Qt 设置小部件的文本方向

Question

我想更改表格小部件垂直标题的文本方向。我打算将其从默认的水平更改为垂直。从下到上。

Answer 1

在表格标题中显示垂直文本

很遗憾，QHeaderViewdoes not support custom delegates。但是，我们可以继承 QHeaderView 并覆盖 paintSection 和 sectionSizeFromContents 并在那里垂直绘制文本。请注意，我们可以重用相同的基本实现，在渲染时考虑各种因素（例如，如果鼠标指针在标题上，如果用户正在单击标题，...）并免费获得所有这些考虑因素。以下是我将如何实现这样一个类：

//a header view that renders text vertically
class VerticalHeaderView : public QHeaderView {
public:
    explicit VerticalHeaderView(Qt::Orientation orientation, QWidget *parent = nullptr)
        : QHeaderView(orientation, parent) {}

    void paintSection(QPainter *painter, const QRect &rect,
                      int logicalIndex) const override {
        QPointF rectCenter = QRectF(rect).center();
        painter->save();
        //rotate around rectCenter
        painter->translate(rectCenter.x(), rectCenter.y());
        painter->rotate(-90.0);
        painter->translate(-rectCenter.x(), -rectCenter.y());
        //apply the same transformation on the rect
        QRect rectCopy = painter->worldTransform().mapRect(rect);
        //use base paintSection method after applying required transformations
        QHeaderView::paintSection(painter, rectCopy, logicalIndex);
        painter->restore();
    }

    QSize sectionSizeFromContents(int logicalIndex) const override {
        //get sizeHint from base sizeHint method
        QSize val = QHeaderView::sectionSizeFromContents(logicalIndex);
        //swap height and width
        return QSize(val.height(), val.width());
    }
};

要使用上面的类，我们需要在我们的QTableView/QTableWidget 上使用setVerticalHeader() 设置它（它也可以用作表格的水平标题，但这在大多数情况下没有意义例）。下面是一个完整的例子，展示了上述类的作用：

#include <QtWidgets>

//a header view that renders text vertically
class VerticalHeaderView : public QHeaderView {
public:
    explicit VerticalHeaderView(Qt::Orientation orientation, QWidget *parent = nullptr)
        : QHeaderView(orientation, parent) {}

    void paintSection(QPainter *painter, const QRect &rect,
                      int logicalIndex) const override {
        QPointF rectCenter = QRectF(rect).center();
        painter->save();
        //rotate around rectCenter
        painter->translate(rectCenter.x(), rectCenter.y());
        painter->rotate(-90.0);
        painter->translate(-rectCenter.x(), -rectCenter.y());
        //apply the same transformation on the rect
        QRect rectCopy = painter->worldTransform().mapRect(rect);
        //use base paintSection method after applying required transformations
        QHeaderView::paintSection(painter, rectCopy, logicalIndex);
        painter->restore();
    }

    QSize sectionSizeFromContents(int logicalIndex) const override {
        //get sizeHint from base sizeHint method
        QSize val = QHeaderView::sectionSizeFromContents(logicalIndex);
        //swap height and width
        return QSize(val.height(), val.width());
    }
};

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    //setup model with dummy data
    QStandardItemModel model(0, 1);
    for(int i=0; i<5; i++) {
        model.appendRow(new QStandardItem(QStringLiteral("Lorem ipsum dolor sit "
                        "amet, consectetur adipiscing elit, sed do eiusmod tempor "
                        "incididunt ut labore et dolore magna aliqua. Ut enim ad "
                        "minim veniam, quis nostrud exercitation ullamco laboris "
                        "nisi ut aliquip ex ea commodo consequat.")));
        model.setHeaderData(i, Qt::Vertical,
                            QDate::currentDate().toString("dd-MM-yyyy"),
                            Qt::DisplayRole);
        model.setHeaderData(i, Qt::Vertical, Qt::AlignCenter, Qt::TextAlignmentRole);
    }

