如何在Qt中使项目视图呈现丰富（html）文本

问题描述 投票：46回答：4

假设我的模型具有Qt :: DisplayRole的以下字符串的项目

<span>blah-blah <b>some text</b> other blah</span>

我想要QTreeView（实际上，任何项目视图）将其渲染为富文本。相反，项目视图默认情况下将其呈现为纯文本。如何实现所需的渲染？

实际上，这是一个搜索结果模型。用户输入文本，根据该文本搜索某些文档，并向用户显示搜索结果，其中搜索的单词应比周围文本更大胆。

qt rendering richtext qtreeview qlistview
4个回答
36
投票

我想你可以使用treeview的setItemDelegate方法为你的treeview项目设置自定义画家。在委托的paint方法中，您可以使用QTextDocument将项目的文本加载为html并进行渲染。请检查以下示例是否适合您：

treeview初始化：

...
    // create simple model for a tree view
    QStandardItemModel *model = new QStandardItemModel();
    QModelIndex parentItem;
    for (int i = 0; i < 4; ++i)
    {
        parentItem = model->index(0, 0, parentItem);
        model->insertRows(0, 1, parentItem);
        model->insertColumns(0, 1, parentItem);
        QModelIndex index = model->index(0, 0, parentItem);
        model->setData(index, "<span>blah-blah <b>some text</b> other blah</span>");
    }
    // create custom delegate
    HTMLDelegate* delegate = new HTMLDelegate();
    // set model and delegate to the treeview object
    ui->treeView->setModel(model);
    ui->treeView->setItemDelegate(delegate);
...

自定义委托实现

class HTMLDelegate : public QStyledItemDelegate
{
protected:
    void paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const;
    QSize sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const;
};

void HTMLDelegate::paint(QPainter* painter, const QStyleOptionViewItem & option, const QModelIndex &index) const
{
    QStyleOptionViewItemV4 options = option;
    initStyleOption(&options, index);

    painter->save();

    QTextDocument doc;
    doc.setHtml(options.text);

    options.text = "";
    options.widget->style()->drawControl(QStyle::CE_ItemViewItem, &options, painter);

    painter->translate(options.rect.left(), options.rect.top());
    QRect clip(0, 0, options.rect.width(), options.rect.height());
    doc.drawContents(painter, clip);

    painter->restore();
}

QSize HTMLDelegate::sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
    QStyleOptionViewItemV4 options = option;
    initStyleOption(&options, index);

    QTextDocument doc;
    doc.setHtml(options.text);
    doc.setTextWidth(options.rect.width());
    return QSize(doc.idealWidth(), doc.size().height());
}

希望这有帮助，问候

update0：对HTMLDelegate的更改，使图标可见，所选项目的笔颜色也不同

void HTMLDelegate::paint(QPainter* painter, const QStyleOptionViewItem & option, const QModelIndex &index) const
{
    QStyleOptionViewItemV4 options = option;
    initStyleOption(&options, index);

    painter->save();

    QTextDocument doc;
    doc.setHtml(options.text);

    options.text = "";
    options.widget->style()->drawControl(QStyle::CE_ItemViewItem, &options, painter);

    // shift text right to make icon visible
    QSize iconSize = options.icon.actualSize(options.rect.size());
    painter->translate(options.rect.left()+iconSize.width(), options.rect.top());
    QRect clip(0, 0, options.rect.width()+iconSize.width(), options.rect.height());

    //doc.drawContents(painter, clip);

    painter->setClipRect(clip);
    QAbstractTextDocumentLayout::PaintContext ctx;
    // set text color to red for selected item
    if (option.state & QStyle::State_Selected)
        ctx.palette.setColor(QPalette::Text, QColor("red"));
    ctx.clip = clip;
    doc.documentLayout()->draw(painter, ctx);

    painter->restore();
}
20
投票

我的答案主要是受@ serge_gubenko的启发。但是，有一些改进，以便代码最终在我的应用程序中有用。

class HtmlDelegate : public QStyledItemDelegate
{
protected:
    void paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const;
    QSize sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const;
};

void HtmlDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QStyleOptionViewItemV4 optionV4 = option;
    initStyleOption(&optionV4, index);

