basetexteditor.cpp

            if (drawCursorAsBlock) {
                if (context.cursorPosition == blpos + bllen - 1) {
                    drawCursorAsBlock = false;
                } else {
                    QTextLayout::FormatRange o;
                    o.start = context.cursorPosition - blpos;
                    o.length = 1;
                    o.format.setForeground(palette().base());
                    o.format.setBackground(palette().text());
                    selections.append(o);
                }
            }


            layout->draw(&painter, offset, selections, er);

            if ((drawCursor && !drawCursorAsBlock)
                || (editable && context.cursorPosition < -1
                    && !layout->preeditAreaText().isEmpty())) {
                int cpos = context.cursorPosition;
                if (cpos < -1)
                    cpos = layout->preeditAreaPosition() - (cpos + 2);
                else
                    cpos -= blpos;
                layout->drawCursor(&painter, offset, cpos, cursorWidth());
            }
        }

        offset.ry() += r.height();

        if (offset.y() > viewportRect.height())
            break;
        block = block.next();
        if (!block.isVisible()) {
            if (block.blockNumber() == d->visibleCollapsedBlockNumber) {
                visibleCollapsedBlock = block;
                visibleCollapsedBlockOffset = offset + QPointF(0,1);
            }

            // invisible blocks do have zero line count
            block = doc->findBlockByLineNumber(block.firstLineNumber());
        }
    }

    if (backgroundVisible() && !block.isValid() && offset.y() <= er.bottom()
        && (centerOnScroll() || verticalScrollBar()->maximum() == verticalScrollBar()->minimum())) {
        painter.fillRect(QRect(QPoint((int)er.left(), (int)offset.y()), er.bottomRight()), palette().background());
    }

    //end QPlainTextEdit::paintEvent()

    delete blockSelection;

    offset = contentOffset();
    block = firstVisibleBlock();

    int top = (int)blockBoundingGeometry(block).translated(offset).top();
    int bottom = top + (int)blockBoundingRect(block).height();

    QTextCursor cursor = textCursor();
    bool hasSelection = cursor.hasSelection();
    int selectionStart = cursor.selectionStart();
    int selectionEnd = cursor.selectionEnd();


    while (block.isValid() && top <= e->rect().bottom()) {
        QTextBlock nextBlock = block.next();
        QTextBlock nextVisibleBlock = nextBlock;

        if (!nextVisibleBlock.isVisible())
            // invisible blocks do have zero line count
            nextVisibleBlock = doc->findBlockByLineNumber(nextVisibleBlock.firstLineNumber());
        if (block.isVisible() && bottom >= e->rect().top()) {
            if (d->m_displaySettings.m_visualizeWhitespace) {
                QTextLayout *layout = block.layout();
                int lineCount = layout->lineCount();
                if (lineCount >= 2 || !nextBlock.isValid()) {
                    painter.save();
                    painter.setPen(Qt::lightGray);
                    for (int i = 0; i < lineCount-1; ++i) { // paint line wrap indicator
                        QTextLine line = layout->lineAt(i);
                        QRectF lineRect = line.naturalTextRect().translated(offset.x(), top);
                        QChar visualArrow((ushort)0x21b5);
                        painter.drawText(static_cast<int>(lineRect.right()),
                                         static_cast<int>(lineRect.top() + line.ascent()), visualArrow);
                    }
                    if (!nextBlock.isValid()) { // paint EOF symbol
                        QTextLine line = layout->lineAt(lineCount-1);
                        QRectF lineRect = line.naturalTextRect().translated(offset.x(), top);
                        int h = 4;
                        lineRect.adjust(0, 0, -1, -1);
                        QPainterPath path;
                        QPointF pos(lineRect.topRight() + QPointF(h+4, line.ascent()));
                        path.moveTo(pos);
                        path.lineTo(pos + QPointF(-h, -h));
                        path.lineTo(pos + QPointF(0, -2*h));
                        path.lineTo(pos + QPointF(h, -h));
                        path.closeSubpath();
                        painter.setBrush(painter.pen().color());
                        painter.drawPath(path);
                    }
                    painter.restore();
                }
            }

            if (nextBlock.isValid() && !nextBlock.isVisible()) {

                bool selectThis = (hasSelection
                                   && nextBlock.position() >= selectionStart
                                   && nextBlock.position() < selectionEnd);
                if (selectThis) {
                    painter.save();
                    painter.setBrush(palette().highlight());
                }

                QTextLayout *layout = block.layout();
                QTextLine line = layout->lineAt(layout->lineCount()-1);
                QRectF lineRect = line.naturalTextRect().translated(offset.x(), top);
                lineRect.adjust(0, 0, -1, -1);

                QRectF collapseRect(lineRect.right() + 12,
                                    lineRect.top(),
                                    fontMetrics().width(QLatin1String(" {...}; ")),
                                    lineRect.height());
                painter.setRenderHint(QPainter::Antialiasing, true);
                painter.translate(.5, .5);
                painter.drawRoundedRect(collapseRect.adjusted(0, 0, 0, -1), 3, 3);
                painter.setRenderHint(QPainter::Antialiasing, false);
                painter.translate(-.5, -.5);

