Introduce value axis formatter

Currently only used for label formatting.

Also some other preparatory changes for logaxis.

Task-number: QTRD-2787

Note: Not to be merged until 1.0 is released

Change-Id: I2d7ab70b9c51677d0edd5b0226fb779c9e346286
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

1 files changed, 447 insertions, 0 deletions

diff --git a/src/datavisualization/axis/qvalue3daxisformatter.cpp b/src/datavisualization/axis/qvalue3daxisformatter.cpp
new file mode 100644
index 00000000..5f943bd3
--- /dev/null
+++ b/src/datavisualization/axis/qvalue3daxisformatter.cpp
@@ -0,0 +1,447 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc
+** All rights reserved.
+** For any questions to Digia, please use contact form at http://qt.digia.com
+**
+** This file is part of the QtDataVisualization module.
+**
+** Licensees holding valid Qt Enterprise licenses may use this file in
+** accordance with the Qt Enterprise License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://qt.digia.com
+**
+****************************************************************************/
+
+#include "qvalue3daxisformatter_p.h"
+#include "qvalue3daxis_p.h"
+
+QT_BEGIN_NAMESPACE_DATAVISUALIZATION
+
+/*!
+ * \class QValue3DAxisFormatter
+ * \inmodule QtDataVisualization
+ * \brief QValue3DAxisFormatter is base class for value axis formatters.
+ * \since Qt Data Visualization 1.1
+ *
+ * This class provides formatting rules for a linear QValue3DAxis. Subclass it if you
+ * want to implement custom value axes.
+ *
+ * \sa QLog3DAxisFormatter
+ */
+
+/*!
+ * \qmltype ValueAxis3DFormatter
+ * \inqmlmodule QtDataVisualization
+ * \since QtDataVisualization 1.0
+ * \ingroup datavisualization_qml
+ * \instantiates QValue3DAxisFormatter
+ * \brief ValueAxis3DFormatter is base type for value axis formatters.
+ *
+ * This type provides formatting rules for a linear ValueAxis3D.
+ * This type is the default type for ValueAxis3D and thus never needs to be explicitly created.
+ */
+
+/*!
+ * \internal
+ */
+QValue3DAxisFormatter::QValue3DAxisFormatter(QValue3DAxisFormatterPrivate *d, QObject *parent) :
+    QObject(parent),
+    d_ptr(d)
+{
+}
+
+/*!
+ * Constructs a new QValue3DAxisFormatter instance with optional \a parent.
+ */
+QValue3DAxisFormatter::QValue3DAxisFormatter(QObject *parent) :
+    QObject(parent),
+    d_ptr(new QValue3DAxisFormatterPrivate(this))
+{
+}
+
+/*!
+ * Destroys QValue3DAxisFormatter.
+ */
+QValue3DAxisFormatter::~QValue3DAxisFormatter()
+{
+}
+
+/*!
+ * \return \c true if negative values are valid values for parent axis.
+ * The default implementation always returns true.
+ */
+bool QValue3DAxisFormatter::allowNegatives() const
+{
+    return true;
+}
+
+/*!
+ * \return \c true if zero is a valid value for parent axis.
+ * The default implementation always returns true.
+ */
+bool QValue3DAxisFormatter::allowZero() const
+{
+    return true;
+}
+
+/*!
+ * \return the normalized position along the axis for the grid line indicated by the \a index.
+ * The total amount of grid lines is equal to segment count plus one. The returned value should be
+ * between -1.0 (for minimum value) and 1.0 (for maximum value), inclusive.
+ * The grid line at the index zero corresponds to the minimum value of the axis.
+ * This value is used to position the segment grid lines when the graph is rendered.
+ *
+ * \sa doRecalculate(), gridPositions()
+ */
+float QValue3DAxisFormatter::gridPosition(int index)
+{
+    d_ptr->recalculate();
+
+    Q_ASSERT(d_ptr->m_gridPositions.size() > index);
+
+    return d_ptr->m_gridPositions.at(index);
+}
+
+/*!
