QGridLayoutRowData Class Reference

#include <qgridlayoutengine_p.h>

Public Functions
void	calculateGeometries (int start, int end, qreal targetSize, qreal *positions, qreal *sizes, qreal *descents, const QGridLayoutBox &totalBox, const QGridLayoutRowInfo &rowInfo)
void	distributeMultiCells (const QGridLayoutRowInfo &rowInfo)
void	dump (int indent=0) const
void	reset (int count)
void	stealBox (int start, int end, int which, qreal *positions, qreal *sizes)
QGridLayoutBox	totalBox (int start, int end) const

Public Variables
QVector< QGridLayoutBox >	boxes
bool	hasIgnoreFlag
QBitArray	ignore
MultiCellMap	multiCellMap
QVector< qreal >	spacings
QVector< int >	stretches

Detailed Description

Definition at line 229 of file qgridlayoutengine_p.h.

Functions

calculateGeometries()

void QGridLayoutRowData::calculateGeometries	(	int	start,
		int	end,
		qreal	targetSize,
		qreal *	positions,
		qreal *	sizes,
		qreal *	descents,
		const QGridLayoutBox &	totalBox,
		const QGridLayoutRowInfo &	rowInfo
	)

Definition at line 204 of file qgridlayoutengine.cpp.

{
    Q_ASSERT(end > start);

    targetSize = qMax(totalBox.q_minimumSize, targetSize);

    int n = end - start;
    QVarLengthArray<qreal> newSizes(n);
    QVarLengthArray<qreal> factors(n);
    qreal sumFactors = 0.0;
    int sumStretches = 0;
    qreal sumAvailable;

    for (int i = 0; i < n; ++i) {
        if (stretches[start + i] > 0)
            sumStretches += stretches[start + i];
    }

    if (targetSize < totalBox.q_preferredSize) {
        stealBox(start, end, MinimumSize, positions, sizes);

        sumAvailable = targetSize - totalBox.q_minimumSize;
        if (sumAvailable > 0.0) {
            qreal sumDesired = totalBox.q_preferredSize - totalBox.q_minimumSize;

            for (int i = 0; i < n; ++i) {
                if (ignore.testBit(start + i)) {
                    factors[i] = 0.0;
                    continue;
                }

                const QGridLayoutBox &box = boxes.at(start + i);
                qreal desired = box.q_preferredSize - box.q_minimumSize;
                factors[i] = growthFactorBelowPreferredSize(desired, sumAvailable, sumDesired);
                sumFactors += factors[i];
            }

            for (int i = 0; i < n; ++i) {
                Q_ASSERT(sumFactors > 0.0);
                qreal delta = sumAvailable * factors[i] / sumFactors;
                newSizes[i] = sizes[i] + delta;
            }
        }
    } else {
        bool isLargerThanMaximum = (targetSize > totalBox.q_maximumSize);
        if (isLargerThanMaximum) {
            stealBox(start, end, MaximumSize, positions, sizes);
            sumAvailable = targetSize - totalBox.q_maximumSize;
        } else {
            stealBox(start, end, PreferredSize, positions, sizes);
            sumAvailable = targetSize - totalBox.q_preferredSize;
        }

        if (sumAvailable > 0.0) {
            qreal sumCurrentAvailable = sumAvailable;
            bool somethingHasAMaximumSize = false;

            qreal sumSizes = 0.0;
            for (int i = 0; i < n; ++i)
                sumSizes += sizes[i];

            for (int i = 0; i < n; ++i) {
                if (ignore.testBit(start + i)) {
                    newSizes[i] = 0.0;
                    factors[i] = 0.0;
                    continue;
                }

                const QGridLayoutBox &box = boxes.at(start + i);
                qreal boxSize;

                qreal desired;
                if (isLargerThanMaximum) {
                    boxSize = box.q_maximumSize;
                    desired = rowInfo.boxes.value(start + i).q_maximumSize - boxSize;
                } else {
                    boxSize = box.q_preferredSize;
                    desired = box.q_maximumSize - boxSize;
                }
                if (desired == 0.0) {
                    newSizes[i] = sizes[i];
                    factors[i] = 0.0;
                } else {
                    Q_ASSERT(desired > 0.0);

                    int stretch = stretches[start + i];
                    if (sumStretches == 0) {
                        if (hasIgnoreFlag) {
                            factors[i] = (stretch < 0) ? qreal(1.0) : qreal(0.0);
                        } else {
                            factors[i] = (stretch < 0) ? sizes[i] : qreal(0.0);
                        }
                    } else if (stretch == sumStretches) {
                        factors[i] = 1.0;
                    } else if (stretch <= 0) {
                        factors[i] = 0.0;
                    } else {
                        qreal ultimateSize;
                        qreal ultimateSumSizes;
                        qreal x = ((stretch * sumSizes)
                                   - (sumStretches * boxSize))
                                  / (sumStretches - stretch);
                        if (x >= 0.0) {
                            ultimateSize = boxSize + x;
                            ultimateSumSizes = sumSizes + x;
                        } else {
                            ultimateSize = boxSize;
                            ultimateSumSizes = (sumStretches * boxSize)
                                                        / stretch;
                        }

