CMemoryDC

#pragma once

class CMemoryDC:public CDC
{
	CSize m_size;
public:
	
	int GetWidth()const
	{
		return m_size.cx;
	}

	int GetHeight()const
	{
		return m_size.cy;
	}
	void BitTrans(
		int nXDest,		// 目标起点X
		int nYDest,		// 目标起点Y
		int nWidthDest,	// 目标宽度
		int nHeightDest,// 目标高度
		CDC* pDC,		// 目标DC
		int nXSrc,		// 来源起点X
		int nYSrc,		// 来源起点Y
		COLORREF crTrans// 透明色
	)
	{//不拉伸透明
		CMemoryDC dcImage(nWidthDest, nHeightDest, pDC);//临时DC
		CBitmap bmpMask;
		bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);    // 创建单色掩码位图
		CDC dcMask;//掩码DC 
		dcMask.CreateCompatibleDC(pDC);
		dcMask.SelectObject(bmpMask);
		//将载入位图的内存DC中的位图，拷贝到临时DC中
		dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);

		// 设置临时DC的透明色
		dcImage.SetBkColor(crTrans);
		//掩码DC的透明区域为白色其它区域为黑色
		dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);

		//临时DC透明区域为黑色，其它区域保持不变
		dcImage.SetBkColor(RGB(0, 0, 0));
		dcImage.SetTextColor(RGB(255, 255, 255));
		dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);

		// 目标DC透明部分保持屏幕不变，其它部分变成黑色
		pDC->SetBkColor(RGB(255, 255, 255));
		pDC->SetTextColor(RGB(0, 0, 0));
		pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);
		pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);
	}
	void StretchTrans(
		int nXDest,			// 目标起点X
		int nYDest,			// 目标起点Y
		int nWidthDest,     // 目标宽度
		int nHeightDest,    // 目标高度
		CDC* pDC,			// 目标DC
		int nXSrc,			// 来源起点X
		int nYSrc,			// 来源起点Y
		int nWidthSrc,		// 来源宽度
		int nHeightSrc,		// 来源高度
		COLORREF crTrans	// 透明色
	)
	{//拉伸透明
		CMemoryDC dcImage(nWidthDest, nHeightDest, pDC);//临时DC
		CBitmap bmpMask;
		// 创建单色掩码位图
		bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);
		CDC dcMask;
		dcMask.CreateCompatibleDC(pDC);
		dcMask.SelectObject(bmpMask);

		// 将载入位图的内存DC中的位图，拷贝到临时DC中
		if (nWidthDest == nWidthSrc && nHeightDest == nHeightSrc)
			dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);
		else
			dcImage.StretchBlt(0, 0, nWidthDest, nHeightDest,
				this, nXSrc, nYSrc, nWidthSrc, nHeightSrc, SRCCOPY);

		// 设置临时DC的透明色
		dcImage.SetBkColor(crTrans);
		//掩码DC的透明区域为白色其它区域为黑色
		dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);

		//临时DC透明区域为黑色，其它区域保持不变
		dcImage.SetBkColor(RGB(0, 0, 0));
		dcImage.SetTextColor(RGB(255, 255, 255));
		dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);

		// 目标DC透明部分保持屏幕不变，其它部分变成黑色
		pDC->SetBkColor(RGB(255, 255, 255));
		pDC->SetTextColor(RGB(0, 0, 0));
		pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);
		pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);
	}
	BOOL CreateRgn(CRgn& rgn,COLORREF colTrans)
	{//生成透明图区域
		rgn.DeleteObject();//六大GDI对象都通过此函数摧毁（之后句柄变空）
		rgn.CreateRectRgn(0, 0, 0, 0);
		
		int i = -1,cx = m_size.cx,cy=m_size.cy;
		while (++i < cx)//70
		{
			int j = -1;
			while (++j < cy)//80
			{
				if (GetPixel(i, j) != colTrans)
				{
					CRgn r;
					r.CreateRectRgn(i, j, i + 1, j + 1);
					rgn.CombineRgn(&rgn, &r, RGN_OR);
				}
			}
		}
		return TRUE;
	}
	BOOL Create(int cx, int cy, CDC* pDC = NULL)
	{//创建空白内存DC
		CBitmap bmp;
		if (pDC)
			bmp.CreateCompatibleBitmap(pDC, cx, cy);
		else
		{
			CClientDC dc(NULL);
			bmp.CreateCompatibleBitmap(&dc, cx, cy);
		}
		CreateCompatibleDC(pDC);
		SelectObject(&bmp);
		m_size.cx = cx;
		m_size.cy = cy;
		return TRUE;
	}
	BOOL LoadBitmap(LPCTSTR sFile, CDC* pDC = NULL)
	{//加载外部位图
		HGDIOBJ hBitmap = LoadImage(NULL, sFile, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
		if (!hBitmap)
			return FALSE;
		CreateCompatibleDC(pDC);
		SelectObject(hBitmap);
		BITMAP bm;
		GetObject(hBitmap, sizeof(bm), &bm);
		m_size.cx = bm.bmWidth;
		m_size.cy = bm.bmHeight;
		return TRUE;
	}
	BOOL LoadBitmap(UINT nIDBitmap, CDC* pDC = NULL)
	{//加载资源位图
		CreateCompatibleDC(pDC);
		CBitmap bmp;
		bmp.LoadBitmap(nIDBitmap);
		SelectObject(&bmp);
		BITMAP bm;
		bmp.GetBitmap(&bm);
		m_size.cx = bm.bmWidth;
		m_size.cy = bm.bmHeight;
		return TRUE;
	}
	CMemoryDC(int cx, int cy, CDC* pDC = NULL)
	{
		Create(cx, cy, pDC);
	}
	CMemoryDC(UINT nIDBitmap, CDC* pDC = NULL)
	{
		LoadBitmap(nIDBitmap, pDC);
	}
	CMemoryDC(LPCTSTR sFile, CDC* pDC = NULL)
	{
		LoadBitmap(sFile, pDC);
	}	
	
	CMemoryDC()
	{

	}
	~CMemoryDC()
	{
		if (!m_hDC)
			return;
		GetCurrentBitmap()->DeleteObject();
		::DeleteDC(Detach());
	}
};