qtgraphs/src/graphs3d/axis/qlogvalue3daxisformatter.cpp

455 lines
14 KiB
C++

// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#include "qlogvalue3daxisformatter_p.h"
#include "qvalue3daxis_p.h"
#include <QtCore/qmath.h>
#include <qgraphs3dlogging_p.h>
QT_BEGIN_NAMESPACE
/*!
* \class QLogValue3DAxisFormatter
* \inmodule QtGraphs
* \ingroup graphs_3D
* \brief The QLogValue3DAxisFormatter class provides formatting rules for a
* logarithmic value axis.
*
* When a formatter is attached to a value axis, the axis range
* cannot include negative values or the zero.
*
* \sa QValue3DAxisFormatter
*/
/*!
* \qmltype LogValue3DAxisFormatter
* \inqmlmodule QtGraphs
* \ingroup graphs_qml_3D
* \nativetype QLogValue3DAxisFormatter
* \inherits Value3DAxisFormatter
* \brief Provides formatting rules for a logarithmic value axis.
*
* When a formatter is attached to a value axis, the axis range
* cannot include negative values or the zero.
*/
/*!
* \qmlproperty real LogValue3DAxisFormatter::base
*
* The base of the logarithm used to map axis values. If the base is non-zero,
* the parent axis segment count will be ignored when the grid line and label
* positions are calculated. If you want the range to be divided into equal
* segments like a normal value axis, set this property value to zero.
*
* The base has to be zero or a positive value and it cannot be equal to one.
* Defaults to ten.
*
* \sa Value3DAxis::segmentCount
*/
/*!
* \qmlproperty bool LogValue3DAxisFormatter::autoSubGrid
*
* Defines whether sub-grid positions are generated automatically.
*
* If this property value is set to \c true, the parent axis sub-segment count
* is ignored when calculating sub-grid line positions. The sub-grid positions
* are generated automatically according to the \l base property value. The
* number of sub-grid lines is set to the base value minus one, rounded down.
* This property is ignored when the base value is zero.
* Defaults to \c true.
*
* \sa base, Value3DAxis::subSegmentCount
*/
/*!
* \qmlproperty bool LogValue3DAxisFormatter::edgeLabelsVisible
*
* Defines whether the first and last label on the axis are visible.
*
* When the \l base property value is non-zero, the whole axis range is often
* not equally divided into
* segments. The first and last segments are often smaller than the other
* segments. In extreme cases, this can lead to overlapping labels on the first
* and last two grid lines. By setting this property to \c false, you can
* suppress showing the minimum and maximum labels for the axis in cases where
* the segments do not exactly fit the axis. Defaults to \c true.
*
* \sa base, Abstract3DAxis::labels
*/
/*!
\qmlsignal LogValue3DAxisFormatter::baseChanged(real base)
This signal is emitted when the base of the logarithm used to map axis
values changes to \a base.
*/
/*!
\qmlsignal LogValue3DAxisFormatter::autoSubGridChanged(bool enabled)
This signal is emitted when the value that specifies whether sub-grid
positions are generated automatically changes to \a enabled.
*/
/*!
\qmlsignal LogValue3DAxisFormatter::edgeLabelsVisibleChanged(bool enabled)
This signal is emitted when the value that specifies whether to show
the first and last label on the axis changes to \a enabled.
*/
/*!
* \internal
*/
QLogValue3DAxisFormatter::QLogValue3DAxisFormatter(QLogValue3DAxisFormatterPrivate &d,
QObject *parent)
: QValue3DAxisFormatter(d, parent)
{
setAllowNegatives(false);
setAllowZero(false);
}
/*!
* Constructs a new logarithmic value 3D axis formatter with the optional
* parent \a parent.
*/
QLogValue3DAxisFormatter::QLogValue3DAxisFormatter(QObject *parent)
: QValue3DAxisFormatter(*(new QLogValue3DAxisFormatterPrivate()), parent)
{
setAllowNegatives(false);
setAllowZero(false);
}
/*!
* Deletes the logarithmic value 3D axis formatter.
*/
QLogValue3DAxisFormatter::~QLogValue3DAxisFormatter() {}
/*!
* \property QLogValue3DAxisFormatter::base
*
* \brief The base of the logarithm used to map axis values.
*
* If the base is non-zero, the parent axis
* segment count will be ignored when the grid line and label positions are
* calculated. If you want the range to be divided into equal segments like a
* normal value axis, set this property value to zero.
*
* The base has to be zero or a positive value and it cannot be equal to one.
* Defaults to ten.
*
* \sa QValue3DAxis::segmentCount
*/
void QLogValue3DAxisFormatter::setBase(qreal base)
{
Q_D(QLogValue3DAxisFormatter);
if (base < 0.0f || base == 1.0f) {
qCWarning(lcAProperties3D,
"%s the logarithm base must be greater than 0 and not equal to 1, attempted: %.1f",
qUtf8Printable(QLatin1String(__FUNCTION__)), base);
return;
}
if (qFuzzyCompare(d->m_base, base)) {
qCDebug(lcAProperties3D,
"%s Base value is already set to: %.1f",
qUtf8Printable(QLatin1String(__FUNCTION__)), base);
return;
}
d->m_base = base;
markDirty(true);
emit baseChanged(base);
}
qreal QLogValue3DAxisFormatter::base() const
{
Q_D(const QLogValue3DAxisFormatter);
return d->m_base;
}
/*!