                        /*
                            We multiply these by 1.5 to give some space for a smooth transition
                            (at the expense of the stretch factors, which are not fully respected
                            during the transition).
                        */
                        ultimateSize = ultimateSize * 3 / 2;
                        ultimateSumSizes = ultimateSumSizes * 3 / 2;

                        qreal beta = ultimateSumSizes - sumSizes;
                        if (!beta) {
                            factors[i] = 1;
                        } else {
                            qreal alpha = qMin(sumCurrentAvailable, beta);
                            qreal ultimateFactor = (stretch * ultimateSumSizes / sumStretches)
                                                   - (boxSize);
                            qreal transitionalFactor = sumCurrentAvailable * (ultimateSize - boxSize) / beta;

                            factors[i] = ((alpha * ultimateFactor)
                                          + ((beta - alpha) * transitionalFactor)) / beta;
                        }

                    }
                    sumFactors += factors[i];
                    if (desired < sumCurrentAvailable)
                        somethingHasAMaximumSize = true;

                    newSizes[i] = -1.0;
                }
            }

            bool keepGoing = somethingHasAMaximumSize;
            while (keepGoing) {
                keepGoing = false;

                for (int i = 0; i < n; ++i) {
                    if (newSizes[i] >= 0.0)
                        continue;

                    qreal maxBoxSize;
                    if (isLargerThanMaximum)
                        maxBoxSize = rowInfo.boxes.value(start + i).q_maximumSize;
                    else
                        maxBoxSize = boxes.at(start + i).q_maximumSize;

                    qreal avail = sumCurrentAvailable * factors[i] / sumFactors;
                    if (sizes[i] + avail >= maxBoxSize) {
                        newSizes[i] = maxBoxSize;
                        sumCurrentAvailable -= maxBoxSize - sizes[i];
                        sumFactors -= factors[i];
                        keepGoing = (sumCurrentAvailable > 0.0);
                        if (!keepGoing)
                            break;
                    }
                }
            }

            for (int i = 0; i < n; ++i) {
                if (newSizes[i] < 0.0) {
                    qreal delta = (sumFactors == 0.0) ? qreal(0.0)
                                                      : sumCurrentAvailable * factors[i] / sumFactors;
                    newSizes[i] = sizes[i] + delta;
                }
            }
        }
    }

    if (sumAvailable > 0) {
        qreal offset = 0;
        for (int i = 0; i < n; ++i) {
            qreal delta = newSizes[i] - sizes[i];
            positions[i] += offset;
            sizes[i] += delta;
            offset += delta;
        }

#if 0 // some "pixel allocation"
        int surplus = targetSize - (positions[n - 1] + sizes[n - 1]);
        Q_ASSERT(surplus >= 0 && surplus <= n);

        int prevSurplus = -1;
        while (surplus > 0 && surplus != prevSurplus) {
            prevSurplus = surplus;

            int offset = 0;
            for (int i = 0; i < n; ++i) {
                const QGridLayoutBox &box = boxes.at(start + i);
                int delta = (!ignore.testBit(start + i) && surplus > 0
                             && factors[i] > 0 && sizes[i] < box.q_maximumSize)
                    ? 1 : 0;

                positions[i] += offset;
                sizes[i] += delta;
                offset += delta;
                surplus -= delta;
            }
        }
        Q_ASSERT(surplus == 0);
#endif
    }

    if (descents) {
        for (int i = 0; i < n; ++i) {
            if (ignore.testBit(start + i))
                continue;
            const QGridLayoutBox &box = boxes.at(start + i);
            descents[i] = fixedDescent(box.q_minimumDescent, box.q_minimumAscent, sizes[i]);
        }
    }
}

distributeMultiCells()

void QGridLayoutRowData::distributeMultiCells

(

const QGridLayoutRowInfo &

rowInfo

)

Definition at line 169 of file qgridlayoutengine.cpp.

Referenced by QGridLayoutEngine::ensureColumnAndRowData().