                QString replacement = QLatin1String("...");

                QTextBlock info = block;
                if (block.userData()
                    && static_cast<TextBlockUserData*>(block.userData())->collapseMode() == TextBlockUserData::CollapseAfter)
                    ;
                else if (block.next().userData()
                         && static_cast<TextBlockUserData*>(block.next().userData())->collapseMode()
                         == TextBlockUserData::CollapseThis) {
                    replacement.prepend(nextBlock.text().trimmed().left(1));
                    info = nextBlock;
                }


                block = nextVisibleBlock.previous();
                if (!block.isValid())
                    block = doc->lastBlock();

                if (info.userData()
                    && static_cast<TextBlockUserData*>(info.userData())->collapseIncludesClosure()) {
                    QString right = block.text().trimmed();
                    if (right.endsWith(QLatin1Char(';'))) {
                        right.chop(1);
                        right = right.trimmed();
                        replacement.append(right.right(right.endsWith(QLatin1Char('/')) ? 2 : 1));
                        replacement.append(QLatin1Char(';'));
                    } else {
                        replacement.append(right.right(right.endsWith(QLatin1Char('/')) ? 2 : 1));
                    }
                }
                if (selectThis)
                    painter.setPen(palette().highlightedText().color());
                painter.drawText(collapseRect, Qt::AlignCenter, replacement);
                if (selectThis)
                    painter.restore();
            }
        }

        block = nextVisibleBlock;
        top = bottom;
        bottom = top + (int)blockBoundingRect(block).height();
    }

    if (visibleCollapsedBlock.isValid() ) {
        int margin = doc->documentMargin();
        qreal maxWidth = 0;
        qreal blockHeight = 0;
        QTextBlock b = visibleCollapsedBlock;

        while (!b.isVisible() && visibleCollapsedBlockOffset.y() + blockHeight <= e->rect().bottom()) {
            b.setVisible(true); // make sure block bounding rect works
            QRectF r = blockBoundingRect(b).translated(visibleCollapsedBlockOffset);

            QTextLayout *layout = b.layout();
            for (int i = layout->lineCount()-1; i >= 0; --i)
                maxWidth = qMax(maxWidth, layout->lineAt(i).naturalTextWidth() + margin);

            blockHeight += r.height();

            b.setVisible(false); // restore previous state
            b = b.next();
        }

        painter.save();
        painter.setRenderHint(QPainter::Antialiasing, true);
        painter.translate(.5, .5);
        QColor color = blendColor;
//        color.setAlpha(240); // someone thinks alpha blending looks messy
        painter.setBrush(color);
        painter.drawRoundedRect(QRectF(visibleCollapsedBlockOffset.x(),
                                       visibleCollapsedBlockOffset.y(),
                                       maxWidth, blockHeight).adjusted(0, 0, 0, 0), 3, 3);
        painter.restore();

        QTextBlock end = b;
        b = visibleCollapsedBlock;
        while (b != end) {
            b.setVisible(true); // make sure block bounding rect works
            QRectF r = blockBoundingRect(b).translated(visibleCollapsedBlockOffset);
            QTextLayout *layout = b.layout();
            QVector<QTextLayout::FormatRange> selections;
            d->highlightSearchResults(b, &selections);
            layout->draw(&painter, visibleCollapsedBlockOffset, selections, er);

            b.setVisible(false); // restore previous state
            visibleCollapsedBlockOffset.ry() += r.height();
            b = b.next();
        }
    }

    if (d->m_animator && d->m_animator->isRunning()) {
        QTextCursor cursor = textCursor();
        cursor.setPosition(d->m_animator->position());
        d->m_animator->draw(&painter, cursorRect(cursor).topLeft());
    }


    if (lineX > 0) {
        const QColor bg = palette().base().color();
        QColor col = (bg.value() > 128) ? Qt::black : Qt::white;
        col.setAlpha(32);
        painter.setPen(QPen(col, 0));
        painter.drawLine(QPointF(lineX, 0), QPointF(lineX, viewport()->height()));
    }
}

QWidget *BaseTextEditor::extraArea() const
{
    return d->m_extraArea;
}

int BaseTextEditor::extraAreaWidth(int *markWidthPtr) const
{
    TextEditDocumentLayout *documentLayout = qobject_cast<TextEditDocumentLayout*>(document()->documentLayout());
    if (!documentLayout)
        return 0;

    if (!d->m_marksVisible && documentLayout->hasMarks)
        d->m_marksVisible = true;

    int space = 0;
    const QFontMetrics fm(d->m_extraArea->fontMetrics());

    if (d->m_lineNumbersVisible) {
        int digits = 2;
        int max = qMax(1, blockCount());
        while (max >= 100) {
            max /= 10;
            ++digits;
        }
        space += fm.width(QLatin1Char('9')) * digits;
    }
    int markWidth = 0;

