XReparentWindow踩坑分析

        X11是Linux发行系统中广泛采用的显示协议，各个系统基本上都支持XLib库，作为底层接口，XReparentWindow接口的功能就是重新设置父窗口，注意这个可以跨进程设置父窗口，例如将已经运行的进程的父窗口设置自己的程序Wid，即可将第三方进程嵌入到自己的程序窗口中，自己用这个接口写了一段代码，在UOS上运行的正常，后面跑在Kylin 4.0.2和V10上，程序出现了一些难以琢磨的情况，嵌入的程序无法focus，查阅到qt的container容器可以完成这个功能，查阅了qt4和qt5的源码，发先程序嵌入确实不是简简单单的XReparentWindow调用，后续还涉及到各种消息转发操作，后续学习。

bool QX11EmbedContainer::eventFilter(QObject *o, QEvent *event)
{Q_D(QX11EmbedContainer);switch (event->type()) {case QEvent::KeyPress:// Forward any keypresses to our client.if (o == this && d->client) {lastKeyEvent.window = d->client;XSendEvent(x11Info().display(), d->client, false, KeyPressMask, (XEvent *) &lastKeyEvent);return true;}break;case QEvent::KeyRelease:// Forward any keyreleases to our client.if (o == this && d->client) {lastKeyEvent.window = d->client;XSendEvent(x11Info().display(), d->client, false, KeyReleaseMask, (XEvent *) &lastKeyEvent);return true;}break;case QEvent::WindowActivate:// When our container window is activated, we pass the// activation message on to our client. Note that X input// focus is set to our focus proxy. We want to intercept all// keypresses.if (o == window() && d->client) {if (d->clientIsXEmbed) {sendXEmbedMessage(d->client, x11Info().display(), XEMBED_WINDOW_ACTIVATE);} else {d->checkGrab();if (hasFocus())XSetInputFocus(x11Info().display(), d->client, XRevertToParent, x11Time());}if (!d->isEmbedded())d->moveInputToProxy();}break;case QEvent::WindowDeactivate:// When our container window is deactivated, we pass the// deactivation message to our client.if (o == window() && d->client) {if (d->clientIsXEmbed)sendXEmbedMessage(d->client, x11Info().display(), XEMBED_WINDOW_DEACTIVATE);elsed->checkGrab();}break;case QEvent::FocusIn:// When receiving FocusIn events generated by Tab or Backtab,// we pass focus on to our client. Any mouse activity is sent// directly to the client, and it will ask us for focus with// XEMBED_REQUEST_FOCUS.if (o == this && d->client) {if (!d->isEmbedded())d->activeContainer = this;if (d->clientIsXEmbed) {if (!d->isEmbedded())d->moveInputToProxy();QFocusEvent *fe = (QFocusEvent *)event;switch (fe->reason()) {case Qt::TabFocusReason:sendXEmbedMessage(d->client, x11Info().display(), XEMBED_FOCUS_IN, XEMBED_FOCUS_FIRST);break;case Qt::BacktabFocusReason:sendXEmbedMessage(d->client, x11Info().display(), XEMBED_FOCUS_IN, XEMBED_FOCUS_LAST);break;default:sendXEmbedMessage(d->client, x11Info().display(), XEMBED_FOCUS_IN, XEMBED_FOCUS_CURRENT);break;}} else {d->checkGrab();XSetInputFocus(x11Info().display(), d->client, XRevertToParent, x11Time());}}break;case QEvent::FocusOut: {// When receiving a FocusOut, we ask our client to remove its// focus.if (o == this && d->client) {if (!d->isEmbedded()) {d->activeContainer = 0;if (isActiveWindow())d->moveInputToProxy();}if (d->clientIsXEmbed) {QFocusEvent *fe = (QFocusEvent *)event;if (o == this && d->client && fe->reason() != Qt::ActiveWindowFocusReason)sendXEmbedMessage(d->client, x11Info().display(), XEMBED_FOCUS_OUT);} else {d->checkGrab();}}}break;case QEvent::Close: {if (o == this && d->client) {// Unmap the client and reparent it to the root window.// Wait until the messages have been processed. Then ask// the window manager to delete the window.XUnmapWindow(x11Info().display(), d->client);XReparentWindow(x11Info().display(), d->client, x11Info().appRootWindow(x11Info().screen()), 0, 0);XSync(x11Info().display(), false);XEvent ev;memset(&ev, 0, sizeof(ev));ev.xclient.type = ClientMessage;ev.xclient.window = d->client;ev.xclient.message_type = ATOM(WM_PROTOCOLS);ev.xclient.format = 32;ev.xclient.data.s[0] = ATOM(WM_DELETE_WINDOW);XSendEvent(x11Info().display(), d->client, false, NoEventMask, &ev);XFlush(x11Info().display());d->client = 0;d->clientIsXEmbed = false;d->wmMinimumSizeHint = QSize();updateGeometry();setEnabled(false);update();emit clientClosed();}}default:break;}return QWidget::eventFilter(o, event);
}

        麒麟系统和WPS软件，qt4的QXEmbedContainer和qt5 createContainer嵌入wps时显示空白，慢慢研究解决方案去。