{
    MultiCellMap::const_iterator i = multiCellMap.constBegin();
    for (; i != multiCellMap.constEnd(); ++i) {
        int start = i.key().first;
        int span = i.key().second;
        int end = start + span;
        const QGridLayoutBox &box = i.value().q_box;
        int stretch = i.value().q_stretch;

        QGridLayoutBox totalBox = this->totalBox(start, end);
        QVarLengthArray<QGridLayoutBox> extras(span);
        QVarLengthArray<qreal> dummy(span);
        QVarLengthArray<qreal> newSizes(span);

        for (int j = 0; j < NSizes; ++j) {
            qreal extra = compare(box, totalBox, j);
            if (extra > 0.0) {
                calculateGeometries(start, end, box.q_sizes(j), dummy.data(), newSizes.data(),
                                    0, totalBox, rowInfo);

                for (int k = 0; k < span; ++k)
                    extras[k].q_sizes(j) = newSizes[k];
            }
        }

        for (int k = 0; k < span; ++k) {
            boxes[start + k].combine(extras[k]);
            if (stretch != 0)
                stretches[start + k] = qMax(stretches[start + k], stretch);
        }
    }
    multiCellMap.clear();
}

dump()

void QGridLayoutRowData::dump

(

int

indent = 0

)

const

Definition at line 466 of file qgridlayoutengine.cpp.

{
    qDebug("%*sData", indent, "");

    for (int i = 0; i < ignore.count(); ++i) {
        qDebug("%*s Row %d (stretch %d, spacing %g)", indent, "", i, stretches.at(i),
               spacings.at(i));
        if (ignore.testBit(i))
            qDebug("%*s  Ignored", indent, "");
        boxes.at(i).dump(indent + 2);
    }

    MultiCellMap::const_iterator it = multiCellMap.constBegin();
    while (it != multiCellMap.constEnd()) {
        qDebug("%*s Multi-cell entry <%d, %d> (stretch %d)", indent, "", it.key().first,
               it.key().second, it.value().q_stretch);
        it.value().q_box.dump(indent + 2);
    }
}

reset()

void QGridLayoutRowData::reset

(

int

count

)

Definition at line 159 of file qgridlayoutengine.cpp.

Referenced by QGridLayoutEngine::ensureColumnAndRowData().

{
    ignore.fill(false, count);
    boxes.fill(QGridLayoutBox(), count);
    multiCellMap.clear();
    stretches.fill(0, count);
    spacings.fill(0.0, count);
    hasIgnoreFlag = false;
}

stealBox()

void QGridLayoutRowData::stealBox	(	int	start,
		int	end,
		int	which,
		qreal *	positions,
		qreal *	sizes
	)

Definition at line 444 of file qgridlayoutengine.cpp.

{
    qreal offset = 0.0;
    qreal nextSpacing = 0.0;

    for (int i = start; i < end; ++i) {
        qreal avail = 0.0;

        if (!ignore.testBit(i)) {
            const QGridLayoutBox &box = boxes.at(i);
            avail = box.q_sizes(which);
            offset += nextSpacing;
            nextSpacing = spacings.at(i);
        }

        *positions++ = offset;
        *sizes++ = avail;
        offset += avail;
    }
}

totalBox()

QGridLayoutBox QGridLayoutRowData::totalBox	(	int	start,
		int	end
	)		const

Definition at line 428 of file qgridlayoutengine.cpp.

Referenced by QGridLayoutEngine::ensureColumnAndRowData().

{
    QGridLayoutBox result;
    if (start < end) {
        result.q_maximumSize = 0.0;
        qreal nextSpacing = 0.0;
        for (int i = start; i < end; ++i) {
            if (ignore.testBit(i))
                continue;
            result.add(boxes.at(i), stretches.at(i), nextSpacing);
            nextSpacing = spacings.at(i);
        }
    }
    return result;
}

Properties

boxes

QVector<QGridLayoutBox> QGridLayoutRowData::boxes

Definition at line 245 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

hasIgnoreFlag

bool QGridLayoutRowData::hasIgnoreFlag

Definition at line 249 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

ignore

QBitArray QGridLayoutRowData::ignore

Definition at line 244 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

multiCellMap

MultiCellMap QGridLayoutRowData::multiCellMap

Definition at line 246 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

spacings

QVector<qreal> QGridLayoutRowData::spacings

Definition at line 248 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

stretches

QVector<int> QGridLayoutRowData::stretches

Definition at line 247 of file qgridlayoutengine_p.h.

Referenced by QGridLayoutEngine::fillRowData().

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The documentation for this class was generated from the following files:

• /src/gui/graphicsview/qgridlayoutengine_p.h
• /src/gui/graphicsview/qgridlayoutengine.cpp