qtextdocumentlayout.cpp

奇趣公司比较新的qt/emd版本

    painter->restore();
}

static QFixed flowPosition(const QTextFrame::iterator it)
{
    if (it.atEnd())
        return 0;

    if (it.currentFrame()) {
        return data(it.currentFrame())->position.y;
    } else {
        QTextBlock block = it.currentBlock();
        QTextLayout *layout = block.layout();
        if (layout->lineCount() == 0)
            return QFixed::fromReal(layout->position().y());
        else
            return QFixed::fromReal(layout->position().y() + layout->lineAt(0).y());
    }
}

static QFixed firstChildPos(const QTextFrame *f)
{
    return flowPosition(f->begin());
}

QLayoutStruct QTextDocumentLayoutPrivate::layoutCell(QTextTable *t, const QTextTableCell &cell, QFixed width,
                                                    int layoutFrom, int layoutTo, QTextTableData *td,
                                                    QFixed absoluteTableY, bool withPageBreaks)
{
    Q_Q(QTextDocumentLayout);

    LDEBUG << "layoutCell";
    QLayoutStruct layoutStruct;
    layoutStruct.frame = t;
    layoutStruct.minimumWidth = 0;
    layoutStruct.maximumWidth = QFIXED_MAX;
    layoutStruct.y = 0;
    if (withPageBreaks) {
        layoutStruct.frameY = absoluteTableY + td->rowPositions.at(cell.row()) + td->cellPadding;
    }
    layoutStruct.x_left = 0;
    layoutStruct.x_right = width;
    // we get called with different widths all the time (for example for figuring
    // out the min/max widths), so we always have to do the full layout ;(
    // also when for example in a table layoutFrom/layoutTo affect only one cell,
    // making that one cell grow the available width of the other cells may change
    // (shrink) and therefore when layoutCell gets called for them they have to
    // be re-laid out, even if layoutFrom/layoutTo is not in their range. Hence
    // this line:

    layoutStruct.pageHeight = QFixed::fromReal(q->document()->pageSize().height());
    if (layoutStruct.pageHeight < 0 || !withPageBreaks)
        layoutStruct.pageHeight = QFIXED_MAX;
    const int currentPage = layoutStruct.currentPage();
    layoutStruct.pageTopMargin = td->effectiveTopMargin + td->cellSpacing + td->border + td->cellPadding;
    layoutStruct.pageBottomMargin = td->effectiveBottomMargin + td->cellSpacing + td->border + td->cellPadding;
    layoutStruct.pageBottom = (currentPage + 1) * layoutStruct.pageHeight - layoutStruct.pageBottomMargin;

    layoutStruct.fullLayout = true;

    QFixed pageTop = currentPage * layoutStruct.pageHeight + layoutStruct.pageTopMargin - layoutStruct.frameY;
    layoutStruct.y = qMax(layoutStruct.y, pageTop);

    const QList<QTextFrame *> childFrames = td->childFrameMap.values(cell.row() + cell.column() * t->rows());
    for (int i = 0; i < childFrames.size(); ++i) {
        QTextFrame *frame = childFrames.at(i);
        QTextFrameData *cd = data(frame);
        cd->sizeDirty = true;
    }

    layoutFlow(cell.begin(), &layoutStruct, layoutFrom, layoutTo, width);

    QFixed floatMinWidth;

    // floats that are located inside the text (like inline images) aren't taken into account by
    // layoutFlow with regards to the cell height (layoutStruct->y), so for a safety measure we
    // do that here. For example with <td><img align="right" src="..." />blah</td>
    // when the image happens to be higher than the text
    for (int i = 0; i < childFrames.size(); ++i) {
        QTextFrame *frame = childFrames.at(i);
        QTextFrameData *cd = data(frame);

        if (frame->frameFormat().position() != QTextFrameFormat::InFlow)
            layoutStruct.y = qMax(layoutStruct.y, cd->position.y + cd->size.height);

        floatMinWidth = qMax(floatMinWidth, cd->minimumWidth);
    }

    // constraint the maximumWidth by the minimum width of the fixed size floats, to
    // keep them visible
    layoutStruct.maximumWidth = qMax(layoutStruct.maximumWidth, floatMinWidth);

    // as floats in cells get added to the table's float list but must not affect
    // floats in other cells we must clear the list here.
    data(t)->floats.clear();

//    qDebug() << "layoutCell done";

    return layoutStruct;
}

QRectF QTextDocumentLayoutPrivate::layoutTable(QTextTable *table, int layoutFrom, int layoutTo, QFixed parentY)
{
    LDEBUG << "layoutTable";
    QTextTableData *td = static_cast<QTextTableData *>(data(table));
    Q_ASSERT(td->sizeDirty);
    const int rows = table->rows();
    const int columns = table->columns();

    const QTextTableFormat fmt = table->format();

    td->childFrameMap.clear();
    {
        const QList<QTextFrame *> children = table->childFrames();
        for (int i = 0; i < children.count(); ++i) {
            QTextFrame *frame = children.at(i);
            QTextTableCell cell = table->cellAt(frame->firstPosition());
            td->childFrameMap.insertMulti(cell.row() + cell.column() * rows, frame);
        }
    }