+ * \return the normalized position along the axis for a subsegment grid line of a segment.
+ * The \a subGridIndex and \a segmentIndex specify the desired subgrid line.
+ * The returned value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive.
+ * The amount of subgrid lines per segment is equal to subsegment count minus one.
+ * This value is used to position the subsegment grid lines when the graph is rendered.
+ *
+ * \sa doRecalculate(), subGridPositions()
+ */
+float QValue3DAxisFormatter::subGridPosition(int subGridIndex, int segmentIndex)
+{
+    d_ptr->recalculate();
+
+    Q_ASSERT(d_ptr->m_subGridPositions.size() > subGridIndex);
+    Q_ASSERT(d_ptr->m_subGridPositions.at(0).size() > segmentIndex);
+
+    return d_ptr->m_subGridPositions.at(segmentIndex).at(subGridIndex);
+}
+
+/*!
+ * \return the normalized position along the axis for given label \a index.
+ * The total amount of labels is equal to segment count plus one. The label \a index zero
+ * corresponds to the minimum value of the axis.
+ * The returned value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive. This value is used to position the axis labels when the graph is rendered.
+ *
+ * \sa doRecalculate(), labelPositions()
+ */
+float QValue3DAxisFormatter::labelPosition(int index)
+{
+    d_ptr->recalculate();
+
+    Q_ASSERT(d_ptr->m_labelPositions.size() > index);
+
+    return d_ptr->m_labelPositions.at(index);
+}
+
+/*!
+ * This method can be used to convert a value to a string using formatter specific formatting
+ * rules supported by the labelFormat property of the parent axis.
+ *
+ * \return the formatted label string using \a value and \a format.
+ *
+ * \sa doRecalculate(), doStringForValue(), QValue3DAxis::labelFormat
+ */
+QString QValue3DAxisFormatter::stringForValue(float value, const QString &format)
+{
+    d_ptr->recalculate();
+    return doStringForValue(value, format);
+}
+
+/*!
+ * \return the normalized position along the axis for the given \a value.
+ * The returned value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive. This value is used to position the items when the graph is rendered.
+ *
+ * \sa doRecalculate(), doPositionAt()
+ */
+float QValue3DAxisFormatter::positionAt(float value)
+{
+    d_ptr->recalculate();
+    return doPositionAt(value);
+}
+
+/*!
+ * \return the value at the normalized \a position along the axis.
+ * The \a position value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive.
+ *
+ * \sa doRecalculate(), doValueAt()
+ */
+float QValue3DAxisFormatter::valueAt(float position)
+{
+    d_ptr->recalculate();
+    return doValueAt(position);
+}
+
+/*!
+ * Creates a new empty instance of this formatter. Must be reimplemented in a subclass.
+ *
+ * \return the new instance. The renderer uses this method to cache a copy of the
+ * the formatter. The ownership of the new copy transfers to the caller.
+ */
+QValue3DAxisFormatter *QValue3DAxisFormatter::createNewInstance()
+{
+    return new QValue3DAxisFormatter();
+}
+
+/*!
+ * Populates the \a copy with the values of this formatter.
+ *
+ * \sa doPopulateCopy()
+ */
+void QValue3DAxisFormatter::populateCopy(QValue3DAxisFormatter &copy)
+{
+    d_ptr->recalculate();
+    doPopulateCopy(copy);
+}
+
+/*!
+ * Marks this formatter dirty, prompting the renderer to make a new copy of its cache on the next
+ * renderer synchronization. Recalculation is also triggered on next access to the values.
+ * This method should be called by a subclass whenever the formatter
+ * is changed in a way that affects the resolved values.
+ */
+void QValue3DAxisFormatter::markDirty()
+{
+    d_ptr->m_needsRecalculate = true;
