C++ QTextLayout::font方法代码示例

void YTDelegate::layoutText(QTextLayout& textLayout, QString text, QSize constraint) const
{
    QTextOption textOption(Qt::AlignJustify);
    textLayout.setTextOption(textOption);
    textLayout.setText(text);
    textLayout.beginLayout();
    int lHeight = 0;
    while(true){
        QTextLine line = textLayout.createLine();
        if(!line.isValid())
            break;
        line.setLineWidth(constraint.width());
        line.setPosition(QPointF(0, lHeight));
        if(lHeight + line.height() > constraint.height())
        {
            QTextLine lastLine = textLayout.lineAt(textLayout.lineCount() - 2);
            QString lastString = text.mid(lastLine.textStart());
            QFontMetrics fm(textLayout.font());
            text.chop(lastString.length());
            text += fm.elidedText(lastString, Qt::ElideRight, constraint.width()-1);
            textLayout.endLayout();
            layoutText(textLayout, text, constraint);
            return;
        }
        lHeight += line.height();
        lHeight += line.leading();
    }
    textLayout.endLayout();
}

void TextLabel::layoutText(QTextLayout &layout, const QString &text, const QSize &constraints)
{
    QFontMetrics metrics(layout.font());
    int leading = metrics.leading();
    int height = 0;
    int maxWidth = constraints.width();
    int widthUsed = 0;
    int lineSpacing = metrics.lineSpacing();
    QTextLine line;

    layout.setText(text);

    layout.beginLayout();
    while ((line = layout.createLine()).isValid()) {
        height += leading;

        // Make the last line that will fit infinitely long.
        // drawTextLayout() will handle this by fading the line out
        // if it won't fit in the constraints.
        if (height + 2 * lineSpacing > constraints.height()) {
            line.setPosition(QPoint(0, height));
            break;
        }

        line.setLineWidth(maxWidth);
        line.setPosition(QPoint(0, height));

        height += int(line.height());
        widthUsed = int(qMax(qreal(widthUsed), line.naturalTextWidth()));
    }
    layout.endLayout();
}

void TextLabel::drawTextLayout(QPainter *painter, const QTextLayout &layout, const QRect &rect)
{
    if (rect.width() < 1 || rect.height() < 1) {
        return;
    }

    QPixmap pixmap(rect.size());
    pixmap.fill(Qt::transparent);

    QPainter p(&pixmap);
    p.setPen(painter->pen());

    // Create the alpha gradient for the fade out effect
    QLinearGradient alphaGradient(0, 0, 1, 0);
    alphaGradient.setCoordinateMode(QGradient::ObjectBoundingMode);
    if (layout.textOption().textDirection() == Qt::LeftToRight) {
        alphaGradient.setColorAt(0, QColor(0, 0, 0, 255));
        alphaGradient.setColorAt(1, QColor(0, 0, 0, 0));
    } else {
        alphaGradient.setColorAt(0, QColor(0, 0, 0, 0));
        alphaGradient.setColorAt(1, QColor(0, 0, 0, 255));
    }

    QFontMetrics fm(layout.font());
    int textHeight = layout.lineCount() * fm.lineSpacing();

    QPointF position(0, (rect.height() - textHeight) / 2);
    QList<QRect> fadeRects;
    int fadeWidth = 30;

    // Draw each line in the layout
    for (int i = 0; i < layout.lineCount(); i++) {
        QTextLine line = layout.lineAt(i);
        line.draw(&p, position);

        // Add a fade out rect to the list if the line is too long
        if (line.naturalTextWidth() > rect.width())
        {
            int x = int(qMin(line.naturalTextWidth(), (qreal)pixmap.width())) - fadeWidth;
            int y = int(line.position().y() + position.y());
            QRect r = QStyle::visualRect(layout.textOption().textDirection(), pixmap.rect(),
                                         QRect(x, y, fadeWidth, int(line.height())));
            fadeRects.append(r);
        }
    }

    // Reduce the alpha in each fade out rect using the alpha gradient
    if (!fadeRects.isEmpty()) {
        p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
        foreach (const QRect &rect, fadeRects) {
            p.fillRect(rect, alphaGradient);
        }

void DTPatientListDelegate::drawHightlightText(QPainter *painter,
                                               QString text,
                                               QString substring,
                                               QRect pos,
                                               Qt::CaseSensitivity cs,
                                               bool boldFont,
                                               QColor highlight) const
{
    if (!painter || (text.length() == 0))
        return;

    painter->save();
    QVector<QTextLayout::FormatRange> selections;
    QTextLayout textLayout;
    textLayout.setText(text);

    if (substring.length() != 0)
    {
        int idx = -1;
        int start = 0;
        while (1)
        {
            idx = text.indexOf(substring, start,cs);
            if (idx == -1)
                break;

            QTextLayout::FormatRange* range = new QTextLayout::FormatRange;
            range->start = idx;
            range->length = substring.length();
            range->format.setBackground(QBrush(QColor(highlight)));
            selections.append(*range);
            start += substring.length();
        }
    }

    if (boldFont)
    {
        QFont f = textLayout.font();
        f.setBold(true);
        textLayout.setFont(f);
    }

    int leading = painter->fontMetrics().leading();
    qreal height = 0;
    textLayout.beginLayout();
    while (1) {
        QTextLine line = textLayout.createLine();
        if (!line.isValid())
            break;

        line.setLineWidth(pos.width());
        height += leading;
        line.setPosition(QPointF(0, height));
        height += line.height();
    }
    textLayout.endLayout();

    textLayout.draw(painter, pos.topLeft(), selections);

    painter->restore();

}