    if (d->m_marksVisible) {
        markWidth += fm.lineSpacing();
//     if (documentLayout->doubleMarkCount)
//         markWidth += fm.lineSpacing() / 3;
        space += markWidth;
    } else {
        space += 2;
    }

    if (markWidthPtr)
        *markWidthPtr = markWidth;

    space += 4;

    if (d->m_codeFoldingVisible)
        space += collapseBoxWidth(fm);
    return space;
}

void BaseTextEditor::slotUpdateExtraAreaWidth()
{
    if (isLeftToRight())
        setViewportMargins(extraAreaWidth(), 0, 0, 0);
    else
        setViewportMargins(0, 0, extraAreaWidth(), 0);
}

static void drawRectBox(QPainter *painter, const QRect &rect, bool start, bool end,
                        const QPalette &pal)
{
    painter->save();
    painter->setRenderHint(QPainter::Antialiasing, false);

    QRgb b = pal.base().color().rgb();
    QRgb h = pal.highlight().color().rgb();
    QColor c = StyleHelper::mergedColors(b,h, 50);

    QLinearGradient grad(rect.topLeft(), rect.topRight());
    grad.setColorAt(0, c.lighter(110));
    grad.setColorAt(1, c.lighter(130));
    QColor outline = c;
    QRect r = rect;

    painter->fillRect(rect, grad);
    painter->setPen(outline);
    if (start)
        painter->drawLine(rect.topLeft() + QPoint(1, 0), rect.topRight() -  QPoint(1, 0));
    if (end)
        painter->drawLine(rect.bottomLeft() + QPoint(1, 0), rect.bottomRight() -  QPoint(1, 0));

    painter->drawLine(rect.topRight() + QPoint(0, start ? 1 : 0), rect.bottomRight() - QPoint(0, end ? 1 : 0));
    painter->drawLine(rect.topLeft() + QPoint(0, start ? 1 : 0), rect.bottomLeft() - QPoint(0, end ? 1 : 0));

    painter->restore();
}

void BaseTextEditor::extraAreaPaintEvent(QPaintEvent *e)
{
    QTextDocument *doc = document();
    TextEditDocumentLayout *documentLayout = qobject_cast<TextEditDocumentLayout*>(doc->documentLayout());
    QTC_ASSERT(documentLayout, return);

    int selStart = textCursor().selectionStart();
    int selEnd = textCursor().selectionEnd();

    const QColor baseColor = palette().base().color();
    QPalette pal = d->m_extraArea->palette();
    pal.setCurrentColorGroup(QPalette::Active);
    QPainter painter(d->m_extraArea);
    QFontMetrics fm(painter.fontMetrics());
    int fmLineSpacing = fm.lineSpacing();

    int markWidth = 0;
    if (d->m_marksVisible)
        markWidth += fm.lineSpacing();
//     if (documentLayout->doubleMarkCount)
//         markWidth += fm.lineSpacing() / 3;

    const int collapseColumnWidth = d->m_codeFoldingVisible ? collapseBoxWidth(fm): 0;
    const int extraAreaWidth = d->m_extraArea->width() - collapseColumnWidth;

    painter.fillRect(e->rect(), pal.color(QPalette::Base));
    painter.fillRect(e->rect().intersected(QRect(0, 0, extraAreaWidth, INT_MAX)),
                     pal.color(QPalette::Background));

    QTextBlock block = firstVisibleBlock();
    int blockNumber = block.blockNumber();
    int top = (int) blockBoundingGeometry(block).translated(contentOffset()).top();
    int bottom = top;

    while (block.isValid() && top <= e->rect().bottom()) {

        top = bottom;
        bottom = top + (int)blockBoundingRect(block).height();
        QTextBlock nextBlock = block.next();

        QTextBlock nextVisibleBlock = nextBlock;
        int nextVisibleBlockNumber = blockNumber + 1;

        if (!nextVisibleBlock.isVisible()) {
            // invisible blocks do have zero line count
            nextVisibleBlock = doc->findBlockByLineNumber(nextVisibleBlock.firstLineNumber());
            nextVisibleBlockNumber = nextVisibleBlock.blockNumber();
        }

        painter.setPen(pal.color(QPalette::Dark));

        if (d->m_codeFoldingVisible || d->m_marksVisible) {
            painter.save();
            painter.setRenderHint(QPainter::Antialiasing, false);

            int previousBraceDepth = block.previous().userState();
            if (previousBraceDepth >= 0)
                previousBraceDepth >>= 8;
            else
                previousBraceDepth = 0;

            int braceDepth = block.userState();
            if (!nextBlock.isVisible()) {
                QTextBlock lastInvisibleBlock = nextVisibleBlock.previous();
                if (!lastInvisibleBlock.isValid())
                    lastInvisibleBlock = doc->lastBlock();
                braceDepth = lastInvisibleBlock.userState();
            }
            if (braceDepth >= 0)
                braceDepth >>= 8;
            else
                braceDepth = 0;