+    if (d_ptr->m_axis)
+        emit d_ptr->m_axis->dptr()->formatterDirty();
+}
+
+/*!
+ * \return the parent axis. The parent axis must only be accessed in doRecalculate()
+ * method to maintain thread safety in environments using a threaded renderer.
+ *
+ * \sa doRecalculate()
+ */
+QValue3DAxis *QValue3DAxisFormatter::axis() const
+{
+    return d_ptr->m_axis;
+}
+
+/*!
+ * This method populates the label and grid line position arrays, as well as calculates
+ * any values needed for mapping between value and position. It is allowed to access
+ * the parent axis from inside this function.
+ *
+ * This method must be reimplemented in a subclass.
+ *
+ * \sa gridPositions(), subGridPositions(), labelPositions(), axis()
+ */
+void QValue3DAxisFormatter::doRecalculate()
+{
+    d_ptr->doRecalculate();
+}
+
+/*!
+ * Reimplement this method in a subclass to resolve the formatted string for a given \a value
+ * if the default formatting provided by QValue3DAxis::labelFormat property is not sufficient.
+ *
+ * \return the formatted label string using \a value and \a format.
+ *
+ * \sa doRecalculate(), stringForValue(), QValue3DAxis::labelFormat
+ */
+QString QValue3DAxisFormatter::doStringForValue(float value, const QString &format)
+{
+    return d_ptr->stringForValue(value, format);
+}
+
+/*!
+ * Reimplement this method if the position cannot be resolved by linear interpolation
+ * between the parent axis minimum and maximum values.
+ *
+ * \return the normalized position along the axis for the given \a value.
+ * The returned value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive, if the value is within the parent axis range.
+ *
+ * \sa doRecalculate(), positionAt()
+ */
+float QValue3DAxisFormatter::doPositionAt(float value)
+{
+    return d_ptr->positionAt(value);
+}
+
+/*!
+ * Reimplement this method if the value cannot be resolved by linear interpolation
+ * between the parent axis minimum and maximum values.
+ *
+ * \return the value at the normalized \a position along the axis.
+ * The \a position value should be between -1.0 (for minimum value) and 1.0 (for maximum value),
+ * inclusive to obtain values within the parent axis range.
+ *
+ * \sa doRecalculate(), positionAt()
+ */
+float QValue3DAxisFormatter::doValueAt(float position)
+{
+    return d_ptr->valueAt(position);
+}
+
+/*!
+ * Copies all relevant values from this formatter to the \a copy.
+ * When reimplementing this method in a subclass, call the the superclass version at some point.
+ * The renderer uses this method to cache a copy of the the formatter.
+ *
+ * \return the new copy. The ownership of the new copy transfers to the caller.
+ */
+void QValue3DAxisFormatter::doPopulateCopy(QValue3DAxisFormatter &copy)
+{
+    copy.d_ptr->m_min = d_ptr->m_min;
+    copy.d_ptr->m_max = d_ptr->m_max;
+}
+
+/*!
+ * \return Returns a reference to the array of normalized grid positions.
+ * The array size is equal to the segment count of the parent axis plus one.
+ * The grid line at the index zero corresponds to the minimum value of the axis.
+ *
+ * \sa gridPosition()
+ */
+QVector<float> &QValue3DAxisFormatter::gridPositions()
+{
+    return d_ptr->m_gridPositions;
+}
+
+/*!
+ * \return Returns a reference to the array of normalized subgrid positions.
+ * The array size is equal to subsegment count of the parent axis minus one.
+ *
+ * \sa subGridPosition()
+ */
+QVector<QVector<float> > &QValue3DAxisFormatter::subGridPositions()
+{
+    return d_ptr->m_subGridPositions;
+}
+
+/*!
+ * \return Returns a reference to the array of normalized label positions.
+ * The array size is equal to the segment count of the parent axis plus one.
