MFC 改變窗體顏色 顏色漸變 內存DC CPaintDC

基本內容來自：http://blog.csdn.net/c__allen/article/details/7704359，我自己加了漸變部分，沒有解決縮放重繪問題，除非在onsize中invalide();

CPaintDC    dc(this);
	CRect rect;
	CDC *pDC = &dc;
	CDC memDC;
	GetClientRect(&rect);
	CBitmap memBitmap;
	memDC.CreateCompatibleDC(NULL);
	memBitmap.CreateCompatibleBitmap(pDC, rect.Width(), rect.Height());
	memDC.SetBkMode(TRANSPARENT);
	memDC.SelectObject(&memBitmap);
	COLORREF bkColor = ::GetSysColor(COLOR_3DFACE);//得到系統顏色  
	memDC.FillSolidRect(rect.left, rect.top, rect.Width(), rect.Height(), bkColor);//繪製背景  
	memDC.FillSolidRect(rect.left, rect.bottom - 40, rect.Width(), rect.Height(), RGB(80, 80, 80));
	/*
	int r1 = 128, g1 = 200, b1 = 200;
	int r2 = 100, g2 = 55, b2 = 165;
	for (int i = 0; i < rect.Width(); i++){
	int r, g, b;
	r = r1 + (i * (r2 - r1) / rect.Width());
	g = g1 + (i * (g2 - g1) / rect.Width());
	b = b1 + (i * (b2 - b1) / rect.Width());
	memDC.FillSolidRect(i, 0, 1, rect.Height(), RGB(r, g, b));
	}*/

	pDC->BitBlt(rect.left, rect.top, rect.Width(), rect.Height(), &memDC, 0, 0, SRCCOPY);
	ReleaseDC(pDC);