* \property QLogValue3DAxisFormatter::autoSubGrid
*
* \brief Whether sub-grid positions are generated automatically.
*
* If this property value is set to \c true, the parent axis sub-segment count
* is ignored when calculating sub-grid line positions. The sub-grid positions
* are generated automatically according to the \l base property value. The
* number of sub-grid lines is set to the base value minus one, rounded down.
* This property is ignored when the base value is zero. Defaults to \c true.
*
* \sa base, QValue3DAxis::subSegmentCount
*/
void QLogValue3DAxisFormatter::setAutoSubGrid(bool enabled)
{
Q_D(QLogValue3DAxisFormatter);
if (d->m_autoSubGrid == enabled) {
qCDebug(lcAProperties3D) << __FUNCTION__
<< "auto subgrid value is already set to:" << enabled;
return;
}
d->m_autoSubGrid = enabled;
markDirty(false);
emit autoSubGridChanged(enabled);
}
bool QLogValue3DAxisFormatter::autoSubGrid() const
{
Q_D(const QLogValue3DAxisFormatter);
return d->m_autoSubGrid;
}
/*!
* \property QLogValue3DAxisFormatter::edgeLabelsVisible
*
* \brief Whether the first and last label on the axis are visible.
*
* When the \l base property value is non-zero, the whole axis range is often
* not equally divided into
* segments. The first and last segments are often smaller than the other
* segments. In extreme cases, this can lead to overlapping labels on the first
* and last two grid lines. By setting this property to \c false, you can
* suppress showing the minimum and maximum labels for the axis in cases where
* the segments do not exactly fit the axis. Defaults to \c true.
*
* \sa base, QAbstract3DAxis::labels
*/
void QLogValue3DAxisFormatter::setEdgeLabelsVisible(bool enabled)
{
Q_D(QLogValue3DAxisFormatter);
if (d->m_edgeLabelsVisible == enabled) {
qCDebug(lcAProperties3D) << __FUNCTION__
<< "edge labels visibility is already set to:" << enabled;
return;
}
d->m_edgeLabelsVisible = enabled;
markDirty(true);
emit edgeLabelsVisibleChanged(enabled);
}
bool QLogValue3DAxisFormatter::edgeLabelsVisible() const
{
Q_D(const QLogValue3DAxisFormatter);
return d->m_edgeLabelsVisible;
}
/*!
* \internal
*/
QValue3DAxisFormatter *QLogValue3DAxisFormatter::createNewInstance() const
{
return new QLogValue3DAxisFormatter();
}
/*!
* \internal
*/
void QLogValue3DAxisFormatter::recalculate()
{
Q_D(QLogValue3DAxisFormatter);
d->recalculate();
}
/*!
* \internal
*/
float QLogValue3DAxisFormatter::positionAt(float value) const
{
Q_D(const QLogValue3DAxisFormatter);
return d->positionAt(value);
}
/*!
* \internal
*/
float QLogValue3DAxisFormatter::valueAt(float position) const
{
Q_D(const QLogValue3DAxisFormatter);
return d->valueAt(position);
}
/*!
* \internal
*/
void QLogValue3DAxisFormatter::populateCopy(QValue3DAxisFormatter &copy)
{
Q_D(QLogValue3DAxisFormatter);
QValue3DAxisFormatter::populateCopy(copy);
d->populateCopy(copy);
}
// QLogValue3DAxisFormatterPrivate
QLogValue3DAxisFormatterPrivate::QLogValue3DAxisFormatterPrivate()
: m_base(10.0)
, m_logMin(0.0)
, m_logMax(0.0)
, m_logRangeNormalizer(0.0)
, m_autoSubGrid(true)
, m_edgeLabelsVisible(true)
, m_evenMinSegment(true)
, m_evenMaxSegment(true)
{}
QLogValue3DAxisFormatterPrivate::~QLogValue3DAxisFormatterPrivate() {}
void QLogValue3DAxisFormatterPrivate::recalculate()
{
Q_Q(QLogValue3DAxisFormatter);
// When doing position/value mappings, base doesn't matter, so just use
// natural logarithm
m_logMin = qLn(qreal(m_min));
m_logMax = qLn(qreal(m_max));
m_logRangeNormalizer = m_logMax - m_logMin;
int subGridCount = m_axis->subSegmentCount() - 1;
int segmentCount = m_axis->segmentCount();
QString labelFormat = m_axis->labelFormat();
qreal segmentStep;
if (m_base > 0.0) {
// Update parent axis segment counts
qreal logMin = qLn(qreal(m_min)) / qLn(m_base);
qreal logMax = qLn(qreal(m_max)) / qLn(m_base);
qreal logRangeNormalizer = logMax - logMin;
qreal minDiff = qCeil(logMin) - logMin;
qreal maxDiff = logMax - qFloor(logMax);
m_evenMinSegment = qFuzzyCompare(qreal(0.0), minDiff);
m_evenMaxSegment = qFuzzyCompare(qreal(0.0), maxDiff);
