我要评论本文实例讲述了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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