            if (TextBlockUserData *userData = static_cast<TextBlockUserData*>(block.userData())) {
                if (d->m_marksVisible) {
                    int xoffset = 0;
                    foreach (ITextMark *mrk, userData->marks()) {
                        int x = 0;
                        int radius = fmLineSpacing - 1;
                        QRect r(x + xoffset, top, radius, radius);
                        mrk->icon().paint(&painter, r, Qt::AlignCenter);
                        xoffset += 2;
                    }
                }
            }

            if (d->m_codeFoldingVisible) {

                bool collapseThis = false;
                bool collapseAfter = false;
                bool hasClosingCollapse = false;

                if (TextBlockUserData *userData = static_cast<TextBlockUserData*>(block.userData())) {
                    if (!userData->ifdefedOut()) {
                        collapseAfter = (userData->collapseMode() == TextBlockUserData::CollapseAfter);
                        collapseThis = (userData->collapseMode() == TextBlockUserData::CollapseThis);
                        hasClosingCollapse = userData->hasClosingCollapse() && (previousBraceDepth > 0);
                    }
                }

                int extraAreaHighlightCollapseBlockNumber = -1;
                int extraAreaHighlightCollapseEndBlockNumber = -1;
                bool endIsVisible = false;
                if (!d->m_highlightBlocksInfo.isEmpty()) {
                    extraAreaHighlightCollapseBlockNumber =  d->m_highlightBlocksInfo.open.last();
                    extraAreaHighlightCollapseEndBlockNumber =  d->m_highlightBlocksInfo.close.first();
                    endIsVisible = doc->findBlockByNumber(extraAreaHighlightCollapseEndBlockNumber).isVisible();

                    QTextBlock before = doc->findBlockByNumber(extraAreaHighlightCollapseBlockNumber-1);
                    if (TextBlockUserData::hasCollapseAfter(before)) {
                        extraAreaHighlightCollapseBlockNumber--;
                    }
                }

                TextBlockUserData *nextBlockUserData = TextEditDocumentLayout::testUserData(nextBlock);

                bool collapseNext = nextBlockUserData
                                    && nextBlockUserData->collapseMode() == TextBlockUserData::CollapseThis
                                    && !nextBlockUserData->ifdefedOut();

                bool nextHasClosingCollapse = nextBlockUserData
                                              && nextBlockUserData->hasClosingCollapseInside()
                                              && nextBlockUserData->ifdefedOut();

                bool drawBox = ((collapseAfter || collapseNext) && !nextHasClosingCollapse);
                bool active = blockNumber == extraAreaHighlightCollapseBlockNumber;
                bool drawStart = drawBox && active;
                bool drawEnd = blockNumber == extraAreaHighlightCollapseEndBlockNumber || (drawStart && !endIsVisible);
                bool hovered = blockNumber >= extraAreaHighlightCollapseBlockNumber
                               && blockNumber <= extraAreaHighlightCollapseEndBlockNumber;

                int boxWidth = collapseBoxWidth(fm);
                if (hovered) {
                    QRect box = QRect(extraAreaWidth + 1, top, boxWidth - 2, bottom - top);
                    drawRectBox(&painter, box, drawStart, drawEnd, pal);
                }

                if (drawBox) {
                    bool expanded = nextBlock.isVisible();
                    int size = boxWidth/4;
                    QRect box(extraAreaWidth + size, top + size,
                              2 * (size) + 1, 2 * (size) + 1);
                    drawFoldingMarker(&painter, pal, box, expanded, active, hovered);
                }
            }

            painter.restore();
        }


        if (d->m_revisionsVisible && block.revision() != documentLayout->lastSaveRevision) {
            painter.save();
            painter.setRenderHint(QPainter::Antialiasing, false);
            if (block.revision() < 0)
                painter.setPen(QPen(Qt::darkGreen, 2));
            else
                painter.setPen(QPen(Qt::red, 2));
            painter.drawLine(extraAreaWidth - 1, top, extraAreaWidth - 1, bottom - 1);
            painter.restore();
        }

        if (d->m_lineNumbersVisible) {
            const QString &number = QString::number(blockNumber + 1);
            bool selected = (
                    (selStart < block.position() + block.length()
                    && selEnd > block.position())
                    || (selStart == selEnd && selStart == block.position())
                    );
            if (selected) {
                painter.save();
                QFont f = painter.font();
                f.setBold(d->m_currentLineNumberFormat.font().bold());
                f.setItalic(d->m_currentLineNumberFormat.font().italic());
                painter.setFont(f);
                painter.setPen(d->m_currentLineNumberFormat.foreground().color());
            }
            painter.drawText(markWidth, top, extraAreaWidth - markWidth - 4, fm.height(), Qt::AlignRight, number);
            if (selected)
                painter.restore();
        }

        block = nextVisibleBlock;
        blockNumber = nextVisibleBlockNumber;
    }
}

void BaseTextEditor::drawFoldingMarker(QPainter *painter, const QPalette &pal,
                                       const QRect &rect,
                                       bool expanded,
                                       bool active,
                                       bool hovered) const
{
    Q_UNUSED(active)
    Q_UNUSED(hovered)
    QStyle *s = style();
    if (ManhattanStyle *ms = qobject_cast<ManhattanStyle*>(s))
        s = ms->systemStyle();

    if (!qstrcmp(s->metaObject()->className(), "OxygenStyle")) {
        painter->save();
        painter->setPen(Qt::NoPen);
        int size = rect.size().width();
        int sqsize = 2*(size/2);

