如何使项目视图在Qt中呈现丰富的(html)文本?

Suppose my model has items with the following string for Qt::DisplayRole

假设我的模型有以下字符串，用于Qt::DisplayRole。

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

I want QTreeView (actually, any item view) to render it like a rich text. Instead, item views render it like a pure text by default. How to achieve the desired rendering?

我想要QTreeView(实际上，任何项目视图)来呈现它像一个富文本。相反，在默认情况下，项视图将其呈现为纯文本。如何实现所需的渲染?

---

Actually, this is a search results model. User enters a text, some document is searched against that text and the user is presented with search results, where the words being searched should be bolder than surrounding text.

实际上，这是一个搜索结果模型。用户输入文本，对该文本进行搜索，并向用户显示搜索结果，在搜索结果中搜索的单词应该比周围的文本更醒目。

4 个解决方案

#1

I guess you can use setItemDelegate method of the treeview to setup custom painter for your treeview items. In the delegate's paint method you can use QTextDocument to load item's text as html and render it. Please check if an example below would work for you:

我猜您可以使用treeview的setItemDelegate方法来为treeview项设置定制的油漆工。在委托的paint方法中，可以使用QTextDocument将项目的文本加载为html并呈现。请检查下面的例子是否适合你:

treeview initialization:

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);
...

custom delegate implementation

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());
}

hope this helps, regards

希望这有助于,问候

update0: changes to HTMLDelegate to make icons visible and different pen color for selected items

update0:对HTMLDelegate进行更改，以使选定项的图标可见和不同的钢笔颜色。

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();
}

#2

My answer is mostly inspired by @serge_gubenko's one. However, there were made several improvements so that the code is finally useful in my application.

我的回答主要是受@serge_gubenko的启发。但是，有一些改进，使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());
}

#3

Here's the PyQt conversion of the combination of the above answers that worked for me. I would expect this to work virtually identically for PySide as well.

这里是PyQt转换，上面的答案对我有用。我希望这对PySide也一样。

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())

#4

This one is in PySide. Rather than doing a lot of custom drawing, I pass the QPainter to the QLabel and make it draw itself. Highlighting code borrowed from other answers.

这个在PySide。我没有做大量的自定义绘图，而是将QPainter传递给了QLabel并使它自己绘制。突出显示从其他答案中借用的代码。

from PySide import QtGui

class TaskDelegate(QtGui.QItemDelegate):
    #http://doc.qt.nokia.com/4.7/qitemdelegate.html#drawDisplay
    #http://doc.qt.nokia.com/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)