text: /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the Qt Charts module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:GPL$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU
  ** General Public License version 3 or (at your option) any later version
  ** approved by the KDE Free Qt Foundation. The licenses are as published by
  ** the Free Software Foundation and appearing in the file LICENSE.GPL3
  ** included in the packaging of this file. Please review the following
  ** information to ensure the GNU General Public License requirements will
  ** be met: https://www.gnu.org/licenses/gpl-3.0.html.
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #include <private/chartdatetimeaxisy_p.h>
  #include <private/chartpresenter_p.h>
  #include <QtCharts/QDateTimeAxis>
  #include <private/abstractchartlayout_p.h>
  #include <QtWidgets/QGraphicsLayout>
  #include <QtCore/QDateTime>
  #include <QtCore/QtMath>
  
  QT_CHARTS_BEGIN_NAMESPACE
  
  ChartDateTimeAxisY::ChartDateTimeAxisY(QDateTimeAxis *axis, QGraphicsItem *item)
      : VerticalAxis(axis, item),
        m_axis(axis)
  {
      QObject::connect(m_axis, SIGNAL(tickCountChanged(int)), this, SLOT(handleTickCountChanged(int)));
      QObject::connect(m_axis, SIGNAL(formatChanged(QString)), this, SLOT(handleFormatChanged(QString)));
  }
  
  ChartDateTimeAxisY::~ChartDateTimeAxisY()
  {
  }
  
  QVector<qreal> ChartDateTimeAxisY::calculateLayout() const
  {
      int tickCount = m_axis->tickCount();
  
      Q_ASSERT(tickCount >= 2);
  
      QVector<qreal> points;
      points.resize(tickCount);
      const QRectF &gridRect = gridGeometry();
      const qreal deltaY = gridRect.height() / (qreal(tickCount) - 1.0);
      for (int i = 0; i < tickCount; ++i)
          points[i] =  qreal(i) * -deltaY + gridRect.bottom();
  
      return points;
  }
  
  void ChartDateTimeAxisY::updateGeometry()
  {
      const QVector<qreal> &layout = ChartAxisElement::layout();
      if (layout.isEmpty())
          return;
      setLabels(createDateTimeLabels(min(), max(), layout.size(), m_axis->format()));
      VerticalAxis::updateGeometry();
  }
  
  void ChartDateTimeAxisY::handleTickCountChanged(int tick)
  {
      Q_UNUSED(tick)
      QGraphicsLayoutItem::updateGeometry();
      if (presenter())
          presenter()->layout()->invalidate();
  }
  
  void ChartDateTimeAxisY::handleFormatChanged(const QString &format)
  {
      Q_UNUSED(format);
      QGraphicsLayoutItem::updateGeometry();
      if (presenter())
          presenter()->layout()->invalidate();
  }
  
  QSizeF ChartDateTimeAxisY::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
  {
      Q_UNUSED(constraint)
  
      QSizeF sh;
  
      QSizeF base = VerticalAxis::sizeHint(which, constraint);
      QStringList ticksList = createDateTimeLabels(min(), max(), m_axis->tickCount(), m_axis->format());
      qreal width = 0;
      // Height of vertical axis sizeHint indicates the maximum distance labels can extend past
      // first and last ticks. Base height is irrelevant.
      qreal height = 0;
  
      if (ticksList.empty())
          return sh;
  
      switch (which) {
          case Qt::MinimumSize: {
              QRectF boundingRect = ChartPresenter::textBoundingRect(axis()->labelsFont(),
                                                                     QStringLiteral("..."),
                                                                     axis()->labelsAngle());
              width = boundingRect.width() + labelPadding() + base.width() + 1.0;
              height = boundingRect.height() / 2.0;
              sh = QSizeF(width, height);
              break;
          }
          case Qt::PreferredSize: {
              qreal labelWidth = 0.0;
              qreal firstHeight = -1.0;
              foreach (const QString& s, ticksList) {
                  QRectF rect = ChartPresenter::textBoundingRect(axis()->labelsFont(), s, axis()->labelsAngle());
                  labelWidth = qMax(rect.width(), labelWidth);
                  height = rect.height();
                  if (firstHeight < 0.0)
                      firstHeight = height;
              }
              width = labelWidth + labelPadding() + base.width() + 2.0; //two pixels of tolerance
              height = qMax(height, firstHeight) / 2.0;
              sh = QSizeF(width, height);
              break;
          }
          default:
          break;
      }
  
      return sh;
  }
  
  #include "moc_chartdatetimeaxisy_p.cpp"
  
  QT_CHARTS_END_NAMESPACE
  