        QColor textColor = pal.buttonText().color();
        QColor brushColor = textColor;

        textColor.setAlpha(100);
        brushColor.setAlpha(100);

        QPolygon a;
        if (expanded) {
            // down arrow
            a.setPoints(3, 0, sqsize/3,  sqsize/2, sqsize  - sqsize/3,  sqsize, sqsize/3);
        } else {
            // right arrow
            a.setPoints(3, sqsize - sqsize/3, sqsize/2,  sqsize/2 - sqsize/3, 0,  sqsize/2 - sqsize/3, sqsize);
            painter->setBrush(brushColor);
        }
        painter->translate(0.5, 0.5);
        painter->setRenderHint(QPainter::Antialiasing);
        painter->translate(rect.topLeft());
        painter->setPen(textColor);
        painter->setBrush(textColor);
        painter->drawPolygon(a);
        painter->restore();
    } else {
        QStyleOptionViewItemV2 opt;
        opt.rect = rect;
        opt.state = QStyle::State_Active | QStyle::State_Item | QStyle::State_Children;
        if (expanded)
            opt.state |= QStyle::State_Open;
        if (active)
            opt.state |= QStyle::State_MouseOver | QStyle::State_Enabled | QStyle::State_Selected;
        if (hovered)
            opt.palette.setBrush(QPalette::Window, pal.highlight());

         // QGtkStyle needs a small correction to draw the marker in the right place
        if (!qstrcmp(s->metaObject()->className(), "QGtkStyle"))
           opt.rect.translate(-2, 0);
        else if (!qstrcmp(s->metaObject()->className(), "QMacStyle"))
            opt.rect.translate(-1, 0);

        s->drawPrimitive(QStyle::PE_IndicatorBranch, &opt, painter, this);
    }
}

void BaseTextEditor::slotModificationChanged(bool m)
{
    if (m)
        return;

    QTextDocument *doc = document();
    TextEditDocumentLayout *documentLayout = qobject_cast<TextEditDocumentLayout*>(doc->documentLayout());
    QTC_ASSERT(documentLayout, return);
    int oldLastSaveRevision = documentLayout->lastSaveRevision;
    documentLayout->lastSaveRevision = doc->revision();

    if (oldLastSaveRevision != documentLayout->lastSaveRevision) {
        QTextBlock block = doc->begin();
        while (block.isValid()) {
            if (block.revision() < 0 || block.revision() != oldLastSaveRevision) {
                block.setRevision(-documentLayout->lastSaveRevision - 1);
            } else {
                block.setRevision(documentLayout->lastSaveRevision);
            }
            block = block.next();
        }
    }
    d->m_extraArea->update();
}

void BaseTextEditor::slotUpdateRequest(const QRect &r, int dy)
{
    if (dy)
        d->m_extraArea->scroll(0, dy);
    else if (r.width() > 4) { // wider than cursor width, not just cursor blinking
        d->m_extraArea->update(0, r.y(), d->m_extraArea->width(), r.height());
    }

    if (r.contains(viewport()->rect()))
        slotUpdateExtraAreaWidth();
}

void BaseTextEditor::saveCurrentCursorPositionForNavigation()
{
    d->m_lastCursorChangeWasInteresting = true;
    d->m_tempNavigationState = saveState();
}

void BaseTextEditor::updateCurrentLineHighlight()
{
    QList<QTextEdit::ExtraSelection> extraSelections;

    if (d->m_highlightCurrentLine) {
        QTextEdit::ExtraSelection sel;
        sel.format.setBackground(d->m_currentLineFormat.background());
        sel.format.setProperty(QTextFormat::FullWidthSelection, true);
        sel.cursor = textCursor();
        sel.cursor.clearSelection();
        extraSelections.append(sel);
    }

    setExtraSelections(CurrentLineSelection, extraSelections);
}

void BaseTextEditor::slotCursorPositionChanged()
{
    if (!d->m_contentsChanged && d->m_lastCursorChangeWasInteresting) {
        Core::EditorManager::instance()->addCurrentPositionToNavigationHistory(editableInterface(), d->m_tempNavigationState);
        d->m_lastCursorChangeWasInteresting = false;
    } else if (d->m_contentsChanged) {
        saveCurrentCursorPositionForNavigation();
    }

    if (d->m_parenthesesMatchingEnabled) {
        // Delay update when no matching is displayed yet, to avoid flicker
        if (extraSelections(ParenthesesMatchingSelection).isEmpty()) {
            d->m_parenthesesMatchingTimer->start(50);
        } else {
             // use 0-timer, not direct call, to give the syntax highlighter a chance
            // to update the parantheses information
            d->m_parenthesesMatchingTimer->start(0);
        }
    }

