代码如下:
void CProView::OnDraw(CDC* pDC) { CProDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); ///////////////////////////////////////////////////////////////////////////////////////////////////////////////贴图 CBitmap bitmap; bitmap.LoadBitmap(IDB_BITMAP1); CDC dcMemory; dcMemory.CreateCompatibleDC(pDC); // Select the bitmap into the in-memory DC CBitmap* pOldBitmap = dcMemory.SelectObject(&bitmap); // Find a centerpoint for the bitmap in the client area RECT rect; GetClientRect(&rect); // Copy the bits from the in-memory DC into the on- // screen DC to actually do the painting. Use the centerpoint // we computed for the target offset. pDC->BitBlt(0, 0, rect.right, rect.bottom, &dcMemory,0, 0, SRCCOPY); dcMemory.SelectObject(pOldBitmap); }
cdc的方法CreateCompatibleDC:
BOOL CreateCompatibleDC( CDC* pDC );
Creates a memory device context that is compatible with the device specified by pDC.
根据一个dc创建一个相兼容的内存dc。
cdc bitblt:Copies a bitmap from the source device context to this current device context.
BOOL BitBlt( int x, 目标X坐标 int y, 目标Y坐标 int nWidth, 操作范围宽度 int nHeight, 操作范围高度
CDC* pSrcDC,源内容 int xSrc, 源X坐标 int ySrc, 源Y坐标 DWORD dwRop 光栅操作方式);
光栅操作经常是SRCCOPY:将源矩形区域直接拷贝到目标矩形区域。
pDC->BitBlt(0, 0, rect.right, rect.bottom, &dcMemory,0, 0, SRCCOPY);
上面的是以左上角为原点操作。可以找到当前视图中心点进行操作。
CBitmap bmp; bmp.LoadBitmap(IDB_BITMAP1)) Get the size of the bitmap BITMAP bmpInfo; bmp.GetBitmap(&bmpInfo);
// Find a centerpoint for the bitmap in the client area CRect rect; GetClientRect(&rect); int nX = rect.left + (rect.Width() - bmpInfo.bmWidth) / 2; int nY = rect.top + (rect.Height() - bmpInfo.bmHeight) / 2; // Copy the bits from the in-memory DC into the on- // screen DC to actually do the painting. Use the centerpoint // we computed for the target offset. pDC->BitBlt(nX, nY, bmpInfo.bmWidth, bmpInfo.bmHeight, &dcMemory, 0, 0, SRCCOPY);
参考:http://msdn.microsoft.com/en-US/library/kwxzck32(v=vs.80).aspx