MFC Picture Ctrl 无失真自适应显示图片

 1 int height, width;  
 2     CRect rect;//定义矩形类  
 3     CRect rect1;  
 4     CImage image; //创建图片类  
 5     image.Load("test.bmp");  
 6     height = image.GetHeight();  
 7     width = image.GetWidth();  
 8 
 9     m_src.GetClientRect(&rect); //获得pictrue控件所在的矩形区域  
10     CDC *pDc = m_src.GetDC();//获得pictrue控件的Dc  
11     SetStretchBltMode(pDc->m_hDC,STRETCH_HALFTONE);   
12 
13     if(width<=rect.Width() && height<=rect.Width()) //小图片，不缩放  
14     {  
15         rect1 = CRect(rect.TopLeft(), CSize(width,height));  
16         image.StretchBlt(pDc->m_hDC,rect1,SRCCOPY); //将图片画到Picture控件表示的矩形区域  
17         return TRUE;  
18     }  
19     else  
20     {  
21         float xScale=(float)rect.Width()/(float)width;  
22         float yScale=(float)rect.Height()/(float)height;  
23         float ScaleIndex=(xScale>=yScale?xScale:yScale);
24         rect1 = CRect(rect.TopLeft(), CSize((int)width*ScaleIndex,(int)height*ScaleIndex));  
25         image.StretchBlt(pDc->m_hDC,rect1,SRCCOPY); //将图片画到Picture控件表示的矩形区域  
26     }  
27     ReleaseDC(pDc);//释放picture控件的Dc
http://blog.sina.com.cn/s/blog_69b5d2a50101a7qf.html