    updateCurrentLineHighlight();

    if (d->m_displaySettings.m_highlightBlocks) {
        QTextCursor cursor = textCursor();
        d->extraAreaHighlightCollapseBlockNumber = cursor.blockNumber();
        d->extraAreaHighlightCollapseColumn = cursor.position() - cursor.block().position();
        d->m_highlightBlocksTimer->start(100);
    }
}

void BaseTextEditor::slotUpdateBlockNotify(const QTextBlock &block)
{
    static bool blockRecursion = false;
    if (blockRecursion)
        return;
    if (block.previous().isValid() && block.userState() != block.previous().userState()) {
        /* The syntax highlighting state changes. This opens up for
           the possibility that the paragraph has braces that support
           code folding. In this case, do the save thing and also
           update the previous block, which might contain a collapse
           box which now is invalid.*/
        blockRecursion = true;
        emit requestBlockUpdate(block.previous());
        blockRecursion = false;
    }
}

void BaseTextEditor::timerEvent(QTimerEvent *e)
{
    if (e->timerId() == d->autoScrollTimer.timerId()) {
        const QPoint globalPos = QCursor::pos();
        const QPoint pos = d->m_extraArea->mapFromGlobal(globalPos);
        QRect visible = d->m_extraArea->rect();
        verticalScrollBar()->triggerAction( pos.y() < visible.center().y() ?
                                            QAbstractSlider::SliderSingleStepSub
                                            : QAbstractSlider::SliderSingleStepAdd);
        QMouseEvent ev(QEvent::MouseMove, pos, globalPos, Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
        extraAreaMouseEvent(&ev);
        int delta = qMax(pos.y() - visible.top(), visible.bottom() - pos.y()) - visible.height();
        if (delta < 7)
            delta = 7;
        int timeout = 4900 / (delta * delta);
        d->autoScrollTimer.start(timeout, this);

    } else if (e->timerId() == d->collapsedBlockTimer.timerId()) {
        d->visibleCollapsedBlockNumber = d->suggestedVisibleCollapsedBlockNumber;
        d->suggestedVisibleCollapsedBlockNumber = -1;
        d->collapsedBlockTimer.stop();
        viewport()->update();
    }
    QPlainTextEdit::timerEvent(e);
}


void BaseTextEditorPrivate::clearVisibleCollapsedBlock()
{
    if (suggestedVisibleCollapsedBlockNumber) {
        suggestedVisibleCollapsedBlockNumber = -1;
        collapsedBlockTimer.stop();
    }
    if (visibleCollapsedBlockNumber >= 0) {
        visibleCollapsedBlockNumber = -1;
        q->viewport()->update();
    }
}


void BaseTextEditor::mouseMoveEvent(QMouseEvent *e)
{
    d->m_lastEventWasBlockSelectionEvent = (e->modifiers() & Qt::AltModifier);
    if (e->buttons() == Qt::NoButton) {
        const QTextBlock collapsedBlock = collapsedBlockAt(e->pos());
        const int blockNumber = collapsedBlock.next().blockNumber();
        if (blockNumber < 0) {
            d->clearVisibleCollapsedBlock();
        } else if (blockNumber != d->visibleCollapsedBlockNumber) {
            d->suggestedVisibleCollapsedBlockNumber = blockNumber;
            d->collapsedBlockTimer.start(40, this);
        }

        // Update the mouse cursor
        if (collapsedBlock.isValid() && !d->m_mouseOnCollapsedMarker) {
            d->m_mouseOnCollapsedMarker = true;
            viewport()->setCursor(Qt::PointingHandCursor);
        } else if (!collapsedBlock.isValid() && d->m_mouseOnCollapsedMarker) {
            d->m_mouseOnCollapsedMarker = false;
            viewport()->setCursor(Qt::IBeamCursor);
        }
    } else {
        QPlainTextEdit::mouseMoveEvent(e);
    }
    if (d->m_lastEventWasBlockSelectionEvent && d->m_inBlockSelectionMode) {
        if (textCursor().atBlockEnd()) {
            d->m_blockSelectionExtraX = qMax(0, e->pos().x() - cursorRect().center().x()) / fontMetrics().averageCharWidth();
        } else {
            d->m_blockSelectionExtraX = 0;
        }
    }
    if (viewport()->cursor().shape() == Qt::BlankCursor)
        viewport()->setCursor(Qt::IBeamCursor);
}

void BaseTextEditor::mousePressEvent(QMouseEvent *e)
{
    if (e->button() == Qt::LeftButton) {
        d->clearBlockSelection(); // just in case, otherwise we might get strange drag and drop