segmentCount = qRound(logRangeNormalizer - minDiff - maxDiff);
if (!m_evenMinSegment)
segmentCount++;
if (!m_evenMaxSegment)
segmentCount++;
segmentStep = 1.0 / logRangeNormalizer;
if (m_autoSubGrid) {
subGridCount = qCeil(m_base) - 2; // -2 for subgrid because subsegment count is base - 1
if (subGridCount < 0)
subGridCount = 0;
}
m_gridPositions.resize(segmentCount + 1);
m_subGridPositions.resize(segmentCount * subGridCount);
m_labelPositions.resize(segmentCount + 1);
m_labelStrings.clear();
m_labelStrings.reserve(segmentCount + 1);
// Calculate segment positions
int index = 0;
if (!m_evenMinSegment) {
m_gridPositions[0] = 0.0f;
m_labelPositions[0] = 0.0f;
if (m_edgeLabelsVisible)
m_labelStrings << q->stringForValue(qreal(m_min), labelFormat);
else
m_labelStrings << hiddenLabelTag;
index++;
}
for (int i = 0; i < segmentCount; i++) {
float gridValue = float((minDiff + qreal(i)) / qreal(logRangeNormalizer));
m_gridPositions[index] = gridValue;
m_labelPositions[index] = gridValue;
if (i != 0 || m_edgeLabelsVisible) {
m_labelStrings << q->stringForValue(qPow(m_base, minDiff + qreal(i) + logMin),
labelFormat);
} else {
m_labelStrings << hiddenLabelTag;
}
index++;
}
// Ensure max value doesn't suffer from any rounding errors
m_gridPositions[segmentCount] = 1.0f;
m_labelPositions[segmentCount] = 1.0f;
QString finalLabel = hiddenLabelTag;
if (m_edgeLabelsVisible || m_evenMaxSegment)
finalLabel = q->stringForValue(qreal(m_max), labelFormat);
if (m_labelStrings.size() > segmentCount)
m_labelStrings.replace(segmentCount, finalLabel);
else
m_labelStrings << finalLabel;
} else {
// Grid lines and label positions are the same as the parent class, so call
// parent impl first to populate those
QValue3DAxisFormatterPrivate::doRecalculate();
// Label string list needs to be repopulated
segmentStep = 1.0 / qreal(segmentCount);
m_labelStrings << q->stringForValue(qreal(m_min), labelFormat);
for (int i = 1; i < m_labelPositions.size() - 1; i++)
m_labelStrings[i] = q->stringForValue(qExp(segmentStep * qreal(i) * m_logRangeNormalizer
+ m_logMin),
labelFormat);
m_labelStrings << q->stringForValue(qreal(m_max), labelFormat);
m_evenMaxSegment = true;
m_evenMinSegment = true;
}
// Subgrid line positions are logarithmically spaced
if (subGridCount > 0) {
float oneSegmentRange = valueAt(float(segmentStep)) - m_min;
float subSegmentStep = oneSegmentRange / float(subGridCount + 1);
// Since the logarithm has the same curvature across whole axis range, we
// can just calculate subgrid positions for the first segment and replicate
// them to other segments.
QList<float> actualSubSegmentSteps(subGridCount);
for (int i = 0; i < subGridCount; i++) {
float currentSubPosition = positionAt(m_min + ((i + 1) * subSegmentStep));
actualSubSegmentSteps[i] = currentSubPosition;
}
float firstPartialSegmentAdjustment = float(segmentStep) - m_gridPositions.at(1);
for (int i = 0; i < segmentCount; i++) {
for (int j = 0; j < subGridCount; j++) {
float position = m_gridPositions.at(i) + actualSubSegmentSteps.at(j);
if (!m_evenMinSegment && i == 0)
position -= firstPartialSegmentAdjustment;
if (position > 1.0f)
position = 1.0f;
if (position < 0.0f)
position = 0.0f;
m_subGridPositions[i * subGridCount + j] = position;
}
}
}
}
void QLogValue3DAxisFormatterPrivate::populateCopy(QValue3DAxisFormatter &copy) const
{
QLogValue3DAxisFormatter *logFormatter = static_cast<QLogValue3DAxisFormatter *>(&copy);
QLogValue3DAxisFormatterPrivate *priv = logFormatter->d_func();
priv->m_base = m_base;
priv->m_logMin = m_logMin;
priv->m_logMax = m_logMax;
priv->m_logRangeNormalizer = m_logRangeNormalizer;
}
float QLogValue3DAxisFormatterPrivate::positionAt(float value) const
{
qreal logValue = qLn(qreal(value));
float retval = float((logValue - m_logMin) / m_logRangeNormalizer);
return retval;
}
float QLogValue3DAxisFormatterPrivate::valueAt(float position) const
{
qreal logValue = (qreal(position) * m_logRangeNormalizer) + m_logMin;
return float(qExp(logValue));
}
QT_END_NAMESPACE