c图片按比例缩放.doc

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1、publicstaticBitmapGetThumbnail(Bitmapb,intdestHeight,intdestWidth)          {                      System.Drawing.ImageimgSource=b;                 System.Drawing.Imaging.ImageFormatthisFormat=imgSource.RawFormat;             intsW=0,sH=0;                   

2、  //按比例缩放                      intsWidth=imgSource.Width;            intsHeight=imgSource.Height;            if(sHeight>destHeight

3、

4、sWidth>destWidth)            {                              if((sWidth*destHeight)>(sHeight*destWidth))                   {   

5、                                 sW=destWidth;                       sH=(destWidth*sHeight)/sWidth;                 }                              else                           {                              sH=destHeight;                       sW=(sWidth*d

6、estHeight)/sHeight;                   }                      }                      else                    {                         sW=sWidth;                 sH=sHeight;             }               BitmapoutBmp=newBitmap(destWidth,destHeight);            

7、 Graphicsg=Graphics.FromImage(outBmp);                 g.Clear(Color.Transparent);                    //设置画布的描绘质量                    g.CompositingQuality=CompositingQuality.HighQuality;            g.SmoothingMode=SmoothingMode.HighQuality;                  g

8、.InterpolationMode=InterpolationMode.HighQualityBicubic;               g.DrawImage(imgSource,newRectangle((destWidth-sW)/2,(destHeight-sH)/2,sW,sH),0,0,imgSource.Width,imgSource.Height,GraphicsUnit.Pixel);                g.Dispose();                 //以下代码为保

9、存图片时，设置压缩质量                EncoderParametersencoderParams=newEncoderParameters();             long[]quality=newlong[1];                 quality[0]=100;                 EncoderParameterencoderParam=newEncoderParameter(System.Drawing.Imaging.Encoder.Quality,qu

10、ality);              encoderParams.Param[0]=encoderParam;              imgSource.Dispose();                    returnoutBmp;             }