        QTextBlock collapsedBlock = collapsedBlockAt(e->pos());
        if (collapsedBlock.isValid()) {
            toggleBlockVisible(collapsedBlock);
            viewport()->setCursor(Qt::IBeamCursor);
        }
    }
    QPlainTextEdit::mousePressEvent(e);
}

void BaseTextEditor::extraAreaLeaveEvent(QEvent *)
{
    // fake missing mouse move event from Qt
    QMouseEvent me(QEvent::MouseMove, QPoint(-1, -1), Qt::NoButton, 0, 0);
    extraAreaMouseEvent(&me);
}

void BaseTextEditor::extraAreaMouseEvent(QMouseEvent *e)
{
    QTextCursor cursor = cursorForPosition(QPoint(0, e->pos().y()));
    cursor.setPosition(cursor.block().position());

    int markWidth;
    extraAreaWidth(&markWidth);

    if (d->m_codeFoldingVisible
        && e->type() == QEvent::MouseMove && e->buttons() == 0) { // mouse tracking
        // Update which folder marker is highlighted
        const int highlightBlockNumber = d->extraAreaHighlightCollapseBlockNumber;
        const int highlightColumn = d->extraAreaHighlightCollapseColumn;
        d->extraAreaHighlightCollapseBlockNumber = -1;
        d->extraAreaHighlightCollapseColumn = -1;

        if (e->pos().x() > extraArea()->width() - collapseBoxWidth(fontMetrics())) {
            d->extraAreaHighlightCollapseBlockNumber = cursor.blockNumber();
            if (TextBlockUserData::canCollapse(cursor.block())
                || !TextBlockUserData::hasClosingCollapse(cursor.block()))
                d->extraAreaHighlightCollapseColumn = cursor.block().length()-1;
            if (TextBlockUserData::hasCollapseAfter(cursor.block())) {
                d->extraAreaHighlightCollapseBlockNumber++;
                d->extraAreaHighlightCollapseColumn = -1;
                if (TextBlockUserData::canCollapse(cursor.block().next())
                    || !TextBlockUserData::hasClosingCollapse(cursor.block().next()))
                    d->extraAreaHighlightCollapseColumn = cursor.block().next().length()-1;
            }
        } else if (d->m_displaySettings.m_highlightBlocks) {
            QTextCursor cursor = textCursor();
            d->extraAreaHighlightCollapseBlockNumber = cursor.blockNumber();
            d->extraAreaHighlightCollapseColumn = cursor.position() - cursor.block().position();
        }

        if (highlightBlockNumber != d->extraAreaHighlightCollapseBlockNumber
            || highlightColumn != d->extraAreaHighlightCollapseColumn) {
            d->m_highlightBlocksTimer->start(d->m_highlightBlocksInfo.isEmpty() ? 120 : 0);
        }
    }

    // Set whether the mouse cursor is a hand or normal arrow
    if (e->type() == QEvent::MouseMove) {
        bool hand = (e->pos().x() <= markWidth);
        if (hand != (d->m_extraArea->cursor().shape() == Qt::PointingHandCursor))
            d->m_extraArea->setCursor(hand ? Qt::PointingHandCursor : Qt::ArrowCursor);
    }

    if (e->type() == QEvent::MouseButtonPress || e->type() == QEvent::MouseButtonDblClick) {
        if (e->button() == Qt::LeftButton) {
            int boxWidth = collapseBoxWidth(fontMetrics());
            if (d->m_codeFoldingVisible && e->pos().x() > extraArea()->width() - boxWidth) {
                if (!cursor.block().next().isVisible()) {
                    toggleBlockVisible(cursor.block());
                    d->moveCursorVisible(false);
                } else if (collapseBox().contains(e->pos())) {
                    cursor.setPosition(
                            document()->findBlockByNumber(d->m_highlightBlocksInfo.open.last()).position()
                            );
                    QTextBlock c = cursor.block();
                    if (!TextBlockUserData::canCollapse(c))
                        c = c.previous();
                    toggleBlockVisible(c);
                    d->moveCursorVisible(false);
                }
            } else if (d->m_marksVisible && e->pos().x() > markWidth) {
                QTextCursor selection = cursor;
                selection.setVisualNavigation(true);
                d->extraAreaSelectionAnchorBlockNumber = selection.blockNumber();
                selection.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
                selection.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor);
                setTextCursor(selection);
            } else {
                d->extraAreaToggleMarkBlockNumber = cursor.blockNumber();
            }
        } else if (d->m_marksVisible && e->button() == Qt::RightButton) {
            QMenu * contextMenu = new QMenu(this);
            emit d->m_editable->markContextMenuRequested(editableInterface(), cursor.blockNumber() + 1, contextMenu);
            if (!contextMenu->isEmpty())
                contextMenu->exec(e->globalPos());
            delete contextMenu;
        }
    } else if (d->extraAreaSelectionAnchorBlockNumber >= 0) {
        QTextCursor selection = cursor;
        selection.setVisualNavigation(true);
        if (e->type() == QEvent::MouseMove) {
            QTextBlock anchorBlock = document()->findBlockByNumber(d->extraAreaSelectionAnchorBlockNumber);
            selection.setPosition(anchorBlock.position());
            if (cursor.blockNumber() < d->extraAreaSelectionAnchorBlockNumber) {
                selection.movePosition(QTextCursor::EndOfBlock);
                selection.movePosition(QTextCursor::Right);
            }
            selection.setPosition(cursor.block().position(), QTextCursor::KeepAnchor);
            if (cursor.blockNumber() >= d->extraAreaSelectionAnchorBlockNumber) {
                selection.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
                selection.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor);
            }

            if (e->pos().y() >= 0 && e->pos().y() <= d->m_extraArea->height())
                d->autoScrollTimer.stop();
            else if (!d->autoScrollTimer.isActive())
                d->autoScrollTimer.start(100, this);

