[ATL/WTL]_[0基础]_[CBitmap复制图片-截取图片-平铺图片]

Posted 2020-07-03 phlsheji

场景:

1.当你须要截取图片部分区域作为某个控件的背景。

2.须要平铺图片到一个大区域让他自己主动放大时。

3.或者须要合并图片时。

代码:

	CDC sdc; 
	CDC ddc;
	sdc.CreateCompatibleDC(NULL);
	ddc.CreateCompatibleDC(NULL);
	CBitmap destBmp;
	destBmp.CreateCompatibleBitmap(CClientDC(NULL),width,height);
	sdc.SelectBitmap(m_Bitmap);
	ddc.SelectBitmap(destBmp);
	ddc.BitBlt(0, 0, width, height, sdc, rect.left, rect.top, SRCCOPY );

注意: 这里有一点要注意的。就是destBmp在调用CreateCompatibleBitmap时，传递进去的第一个參数是CClientDC，不然生成的新的CBitmap会不是你想要的.

下边给出的是MFC api复制HBITMAP 对象,部分代码来自网上.

复制HBITMAP对象.

static HBITMAP CopyBitmap(HBITMAP hSourceHbitmap,long width,long height,int srcx,int srcy)
{
	CDC sourceDC;
	CDC destDC;
	sourceDC.CreateCompatibleDC(NULL);
	destDC.CreateCompatibleDC(NULL);
	//The bitmap information.
	BITMAP bm = {0};
	//Get the bitmap information.
	::GetObject(hSourceHbitmap, sizeof(bm), &bm);
	// Create a bitmap to hold the result
	HBITMAP hbmResult = ::CreateCompatibleBitmap(CClientDC(NULL), width, height);

	HBITMAP hbmOldSource = (HBITMAP)::SelectObject( sourceDC.m_hDC, hSourceHbitmap);
	HBITMAP hbmOldDest = (HBITMAP)::SelectObject( destDC.m_hDC, hbmResult );
	destDC.BitBlt(0,0,width, height, sourceDC, srcx, srcy, SRCCOPY );

	// Restore DCs
	::SelectObject( sourceDC.m_hDC, hbmOldSource );
	::SelectObject( destDC.m_hDC, hbmOldDest );
	::DeleteObject(sourceDC.m_hDC);
	::DeleteObject(destDC.m_hDC);

	return hbmResult;
}