    QStyle *style = optionV4.widget? optionV4.widget->style() : QApplication::style();

    QTextDocument doc;
    doc.setHtml(optionV4.text);

    /// Painting item without text
    optionV4.text = QString();
    style->drawControl(QStyle::CE_ItemViewItem, &optionV4, painter);

    QAbstractTextDocumentLayout::PaintContext ctx;

    // Highlighting text if item is selected
    if (optionV4.state & QStyle::State_Selected)
        ctx.palette.setColor(QPalette::Text, optionV4.palette.color(QPalette::Active, QPalette::HighlightedText));

    QRect textRect = style->subElementRect(QStyle::SE_ItemViewItemText, &optionV4);
    painter->save();
    painter->translate(textRect.topLeft());
    painter->setClipRect(textRect.translated(-textRect.topLeft()));
    doc.documentLayout()->draw(painter, ctx);
    painter->restore();
}

QSize HtmlDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QStyleOptionViewItemV4 optionV4 = option;
    initStyleOption(&optionV4, index);

    QTextDocument doc;
    doc.setHtml(optionV4.text);
    doc.setTextWidth(optionV4.rect.width());
    return QSize(doc.idealWidth(), doc.size().height());
}
15
投票

以下是对我有用的上述答案组合的PyQt转换。我希望这对PySide几乎完全相同。

from PyQt4 import QtCore, QtGui

class HTMLDelegate(QtGui.QStyledItemDelegate):
    def paint(self, painter, option, index):
        options = QtGui.QStyleOptionViewItemV4(option)
        self.initStyleOption(options,index)

        style = QtGui.QApplication.style() if options.widget is None else options.widget.style()

        doc = QtGui.QTextDocument()
        doc.setHtml(options.text)

        options.text = ""
        style.drawControl(QtGui.QStyle.CE_ItemViewItem, options, painter);

        ctx = QtGui.QAbstractTextDocumentLayout.PaintContext()

        # Highlighting text if item is selected
        #if (optionV4.state & QStyle::State_Selected)
            #ctx.palette.setColor(QPalette::Text, optionV4.palette.color(QPalette::Active, QPalette::HighlightedText));

        textRect = style.subElementRect(QtGui.QStyle.SE_ItemViewItemText, options)
        painter.save()
        painter.translate(textRect.topLeft())
        painter.setClipRect(textRect.translated(-textRect.topLeft()))
        doc.documentLayout().draw(painter, ctx)

        painter.restore()

    def sizeHint(self, option, index):
        options = QtGui.QStyleOptionViewItemV4(option)
        self.initStyleOption(options,index)

        doc = QtGui.QTextDocument()
        doc.setHtml(options.text)
        doc.setTextWidth(options.rect.width())
        return QtCore.QSize(doc.idealWidth(), doc.size().height())
5
投票

这个是在PySide。我没有做很多自定义绘图，而是将QPainter传递给QLabel并使其自行绘制。突出显示从其他答案借来的代码。

from PySide import QtGui

class TaskDelegate(QtGui.QItemDelegate):
    #https://doc.qt.io/archives/qt-4.7/qitemdelegate.html#drawDisplay
    #https://doc.qt.io/archives/qt-4.7/qwidget.html#render
    def drawDisplay(self, painter, option, rect, text):
        label = QtGui.QLabel(text)

        if option.state & QtGui.QStyle.State_Selected:
            p = option.palette
            p.setColor(QtGui.QPalette.WindowText, p.color(QtGui.QPalette.Active, QtGui.QPalette.HighlightedText))

            label.setPalette(p)

        label.render(painter, rect.topLeft(), renderFlags=QtGui.QWidget.DrawChildren)
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