{

thumbwidth = 120;

}

if(thumbwidth >= width)

{

return false;

}

else

{

(thumbwidth,thHeight*thumbwidth/thWidth,null,IntPtr.Zero);

Image imgThumb=new System.Drawing.Bitmap(thumbwidth,height*thumbwidth/width);

System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(imgThumb);

g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

g.DrawImage(sourceImage, new Rectangle(0, 0, thumbwidth,height*thumbwidth/width), 0, 0, width, height, GraphicsUnit.Pixel);

string thumbpath="";

sourceImage.Dispose();

if(thumburl=="")

{

thumbpath=imgpath;

}

if(thumbpath.IndexOf("\",0)<0)//使用的是相对路径

{

thumbpath=HttpContext.Current.Server.MapPath(thumburl);//转化为物理路径

}

imgThumb.Save(thumbpath,ImageFormat.Jpeg);

imgThumb.Dispose();

return true;

}

}

catch

{

throw;

}

}

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