C++ QTextLayout::beginLayout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();
}

// Origin: Qt
static void viewItemTextLayout ( QTextLayout &textLayout, int lineWidth, qreal &height, qreal &widthUsed )
{
	height = 0;
	widthUsed = 0;
	textLayout.beginLayout();
	while ( true )
	{
		QTextLine line = textLayout.createLine();
		if ( !line.isValid() )
			break;
		line.setLineWidth ( lineWidth );
		line.setPosition ( QPointF ( 0, height ) );
		height += line.height();
		widthUsed = qMax ( widthUsed, line.naturalTextWidth() );
	}
	textLayout.endLayout();
}

void tst_QRawFont::unsupportedWritingSystem()
{
    QFETCH(QFont::HintingPreference, hintingPreference);

    QFontDatabase fontDatabase;
    int id = fontDatabase.addApplicationFont(QLatin1String(SRCDIR "testfont.ttf"));

    QFont font("QtBidiTestFont");
    font.setHintingPreference(hintingPreference);
    font.setPixelSize(12.0);

    QRawFont rawFont = QRawFont::fromFont(font, QFontDatabase::Any);
    QCOMPARE(rawFont.familyName(), QString::fromLatin1("QtBidiTestFont"));
    QCOMPARE(rawFont.pixelSize(), 12.0);

    rawFont = QRawFont::fromFont(font, QFontDatabase::Hebrew);
    QCOMPARE(rawFont.familyName(), QString::fromLatin1("QtBidiTestFont"));
    QCOMPARE(rawFont.pixelSize(), 12.0);

    QString arabicText = QFontDatabase::writingSystemSample(QFontDatabase::Arabic);

    QTextLayout layout;
    layout.setFont(font);
    layout.setText(arabicText);
    layout.beginLayout();
    layout.createLine();
    layout.endLayout();

    QList<QGlyphRun> glyphRuns = layout.glyphRuns();
    QCOMPARE(glyphRuns.size(), 1);

    QGlyphRun glyphs = glyphRuns.at(0);
    QRawFont layoutFont = glyphs.rawFont();
    QVERIFY(layoutFont.familyName() != QString::fromLatin1("QtBidiTestFont"));
    QCOMPARE(layoutFont.pixelSize(), 12.0);

    rawFont = QRawFont::fromFont(font, QFontDatabase::Arabic);
    QCOMPARE(rawFont.familyName(), layoutFont.familyName());
    QCOMPARE(rawFont.pixelSize(), 12.0);

    fontDatabase.removeApplicationFont(id);
}

qreal QmlConsoleItemDelegate::layoutText(QTextLayout &tl, int width,
                                         bool *showFileLineInfo) const
{
    qreal height = 0;
    tl.beginLayout();
    while (true) {
        QTextLine line = tl.createLine();

        if (!line.isValid())
            break;
        line.setLeadingIncluded(true);
        line.setLineWidth(width);
        if (width < line.naturalTextWidth() && showFileLineInfo)
            *showFileLineInfo = false;
        line.setPosition(QPoint(0, height));
        height += line.height();
    }
    tl.endLayout();
    return height;
}

/// Calculate single line layout for given text with specified font.
/// This function automatically add ellipsis text if the naural width
/// is larger than given region.
/// \layout The result layout.
/// \font The font object.
/// \string The text needs to be layouted.
/// \align Alignment.
/// \rect The region.
/// \ellipsis Add ellipse to left or right if necessary.
/// Returns the line height.
int calculateSingleLineLayout(QTextLayout & layout,
                              const QFont & font,
                              const QString & string,
                              const Qt::Alignment align,
                              const QRect & rect,
                              const Qt::TextElideMode ellipsis)
{
    QFontMetrics fm(font);

    // Check if we need to add ellipsis.
    QString result_string = string;
    int width = ellipsisText(string, fm, rect.width(),
                             ellipsis, result_string);

    // Construct the layout.
    layout.clearLayout();
    layout.setCacheEnabled(false);
    layout.setText(result_string);
    layout.setFont(font);
    layout.beginLayout();
    QTextLine line = layout.createLine();
    if (line.isValid())
    {
        line.setLineWidth(rect.width());
    }
    layout.endLayout();

