如果我在多显示器系统上有一个跨越两个显示器的窗口,我似乎无法擦除(涂黑)整个窗口。相反,只有主窗口会被涂成黑色,次要窗口仍然保持原来的白色。有人遇到过这种情况吗?
wxWidgets:
在dc.Clear()函数内部,有以下代码:
wxWidgets:
wxClientDC dc(this);
Erase(dc);
void SpriteWindowFrame::Erase(wxDC& dc)
{
dc.SetBackground(*wxBLACK_BRUSH);
dc.SetBrush(*wxBLACK_BRUSH);
dc.Clear();
//wxLogDebug("Erase called. Rect is %i, %i w:%i, h:%i", GetPosition().x, GetPosition().y, GetSize().GetWidth(), GetSize().GetHeight());
}
在dc.Clear()函数内部,有以下代码:
void wxDC::Clear()
{
WXMICROWIN_CHECK_HDC
RECT rect;
if ( m_canvas )
{
GetClientRect((HWND) m_canvas->GetHWND(), &rect);
}
else
{
// No, I think we should simply ignore this if printing on e.g.
// a printer DC.
// wxCHECK_RET( m_selectedBitmap.Ok(), wxT("this DC can't be cleared") );
if (!m_selectedBitmap.Ok())
return;
rect.left = -m_deviceOriginX; rect.top = -m_deviceOriginY;
rect.right = m_selectedBitmap.GetWidth()-m_deviceOriginX;
rect.bottom = m_selectedBitmap.GetHeight()-m_deviceOriginY;
}
#ifndef __WXWINCE__
(void) ::SetMapMode(GetHdc(), MM_TEXT);
#endif
DWORD colour = ::GetBkColor(GetHdc());
HBRUSH brush = ::CreateSolidBrush(colour);
::FillRect(GetHdc(), &rect, brush);
::DeleteObject(brush);
#ifndef __WXWINCE__
int width = DeviceToLogicalXRel(VIEWPORT_EXTENT)*m_signX,
height = DeviceToLogicalYRel(VIEWPORT_EXTENT)*m_signY;
::SetMapMode(GetHdc(), MM_ANISOTROPIC);
::SetViewportExtEx(GetHdc(), VIEWPORT_EXTENT, VIEWPORT_EXTENT, NULL);
::SetWindowExtEx(GetHdc(), width, height, NULL);
::SetViewportOrgEx(GetHdc(), (int)m_deviceOriginX, (int)m_deviceOriginY, NULL);
::SetWindowOrgEx(GetHdc(), (int)m_logicalOriginX, (int)m_logicalOriginY, NULL);
#endif
使用调试器,我检查了GetClientRect返回的内容,它确实返回了一个位置为0、宽度/高度为两个显示器组合的矩形,所以是正确的。可能fillrect函数无法绘制到两个显示器上?