C#教程之C#实现为一张大尺寸图片创建缩略图的方

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C#教程之C#实现为一张大尺寸图片创建缩略图的方

本文实例讲述了C#实现为一张大尺寸图片创建缩略图的方法。分享给大家供大家参考。具体实现方法如下：

								public static Bitmap CreateThumbnail(string lcFilename, int lnWidth, int lnHeight)

								{

								  System.Drawing.Bitmap bmpOut = null;

								  try

								  {

								    Bitmap loBMP = new Bitmap(lcFilename);

								    ImageFormat loFormat = loBMP.RawFormat;

								    decimal lnRatio;

								    int lnNewWidth = 0;

								    int lnNewHeight = 0;

								    //*** If the image is smaller than a thumbnail just return it

								    if (loBMP.Width < lnWidth && loBMP.Height < lnHeight)

								      return loBMP;

								    if (loBMP.Width > loBMP.Height)

								    {

								      lnRatio = (decimal)lnWidth / loBMP.Width;

								      lnNewWidth = lnWidth;

								      decimal lnTemp = loBMP.Height * lnRatio;

								      lnNewHeight = (int)lnTemp;

								    }

								    else

								    {

								      lnRatio = (decimal)lnHeight / loBMP.Height;

								      lnNewHeight = lnHeight;

								      decimal lnTemp = loBMP.Width * lnRatio;

								      lnNewWidth = (int)lnTemp;

								    }

								    bmpOut = new Bitmap(lnNewWidth, lnNewHeight);

								    Graphics g = Graphics.FromImage(bmpOut);

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

								    g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight);

								    g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight);

								    loBMP.Dispose();

								  }

								  catch

								  {

								    return null;

								  }

								  return bmpOut;

								}

希望本文所述对大家的C#程序设计有所帮助。

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