        } else {
            d->autoScrollTimer.stop();
            d->extraAreaSelectionAnchorBlockNumber = -1;
            return;
        }
        setTextCursor(selection);
    } else if (d->extraAreaToggleMarkBlockNumber >= 0 && d->m_marksVisible && d->m_requestMarkEnabled) {
        if (e->type() == QEvent::MouseButtonRelease && e->button() == Qt::LeftButton) {
            int n = d->extraAreaToggleMarkBlockNumber;
            d->extraAreaToggleMarkBlockNumber = -1;
            if (cursor.blockNumber() == n) {
                int line = n + 1;
                emit d->m_editable->markRequested(editableInterface(), line);
            }
        }
    }
}

QTextBlock TextBlockUserData::testCollapse(const QTextBlock& block)
{
    QTextBlock info = block;
    if (block.userData() && static_cast<TextBlockUserData*>(block.userData())->collapseMode() == CollapseAfter)
        ;
    else if (block.next().userData()
             && static_cast<TextBlockUserData*>(block.next().userData())->collapseMode()
             == TextBlockUserData::CollapseThis)
        info = block.next();
    else
        return QTextBlock();
    int pos = static_cast<TextBlockUserData*>(info.userData())->collapseAtPos();
    if (pos < 0)
        return QTextBlock();
    QTextCursor cursor(info);
    cursor.setPosition(cursor.position() + pos);
    matchCursorForward(&cursor);
    return cursor.block();
}

void TextBlockUserData::doCollapse(const QTextBlock& block, bool visible)
{
    QTextBlock info = block;
    if (block.userData() && static_cast<TextBlockUserData*>(block.userData())->collapseMode() == CollapseAfter)
        ;
    else if (block.next().userData()
             && static_cast<TextBlockUserData*>(block.next().userData())->collapseMode()
             == TextBlockUserData::CollapseThis)
        info = block.next();
    else {
        if (visible && !block.next().isVisible()) {
            // no match, at least unfold!
            QTextBlock b = block.next();
            while (b.isValid() && !b.isVisible()) {
                b.setVisible(true);
                b.setLineCount(visible ? qMax(1, b.layout()->lineCount()) : 0);
                b = b.next();
            }
        }
        return;
    }
    int pos = static_cast<TextBlockUserData*>(info.userData())->collapseAtPos();
    if (pos < 0)
        return;
    QTextCursor cursor(info);
    cursor.setPosition(cursor.position() + pos);
    if (matchCursorForward(&cursor) != Match) {
        if (visible) {
            // no match, at least unfold!
            QTextBlock b = block.next();
            while (b.isValid() && !b.isVisible()) {
                b.setVisible(true);
                b.setLineCount(visible ? qMax(1, b.layout()->lineCount()) : 0);
                b = b.next();
            }
        }
        return;
    }

    QTextBlock b = block.next();
    while (b < cursor.block()) {
        b.setVisible(visible);
        b.setLineCount(visible ? qMax(1, b.layout()->lineCount()) : 0);
        if (visible) {
            TextBlockUserData *data = canCollapse(b);
            if (data && data->collapsed()) {
                QTextBlock end =  testCollapse(b);
                if (data->collapseIncludesClosure())
                    end = end.next();
                if (end.isValid()) {
                    b = end;
                    continue;
                }
            }
        }
        b = b.next();
    }

    bool collapseIncludesClosure = hasClosingCollapseAtEnd(b);
    if (collapseIncludesClosure) {
        b.setVisible(visible);
        b.setLineCount(visible ? qMax(1, b.layout()->lineCount()) : 0);
    }
    static_cast<TextBlockUserData*>(info.userData())->setCollapseIncludesClosure(collapseIncludesClosure);
    static_cast<TextBlockUserData*>(info.userData())->setCollapsed(!block.next().isVisible());

}


void BaseTextEditor::ensureCursorVisible()
{
    QTextBlock block = textCursor().block();
    if (!block.isVisible()) {
        while (!block.isVisible() && block.previous().isValid())
            block = block.previous();
        toggleBlockVisible(block);
    }
    QPlainTextEdit::ensureCursorVisible();
}

void BaseTextEditor::toggleBlockVisible(const QTextBlock &block)
{
    TextEditDocumentLayout *documentLayout = qobject_cast<TextEditDocumentLayout*>(document()->documentLayout());
    QTC_ASSERT(documentLayout, return);

    bool visible = block.next().isVisible();
    TextBlockUserData::doCollapse(block, !visible);
    documentLayout->requestUpdate();
    documentLayout->emitDocumentSizeChanged();
}