    //setup view
    QTableView view;
    VerticalHeaderView headerView(Qt::Vertical);
    view.setVerticalHeader(&headerView); //set our custom headerview
    view.verticalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
    view.setModel(&model);
    view.show();

    return a.exec();
}

在表格单元格中显示竖排文本^*

您可以编写一个垂直呈现文本的delegate class。您需要覆盖 paint 和 sizeHint 并在那里提供您的代码。在应用所需的转换后，也可以重用相同的基本实现。以下是我将如何实现这样一个类：

//a delegate that renders text vertically
class VerticalTextDelegate : public QStyledItemDelegate {
public:
    explicit VerticalTextDelegate(QObject *parent = nullptr)
        : QStyledItemDelegate(parent){}
    virtual void paint(QPainter *painter, const QStyleOptionViewItem &option,
                       const QModelIndex &index) const override {
        QStyleOptionViewItem optionCopy = option;
        QPointF rectCenter = QRectF(option.rect).center();
        painter->save();
        //rotate around rectCenter
        painter->translate(rectCenter.x(), rectCenter.y());
        painter->rotate(-90.0);
        painter->translate(-rectCenter.x(), -rectCenter.y());
        //apply the same transformation on the rect
        optionCopy.rect = painter->worldTransform().mapRect(option.rect);
        //use base paint method after applying required transformations
        QStyledItemDelegate::paint(painter, optionCopy, index);
        painter->restore();
    }

    virtual QSize sizeHint(const QStyleOptionViewItem &option,
                           const QModelIndex &index) const override {
        //get sizeHint from base sizeHint method
        QSize val = QStyledItemDelegate::sizeHint(option, index);
        //swap height and width
        return QSize(val.height(), val.width());
    }
};

这是一个使用上述类的完整示例：

#include <QtWidgets>

//a delegate that renders text vertically
class VerticalTextDelegate : public QStyledItemDelegate {
public:
    explicit VerticalTextDelegate(QObject *parent = nullptr)
        : QStyledItemDelegate(parent){}
    virtual void paint(QPainter *painter, const QStyleOptionViewItem &option,
                       const QModelIndex &index) const override {
        QStyleOptionViewItem optionCopy = option;
        QPointF rectCenter = QRectF(option.rect).center();
        painter->save();
        //rotate around rectCenter
        painter->translate(rectCenter.x(), rectCenter.y());
        painter->rotate(-90.0);
        painter->translate(-rectCenter.x(), -rectCenter.y());
        //apply the same transformation on the rect
        optionCopy.rect = painter->worldTransform().mapRect(option.rect);
        //use base paint method after applying required transformations
        QStyledItemDelegate::paint(painter, optionCopy, index);
        painter->restore();
    }

    virtual QSize sizeHint(const QStyleOptionViewItem &option,
                           const QModelIndex &index) const override {
        //get sizeHint from base sizeHint method
        QSize val = QStyledItemDelegate::sizeHint(option, index);
        //swap height and width
        return QSize(val.height(), val.width());
    }
};

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    //setup model with dummy data
    QStandardItemModel model(0, 2);
    for(int i=0; i<5; i++) {
        model.appendRow({new QStandardItem(QDate::currentDate().toString("dd-MM-yyyy")),
                         new QStandardItem(QStringLiteral("Lorem ipsum dolor sit "
                         "amet, consectetur adipiscing elit, sed do eiusmod tempor "
                         "incididunt ut labore et dolore magna aliqua. Ut enim ad "
                         "minim veniam, quis nostrud exercitation ullamco laboris "
                         "nisi ut aliquip ex ea commodo consequat."))});
        model.setData(model.index(i, 0), Qt::AlignCenter, Qt::TextAlignmentRole);
    }

    //setup view and delegate
    QTableView view;
    VerticalTextDelegate delegate;
    view.verticalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
    view.setItemDelegateForColumn(0, &delegate);
    view.setModel(&model);
    view.show();

    return a.exec();
}

---

^{显然，当我第一次回答这个问题时，我误解了这个问题，但我将把它作为一个单独的部分，因为它可能对未来的读者有用。}