    // Calculate the position.
    int x = rect.left();
    int y = rect.top();
    int h = static_cast<int>(line.height());

    if (align & Qt::AlignHCenter)
    {
        x = ((rect.width() - width) >> 1) + x;
    }

void QStaticTextPrivate::paintText(const QPointF &topLeftPosition, QPainter *p)
{
    bool preferRichText = textFormat == Qt::RichText
                          || (textFormat == Qt::AutoText && Qt::mightBeRichText(text));

    if (!preferRichText) {
        QTextLayout textLayout;
        textLayout.setText(text);
        textLayout.setFont(font);
        textLayout.setTextOption(textOption);

        qreal leading = QFontMetricsF(font).leading();
        qreal height = -leading;

        textLayout.beginLayout();
        while (1) {
            QTextLine line = textLayout.createLine();
            if (!line.isValid())
                break;

            if (textWidth >= 0.0)
                line.setLineWidth(textWidth);
            height += leading;
            line.setPosition(QPointF(0.0, height));
            height += line.height();
        }
        textLayout.endLayout();

        actualSize = textLayout.boundingRect().size();
        textLayout.draw(p, topLeftPosition);
    } else {
        QTextDocument document;
#ifndef QT_NO_CSSPARSER
        QColor color = p->pen().color();
        document.setDefaultStyleSheet(QString::fromLatin1("body { color: #%1%2%3 }")
                                      .arg(QString::number(color.red(), 16), 2, QLatin1Char('0'))
                                      .arg(QString::number(color.green(), 16), 2, QLatin1Char('0'))
                                      .arg(QString::number(color.blue(), 16), 2, QLatin1Char('0')));
#endif
        document.setDefaultFont(font);
        document.setDocumentMargin(0.0);        
#ifndef QT_NO_TEXTHTMLPARSER
        document.setHtml(text);
#else
        document.setPlainText(text);
#endif
        if (textWidth >= 0.0)
            document.setTextWidth(textWidth);
        else
            document.adjustSize();
        document.setDefaultTextOption(textOption);

        p->save();
        p->translate(topLeftPosition);
        QAbstractTextDocumentLayout::PaintContext ctx;
        ctx.palette.setColor(QPalette::Text, p->pen().color());
        document.documentLayout()->draw(p, ctx);
        p->restore();

        if (textWidth >= 0.0)
            document.adjustSize(); // Find optimal size

        actualSize = document.size();
    }
}

void QQuickTextNodeEngine::addTextBlock(QTextDocument *textDocument, const QTextBlock &block, const QPointF &position, const QColor &textColor, const QColor &anchorColor, int selectionStart, int selectionEnd)
{
    Q_ASSERT(textDocument);
#ifndef QT_NO_IM
    int preeditLength = block.isValid() ? block.layout()->preeditAreaText().length() : 0;
    int preeditPosition = block.isValid() ? block.layout()->preeditAreaPosition() : -1;
#endif

    QVarLengthArray<QTextLayout::FormatRange> colorChanges;
    mergeFormats(block.layout(), &colorChanges);

    QPointF blockPosition = textDocument->documentLayout()->blockBoundingRect(block).topLeft() + position;
    if (QTextList *textList = block.textList()) {
        QPointF pos = blockPosition;
        QTextLayout *layout = block.layout();
        if (layout->lineCount() > 0) {
            QTextLine firstLine = layout->lineAt(0);
            Q_ASSERT(firstLine.isValid());

            setCurrentLine(firstLine);

            QRectF textRect = firstLine.naturalTextRect();
            pos += textRect.topLeft();
            if (block.textDirection() == Qt::RightToLeft)
                pos.rx() += textRect.width();

            const QTextCharFormat charFormat = block.charFormat();
            QFont font(charFormat.font());
            QFontMetricsF fontMetrics(font);
            QTextListFormat listFormat = textList->format();

            QString listItemBullet;
            switch (listFormat.style()) {
            case QTextListFormat::ListCircle:
                listItemBullet = QChar(0x25E6); // White bullet
                break;
            case QTextListFormat::ListSquare:
                listItemBullet = QChar(0x25AA); // Black small square
                break;
            case QTextListFormat::ListDecimal:
            case QTextListFormat::ListLowerAlpha:
            case QTextListFormat::ListUpperAlpha:
            case QTextListFormat::ListLowerRoman:
            case QTextListFormat::ListUpperRoman:
                listItemBullet = textList->itemText(block);
                break;
            default:
                listItemBullet = QChar(0x2022); // Black bullet
                break;
            };

            QSizeF size(fontMetrics.width(listItemBullet), fontMetrics.height());
            qreal xoff = fontMetrics.width(QLatin1Char(' '));
            if (block.textDirection() == Qt::LeftToRight)
                xoff = -xoff - size.width();
            setPosition(pos + QPointF(xoff, 0));

