qt 自定義不規則窗體與按鈕

           設置不規則的窗體，主要使用 QRegion 類定義可見區域，並通過setMask 函數實現，如下爲qt 自帶的實例搜索

Shaped Clock Example 即可找到。

ShapedClock::ShapedClock(QWidget *parent)
    : QWidget(parent, Qt::FramelessWindowHint | Qt::WindowSystemMenuHint)
{
    //Qt::FramelessWindowHint 設置無邊框
    // Qt::WindowSystemMenuHint  WindowCloseButtonHint 兩個功能相似，添加一個系統按鈕
    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
    timer->start(1000);

    //添加菜單動作（功能）
    QAction *quitAction = new QAction(tr("E&xit"), this);
    quitAction->setShortcut(tr("Ctrl+Q"));
    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
    addAction(quitAction);

    //設置顯示規則，顯示QWidget::actions() 的菜單
    setContextMenuPolicy(Qt::ActionsContextMenu);
    //設置窗口提示
    setToolTip(tr("Drag the clock with the left mouse button.\n"
                  "Use the right mouse button to open a context menu."));
    //設置窗口主題
    setWindowTitle(tr("Shaped Analog Clock"));
}
//! [0]

//! [1]
// 設置無邊框後，窗體無法實現按住鼠標右鍵移動，需要自己繼承
// mousePressEvent  mouseMoveEvent 實現
void ShapedClock::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton) {
        dragPosition = event->globalPos() - frameGeometry().topLeft();
        event->accept();
    }
}
//! [1]

//! [2]
void ShapedClock::mouseMoveEvent(QMouseEvent *event)
{
    if (event->buttons() & Qt::LeftButton) {
        move(event->globalPos() - dragPosition);
        event->accept();
    }
}
//! [2]

//! [3]
void ShapedClock::paintEvent(QPaintEvent *)
{
    static const QPoint hourHand[3] = {
        QPoint(7, 8),
        QPoint(-7, 8),
        QPoint(0, -40)
    };
    static const QPoint minuteHand[3] = {
        QPoint(7, 8),
        QPoint(-7, 8),
        QPoint(0, -70)
    };

    QColor hourColor(127, 0, 127);
    QColor minuteColor(0, 127, 127, 191);

    int side = qMin(width(), height());
    QTime time = QTime::currentTime();

    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing); //設置抗鋸齒
    painter.translate(width() / 2, height() / 2);
    painter.scale(side / 200.0, side / 200.0);

    painter.setPen(Qt::NoPen);
    painter.setBrush(hourColor);

    painter.save();
    painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
    painter.drawConvexPolygon(hourHand, 3);
    painter.restore();

    painter.setPen(hourColor);

    for (int i = 0; i < 12; ++i) {
        painter.drawLine(88, 0, 96, 0);
        painter.rotate(30.0);
    }

    painter.setPen(Qt::NoPen);
    painter.setBrush(minuteColor);

    painter.save();
    painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
    painter.drawConvexPolygon(minuteHand, 3);
    painter.restore();

    painter.setPen(minuteColor);

    for (int j = 0; j < 60; ++j) {
        if ((j % 5) != 0)
            painter.drawLine(92, 0, 96, 0);
        painter.rotate(6.0);
    }
}
//! [3]

//! [4]
void ShapedClock::resizeEvent(QResizeEvent * /* event */)
{
    int side = qMin(width(), height());
    //定義需要可見的區域
    QRegion maskedRegion(width() / 2 - side / 2, height() / 2 - side / 2, side,
                         side, QRegion::Ellipse);
    // 通過setMask設置可見的區域
    setMask(maskedRegion);
}
//! [4]

//! [5]
QSize ShapedClock::sizeHint() const
{
    // 設置默認大小
    return QSize(100, 100);
}
//! [5]