CDC::StretchBlt函数

[bkbj]

我在一个picture控件上面放一副位图文件，用到StretchBlt函数，目的是要使位图能够自适应picture控件的大小，代码如下：
pDC->StretchBlt(0,0,bminfo.bmWidth,bminfo.bmHeight,&dcComp,rect.left,rect.top,rect.right-rect.left,rect.bottom-rect.top,SRCCOPY);

其中rect为picture控件的矩形区域，可是仍然无法实现图片自适应picture控件大小，MSDN上面说有个CDC::SetStretchBltMode函数，可是我试了好像不管用，请问应该怎么做？谢

[kane_yj]

pDC->StretchBlt(0, 0, rect.Width(), rect.Height(),
,&dcComp, 0, 0, bminfo.bmWidth, bminfo.bmHeight,SRCCOPY );

你的参数写反了，先目的后源的

[Julienjut]

//GetWindowRect(&WndRect);
//ClientToScreen(&WndRect);
CRect WndRect;
WndRect.top=50;
WndRect.left=20;
WndRect.right=300;
WndRect.bottom=650;

CDC * pmem,*pMiddle;
CBitmap * pbit;
CBitmap * pold,*pMiddleOld;
BITMAP BitMap;
CBitmap *pNewBitmap=new CBitmap;
pmem=new CDC;
pMiddle=new CDC;
pbit=new CBitmap;
pbit->LoadBitmap(IDB_MAINBKGROUND);

pmem->CreateCompatibleDC(pDC);
pMiddle->CreateCompatibleDC(pDC);

pold=(CBitmap *) pmem->SelectObject(pbit);
pbit->GetObject(sizeof(BitMap),&BitMap);
pNewBitmap->CreateCompatibleBitmap(pDC,iWidth,iHeight);
pMiddleOld=(CBitmap *)pMiddle->SelectObject(pNewBitmap);
pMiddle->StretchBlt(0,0,iWidth,iHeight,pmem,0,0,BitMap.bmWidth,BitMap.bmHeight,SRCCOPY);
pDC->BitBlt(WndRect.left,WndRect.top,iWidth,iHeight,pMiddle,0,0,SRCCOPY);
delete pMiddle->SelectObject(pMiddleOld);
delete pMiddle;
delete pmem->SelectObject(pold);
delete pmem;

[Julienjut]

补充一下，把 iWidth,iHeight 换成 WndRect.Width(),WndRect.Height()

[bkbj]

我用GetWindowRect(&rect)取得了一个举行区域rect，然后ClientToScreen(&rect)，最后StretchBlt，可是图象不显示，当我把ClientToScreen换成ScreenToClient时显示出图象了，但是不是刚好在picture上，而是有点偏往左下角，这是怎么回事？到底应该用ClientToScreen了，还是应该用ScreenToClient？

[meifen]

ok