CDC::StretchBlt函数

Question

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

Answer 1

//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; 

Answer 2

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

Answer 3

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？