+ *
+ * \sa labelPosition()
+ */
+QVector<float> &QValue3DAxisFormatter::labelPositions()
+{
+    return d_ptr->m_labelPositions;
+}
+
+// QValue3DAxisFormatterPrivate
+QValue3DAxisFormatterPrivate::QValue3DAxisFormatterPrivate(QValue3DAxisFormatter *q)
+    : QObject(0),
+      q_ptr(q),
+      m_needsRecalculate(true),
+      m_min(0.0f),
+      m_max(0.0f),
+      m_rangeNormalizer(0.0f),
+      m_axis(0),
+      m_preparsedParamType(Utils::ParamTypeUnknown)
+{
+}
+
+QValue3DAxisFormatterPrivate::~QValue3DAxisFormatterPrivate()
+{
+}
+
+void QValue3DAxisFormatterPrivate::recalculate()
+{
+    // Only recalculate if we need to and have m_axis pointer. If we do not have
+    // m_axis, either we are not attached to an axis or this is a renderer cache.
+    if (m_axis && m_needsRecalculate)
+        q_ptr->doRecalculate();
+}
+
+void QValue3DAxisFormatterPrivate::doRecalculate()
+{
+    m_needsRecalculate = false;
+
+    m_gridPositions.clear();
+    m_subGridPositions.clear();
+    m_labelPositions.clear();
+
+    int segmentCount = m_axis->segmentCount();
+    int subGridCount = m_axis->subSegmentCount() - 1;
+    m_min = m_axis->min();
+    m_max = m_axis->max();
+    m_rangeNormalizer = (m_max - m_min) / 2.0f;
+
+    m_gridPositions.resize(segmentCount + 1);
+
+    float segmentStep = 2.0f / float(segmentCount);
+    float subSegmentStep = 0;
+    if (subGridCount > 0) {
+        subSegmentStep = segmentStep / (subGridCount + 1);
+        m_subGridPositions.resize(segmentCount);
+        for (int i = 0; i < segmentCount; i++)
+            m_subGridPositions[i].resize(subGridCount);
+    }
+
+    m_labelPositions.resize(segmentCount + 1);
+
+    // Calculate positions
+
+    for (int i = 0; i < segmentCount; i++) {
+        float gridValue = -1.0f + segmentStep * i;
+        m_gridPositions[i] = gridValue;
+        m_labelPositions[i] = gridValue;
+        if (m_subGridPositions.size()) {
+            for (int j = 0; j < subGridCount; j++)
+                m_subGridPositions[i][j] = gridValue + subSegmentStep * i;
+        }
+    }
+
+    // Ensure max value doesn't suffer from any rounding errors
+    m_gridPositions[segmentCount] = 1.0f;
+    m_labelPositions[segmentCount] = 1.0f;
+}
+
+QString QValue3DAxisFormatterPrivate::stringForValue(float value, const QString &format)
+{
+    if (m_previousLabelFormat.compare(format)) {
+        // Format string different than the previous one used, reparse it
+        m_previousLabelFormat = format;
+        m_preparsedParamType = Utils::findFormatParamType(format);
+        m_labelFormatArray = format.toUtf8();
+    }
+
+    return Utils::formatLabel(m_labelFormatArray, m_preparsedParamType, value);
+}
+
+float QValue3DAxisFormatterPrivate::positionAt(float value) const
+{
+    return (((value - m_min) / m_rangeNormalizer) - 1.0f);
+}
+
+float QValue3DAxisFormatterPrivate::valueAt(float position) const
+{
+    return (((position + 1.0f) * m_rangeNormalizer) + m_min);
+}
+
+void QValue3DAxisFormatterPrivate::setAxis(QValue3DAxis *axis)
+{
+    Q_ASSERT(axis);
+
+    connect(axis, &QValue3DAxis::segmentCountChanged,
+            this, &QValue3DAxisFormatterPrivate::setNeedsRecalculate);
+    connect(axis, &QValue3DAxis::subSegmentCountChanged,
+            this, &QValue3DAxisFormatterPrivate::setNeedsRecalculate);
+    connect(axis, &QAbstract3DAxis::rangeChanged,
+            this, &QValue3DAxisFormatterPrivate::setNeedsRecalculate);
+
+    m_axis = axis;
+}
+
+void QValue3DAxisFormatterPrivate::setNeedsRecalculate()
+{
+    m_needsRecalculate = true;
+}
+
+QT_END_NAMESPACE_DATAVISUALIZATION