    QVector<QTextLength> columnWidthConstraints = fmt.columnWidthConstraints();
    if (columnWidthConstraints.size() != columns)
        columnWidthConstraints.resize(columns);
    Q_ASSERT(columnWidthConstraints.count() == columns);

    const QFixed cellSpacing = td->cellSpacing = QFixed::fromReal(scaleToDevice(fmt.cellSpacing()));
    td->cellPadding = QFixed::fromReal(scaleToDevice(fmt.cellPadding()));
    const QFixed leftMargin = td->leftMargin + td->border + td->padding;
    const QFixed rightMargin = td->rightMargin + td->border + td->padding;
    const QFixed topMargin = td->topMargin + td->border + td->padding;

    const QFixed absoluteTableY = parentY + td->position.y;

    QFixed totalWidth = td->contentsWidth;
    // two (vertical) borders per cell per column
    totalWidth -= columns * 2 * td->border;
    // inter-cell spacing
    totalWidth -= (columns - 1) * cellSpacing;
    // cell spacing at the left and right hand side
    totalWidth -= 2 * cellSpacing;
    // remember the width used to distribute to percentaged columns
    QFixed initialTotalWidth = totalWidth;

    td->widths.resize(columns);
    td->widths.fill(0);

    td->minWidths.resize(columns);
    // start with a minimum width of 0. totally empty
    // cells of default created tables are invisible otherwise
    // and therefore hardly editable
    td->minWidths.fill(1);

    td->maxWidths.resize(columns);
    td->maxWidths.fill(QFIXED_MAX);

    // calculate minimum and maximum sizes of the columns
    for (int i = 0; i < columns; ++i) {
        for (int row = 0; row < rows; ++row) {
            const QTextTableCell cell = table->cellAt(row, i);
            const int cspan = cell.columnSpan();

            if (cspan > 1 && i != cell.column())
                continue;

            // to figure out the min and the max width lay out the cell at
            // maximum width. otherwise the maxwidth calculation sometimes
            // returns wrong values
            QLayoutStruct layoutStruct = layoutCell(table, cell, QFIXED_MAX, layoutFrom,
                                                    layoutTo, td, absoluteTableY,
                                                    /*withPageBreaks =*/false);

            // distribute the minimum width over all columns the cell spans
            QFixed widthToDistribute = layoutStruct.minimumWidth + 2 * td->cellPadding;
            for (int n = 0; n < cspan; ++n) {
                const int col = i + n;
                QFixed w = widthToDistribute / (cspan - n);
                td->minWidths[col] = qMax(td->minWidths.at(col), w);
                widthToDistribute -= td->minWidths.at(col);
                if (widthToDistribute <= 0)
                    break;
            }

            QFixed maxW = td->maxWidths.at(i);
            if (layoutStruct.maximumWidth != QFIXED_MAX) {
                if (maxW == QFIXED_MAX)
                    maxW = layoutStruct.maximumWidth + 2 * td->cellPadding;
                else
                    maxW = qMax(maxW, layoutStruct.maximumWidth + 2 * td->cellPadding);
            }
            if (maxW == QFIXED_MAX)
                continue;

            widthToDistribute = maxW;
            for (int n = 0; n < cspan; ++n) {
                const int col = i + n;
                QFixed w = widthToDistribute / (cspan - n);
                td->maxWidths[col] = qMax(td->minWidths.at(col), w);
                widthToDistribute -= td->maxWidths.at(col);
                if (widthToDistribute <= 0)
                    break;
            }
        }
    }

    // set fixed values, figure out total percentages used and number of
    // variable length cells. Also assign the minimum width for variable columns.
    QFixed totalPercentage;
    int variableCols = 0;
    for (int i = 0; i < columns; ++i) {
        const QTextLength &length = columnWidthConstraints.at(i);
        if (length.type() == QTextLength::FixedLength) {
            td->minWidths[i] = td->widths[i] = qMax(QFixed::fromReal(length.rawValue()), td->minWidths.at(i));
            totalWidth -= td->widths.at(i);
        } else if (length.type() == QTextLength::PercentageLength) {
            totalPercentage += QFixed::fromReal(length.rawValue());
        } else if (length.type() == QTextLength::VariableLength) {
            variableCols++;

            td->widths[i] = td->minWidths.at(i);
            totalWidth -= td->minWidths.at(i);
        }
    }