            QTextLayout layout;
            layout.setFont(font);
            layout.setText(listItemBullet); // Bullet
            layout.beginLayout();
            QTextLine line = layout.createLine();
            line.setPosition(QPointF(0, 0));
            layout.endLayout();

            QList<QGlyphRun> glyphRuns = layout.glyphRuns();
            for (int i=0; i<glyphRuns.size(); ++i)
                addUnselectedGlyphs(glyphRuns.at(i));
        }
    }

    int textPos = block.position();
    QTextBlock::iterator blockIterator = block.begin();

    while (!blockIterator.atEnd()) {
        QTextFragment fragment = blockIterator.fragment();
        QString text = fragment.text();
        if (text.isEmpty())
            continue;

        QTextCharFormat charFormat = fragment.charFormat();
        QFont font(charFormat.font());
        QFontMetricsF fontMetrics(font);

        int fontHeight = fontMetrics.descent() + fontMetrics.ascent();
        int valign = charFormat.verticalAlignment();
        if (valign == QTextCharFormat::AlignSuperScript)
            setPosition(QPointF(blockPosition.x(), blockPosition.y() - fontHeight / 2));
        else if (valign == QTextCharFormat::AlignSubScript)
            setPosition(QPointF(blockPosition.x(), blockPosition.y() + fontHeight / 6));
        else
            setPosition(blockPosition);

        if (text.contains(QChar::ObjectReplacementCharacter)) {
            QTextFrame *frame = qobject_cast<QTextFrame *>(textDocument->objectForFormat(charFormat));
            if (frame && frame->frameFormat().position() == QTextFrameFormat::InFlow) {
                int blockRelativePosition = textPos - block.position();
                QTextLine line = block.layout()->lineForTextPosition(blockRelativePosition);
                if (!currentLine().isValid()
                        || line.lineNumber() != currentLine().lineNumber()) {
//.........这里部分代码省略.........

void TextDocumentLayout::layoutBlock(const QTextBlock &block)
{
    QTextDocument *doc = document();
    qreal margin = doc->documentMargin();
    qreal blockMaximumWidth = 0;

    qreal height = 0;
    QTextLayout *tl = block.layout();
    QTextOption option = doc->defaultTextOption();
    tl->setTextOption(option);

    int extraMargin = 0;
    if (option.flags() & QTextOption::AddSpaceForLineAndParagraphSeparators) {
        QFontMetrics fm(block.charFormat().font());
        extraMargin += fm.width(QChar(0x21B5));
    }
    tl->beginLayout();
    qreal availableWidth = d->width;
    if (availableWidth <= 0) {
        availableWidth = qreal(INT_MAX); // similar to text edit with pageSize.width == 0
    }
    availableWidth -= 2*margin + extraMargin;
    qreal indentMargin = 0;
    while (1) {
        QTextLine line = tl->createLine();
        if (!line.isValid())
            break;
        line.setLeadingIncluded(true);
        line.setLineWidth(availableWidth - indentMargin);
        line.setPosition(QPointF(margin + indentMargin, height));
        if(!height) //enter only in the first iteration
        {
            indentMargin = indentWidth(block);
        }
        height += line.height();
        blockMaximumWidth = qMax(blockMaximumWidth, line.naturalTextWidth() + 2*margin);
    }
    tl->endLayout();

    int previousLineCount = doc->lineCount();
    const_cast<QTextBlock&>(block).setLineCount(block.isVisible() ? tl->lineCount() : 0);
    int lineCount = doc->lineCount();

    bool emitDocumentSizeChanged = previousLineCount != lineCount;
    if (blockMaximumWidth > d->maximumWidth) {
        // new longest line
        d->maximumWidth = blockMaximumWidth;
        d->maximumWidthBlockNumber = block.blockNumber();
        emitDocumentSizeChanged = true;
    } else if (block.blockNumber() == d->maximumWidthBlockNumber && blockMaximumWidth < d->maximumWidth) {
        // longest line shrinking
        QTextBlock b = doc->firstBlock();
        d->maximumWidth = 0;
        QTextBlock maximumBlock;
        while (b.isValid()) {
            qreal blockMaximumWidth = blockWidth(b);
            if (blockMaximumWidth > d->maximumWidth) {
                d->maximumWidth = blockMaximumWidth;
                maximumBlock = b;
            }
            b = b.next();
        }
        if (maximumBlock.isValid()) {
            d->maximumWidthBlockNumber = maximumBlock.blockNumber();
            emitDocumentSizeChanged = true;
        }
    }
    if (emitDocumentSizeChanged)// && !d->blockDocumentSizeChanged)
        emit documentSizeChanged(documentSize());

    emit updateBlock(block);
}

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();

}