请问在位图上输出文字时出现白块怎么消除

Question

pDC->SetBkMode(TRANSPARENT);
pDC->TextOut(10,10,"HELLO");

Answer 1

改为如下代码即可：
void CMultDocView::OnDraw(CDC* pDC)
{
CMultDocDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
CBitmap bitmap,*oldbitmap;
BITMAP bm;
bitmap.LoadBitmap(IDB_BITMAP2);
bitmap.GetObject(sizeof(BITMAP),&bm);
CDC memdc;
memdc.CreateCompatibleDC(pDC);
oldbitmap=memdc.SelectObject(&bitmap);
pDC->BitBlt(0,0,bm.bmWidth,bm.bmHeight,&memdc,0,0,SRCCOPY);
pDC->SetBkMode(TRANSPARENT);
pDC->TextOut(10,10,"HELLO");
memdc.SelectObject(oldbitmap);
}