    // set percentage values
    {
        QFixed minimumSlack = QFIXED_MAX;
        int colsWithSlack = 0;

        QFixed overhangingPercent;
        const QFixed totalPercentagedWidth = initialTotalWidth * totalPercentage / 100;
        for (int i = 0; i < columns; ++i)
            if (columnWidthConstraints.at(i).type() == QTextLength::PercentageLength) {
                const QFixed allottedPercentage = QFixed::fromReal(columnWidthConstraints.at(i).rawValue());

                const QFixed percentWidth = totalPercentagedWidth * allottedPercentage / totalPercentage;
                if (percentWidth >= td->minWidths.at(i)) {
                    td->widths[i] = percentWidth;

                    if (td->widths.at(i) > td->minWidths.at(i)) {
                        ++colsWithSlack;
                        minimumSlack = qMin(minimumSlack, td->widths.at(i) - td->minWidths.at(i));
                    }
                } else {
                    td->widths[i] = td->minWidths.at(i);
                    QFixed effectivePercentage = td->widths.at(i) * 100 / totalPercentagedWidth;
                    overhangingPercent += effectivePercentage - allottedPercentage;
                }
                totalWidth -= td->widths.at(i);
            }

        // subtract the overhanging percent from columns with slack
        while (colsWithSlack > 0 && overhangingPercent > 0) {
            const QFixed slackToSubtract = qMin(minimumSlack, totalPercentagedWidth * overhangingPercent / (colsWithSlack * totalPercentage));
            overhangingPercent -= (slackToSubtract * colsWithSlack * 100) / totalPercentagedWidth;

            minimumSlack = QFIXED_MAX;
            colsWithSlack = 0;

            for (int i = 0; i < columns; ++i)
                if (columnWidthConstraints.at(i).type() == QTextLength::PercentageLength) {
                    if (td->widths.at(i) > td->minWidths.at(i)) {
                        td->widths[i] -= slackToSubtract;

                        if (td->widths.at(i) > td->minWidths.at(i)) {
                            ++colsWithSlack;
                            minimumSlack = qMin(minimumSlack, td->widths.at(i) - td->minWidths.at(i));
                        }
                    }
                }
        }
    }

    // for variable columns distribute the remaining space
    if (variableCols > 0 && totalWidth > 0) {
        QVarLengthArray<int> columnsWithProperMaxSize;
        for (int i = 0; i < columns; ++i)
            if (columnWidthConstraints.at(i).type() == QTextLength::VariableLength
                && td->maxWidths.at(i) != QFIXED_MAX)
                columnsWithProperMaxSize.append(i);

        QFixed lastTotalWidth = totalWidth;
        while (totalWidth > 0) {
            for (int k = 0; k < columnsWithProperMaxSize.count(); ++k) {
                const int col = columnsWithProperMaxSize[k];
                const int colsLeft = columnsWithProperMaxSize.count() - k;
                const QFixed w = qMin(td->maxWidths.at(col) - td->widths.at(col), totalWidth / colsLeft);
                td->widths[col] += w;
                totalWidth -= w;
            }
            if (totalWidth == lastTotalWidth)
                break;
            lastTotalWidth = totalWidth;
        }

        if (totalWidth > 0
            // don't unnecessarily grow variable length sized tables
            && fmt.width().type() != QTextLength::VariableLength) {
            const QFixed widthPerAnySizedCol = totalWidth / variableCols;
            for (int col = 0; col < columns; ++col) {
                if (columnWidthConstraints.at(col).type() == QTextLength::VariableLength)
                    td->widths[col] += widthPerAnySizedCol;
            }
        }
    }


    td->columnPositions.resize(columns);
    td->columnPositions[0] = leftMargin /*includes table border*/ + cellSpacing + td->border;

    for (int i = 1; i < columns; ++i)
        td->columnPositions[i] = td->columnPositions.at(i-1) + td->widths.at(i-1) + 2 * td->border + cellSpacing;

    td->heights.resize(rows);
    td->heights.fill(0);

    td->rowPositions.resize(rows);
    td->rowPositions[0] = topMargin /*includes table border*/ + cellSpacing + td->border;

    bool haveRowSpannedCells = false;

    // need to keep track of cell heights for vertical alignment
    QVector<QFixed> cellHeights;
    cellHeights.reserve(rows * columns);

    Q_Q(QTextDocumentLayout);
    QFixed pageHeight = QFixed::fromReal(q->document()->pageSize().height());
    if (pageHeight <= 0)
        pageHeight = QFIXED_MAX;

    QVector<QFixed> heightToDistribute;
    heightToDistribute.resize(columns);

    td->headerHeight = 0;
    const int headerRowCount = qMin(table->format().headerRowCount(), rows - 1);
    const QFixed originalTopMargin = td->effectiveTopMargin;
    bool hasDroppedTable = false;

    // now that we have the column w