1.如何求指定宽度的文本的高度

paintEvent(QPaintEvent *event)
{QPainter painter(this);QString text = "Invalid parameter passed to C runtime function.";QFontMetrics fm(qApp->font());QTextDocument doc(text);doc.setDefaultFont(painter.font());doc.setTextWidth(100);doc.adjustSize();painter.fillRect(QRect(QPoint(0, 0), doc.size().toSize()), Qt::yellow);doc.drawContents(&painter);
}

更新方法

QFontMetrics(font).boundingRect(QRect(0, 0, option.rect.width(), 0), Qt::AlignCenter|Qt::TextWordWrap, text);

2.ubuntu下ping ipv6

服务端

    QTcpServer *server = new QTcpServer(this);server->listen(QHostAddress("FE80::AF72:573C:4B61:CABD%eno1"), 8080);connect(server, &QTcpServer::newConnection, this, [=](){qDebug() << "new connection" << server->nextPendingConnection()->peerAddress();});

客户端

 QTcpSocket tcp;tcp.connectToHost(QHostAddress("FE80::AF72:573C:4B61:CABD%eno1"), 8080);tcp.waitForConnected();

终端ping

XXX@YYY:~/桌面$ ping6 fe80::af72:573c:4b61:cabd%eno1 PING fe80::af72:573c:4b61:cabd%eno1(fe80::af72:573c:4b61:cabd%eno1) 56 data bytes 64 bytes from fe80::af72:573c:4b61:cabd%eno1: icmp_seq=1 ttl=64 time=0.027 ms 64 bytes from fe80::af72:573c:4b61:cabd%eno1: icmp_seq=2 ttl=64 time=0.022 ms 64 bytes from fe80::af72:573c:4b61:cabd%eno1: icmp_seq=3 ttl=64 time=0.031 ms 64 bytes from fe80::af72:573c:4b61:cabd%eno1: icmp_seq=4 ttl=64 time=0.035 ms 64 bytes from fe80::af72:573c:4b61:cabd%eno1: icmp_seq=5 ttl=64 time=0.041 ms ^C --- fe80::af72:573c:4b61:cabd%eno1 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4102ms rtt min/avg/max/mdev = 0.022/0.031/0.041/0.006 ms

3.Ubuntu下git提示：终止提交因为提交说明为空

这么简单的问题居然搜索了一会儿，现在的网络环境越来越差了。

解决方法：

gedit:

git config --global core.editor "gedit -s"

the paramater "-s " means set the gedit mode to "standalone"

Sublime Text 2

git config --global core.editor "subl -w"

the paramater "-w" means return until the file was closed.

参考：https://www.cnblogs.com/maadiah/archive/2012/02/27/2369931.html