按钮绘制不同步

[nmgwddj]

Discussed in #381

^{Originally posted by huangzhengyi February 10, 2022}
设置按钮的normal(红)、hot(绿) 2种状态颜色

<Button name="btn_test" width="200" height="200" normalcolor="#ffff0000" hotcolor="#ff00ff00"/>

加入按钮点击处理函数

m_pButton->AttachClick([this](ui::EventArgs* args) {
	SendMessage(WM_SYSCOMMAND, SC_MINIMIZE, 0); 
	return true;
});

会出现，当我们点击按钮窗口最小化了，但是我们重新点击任务栏的窗口显示窗口，发现按钮还是绿色，只有鼠标放在窗口或者按钮上才会重绘这个窗口

void Window::Invalidate(const UiRect& rcItem)
{
::InvalidateRect(m_hWnd, &rcItem, FALSE);
// Invalidating a layered window will not trigger a WM_PAINT message,
// thus we have to post WM_PAINT by ourselves.
if (m_bIsLayeredWindow) {
	::PostMessage(m_hWnd, WM_PAINT, (LPARAM)&rcItem, (WPARAM)FALSE);
}
}

void Window::Paint()
{
if (::IsIconic(m_hWnd) || !m_pRoot) {
	PAINTSTRUCT ps = { 0 };
	::BeginPaint(m_hWnd, &ps);
	::EndPaint(m_hWnd, &ps);
	return;
}
....

发现，是通过post发送的paint消息，怀疑是当我点击按钮之后，窗口隐藏了之后才收到paint导致的

[huangzhengyi]

((Button*)msg->pSender)->SetState(kControlStateNormal);
ui::UiRect _rcWnd;
::SendMessage(m_hWnd, WM_PAINT, (LPARAM)&_rcWnd, (WPARAM)FALSE);
ShowWindow(false);

在按钮隐藏前，先刷新一遍