static CBrush* PASCAL GetHalftoneBrush();
返回值：如果成功，则返回CBrush对象的指针，否则返回NULL。
说明：
调用该函数获得半色调画刷。半色调画刷使像素颜色在前景色与背景色之间交替，从而形成抖动色调色板。
下面就是半色调画刷创建的抖动色调色板的例子。
请参阅：CBrush
- CWnd::BindProperty
- CWnd::BringWindowToTop
- CWnd::CalcWindowRect
- CWnd::CancelToolTips
- CWnd::CenterWindow
- CWnd::ChangeClipboardChain
- CWnd::CheckDlgButton
- CWnd::CheckRadioButton
- CWnd::ChildWindowFromPoint
- CWnd::ClientToScreen
- CWnd::ContinueModal
- CWnd::Create
- CWnd::CreateCaret
- CWnd::CreateControl
- CWnd::CreateEx
- CWnd::CreateGrayCaret
- CWnd::CreateSolidCaret
- CWnd::CWnd
- CWnd::Default
- CWnd::DefWindowProc
- CWnd::DeleteTempMap
- CWnd::DestroyWindow
- CWnd::Detach
- CWnd::DlgDirList
- CWnd::DlgDirListComboBox