custominputhandler.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the Qt Data Visualization 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 "custominputhandler.h"

  #include <QtDataVisualization/Q3DCamera>
  #include <QtCore/qmath.h>

  CustomInputHandler::CustomInputHandler(QAbstract3DGraph *graph, QObject *parent) :
      Q3DInputHandler(parent),
      m_highlight(0),
      m_mousePressed(false),
      m_state(StateNormal),
      m_axisX(0),
      m_axisZ(0),
      m_speedModifier(20.0f)
  {
      // Connect to the item selection signal from graph
      connect(graph, &QAbstract3DGraph::selectedElementChanged, this,
              &CustomInputHandler::handleElementSelected);
  }

  void CustomInputHandler::mousePressEvent(QMouseEvent *event, const QPoint &mousePos)
  {
      if (Qt::LeftButton == event->button()) {
          m_highlight->setVisible(false);
          m_mousePressed = true;
      }
      Q3DInputHandler::mousePressEvent(event, mousePos);
  }

  void CustomInputHandler::wheelEvent(QWheelEvent *event)
  {
      float delta = float(event->delta());

      m_axisXMinValue += delta;
      m_axisXMaxValue -= delta;
      m_axisZMinValue += delta;
      m_axisZMaxValue -= delta;
      checkConstraints();

      float y = (m_axisXMaxValue - m_axisXMinValue) * m_aspectRatio;

      m_axisX->setRange(m_axisXMinValue, m_axisXMaxValue);
      m_axisY->setRange(100.0f, y);
      m_axisZ->setRange(m_axisZMinValue, m_axisZMaxValue);
  }

  void CustomInputHandler::mouseMoveEvent(QMouseEvent *event, const QPoint &mousePos)
  {
      // Check if we're trying to drag axis label
      if (m_mousePressed && m_state != StateNormal) {
          setPreviousInputPos(inputPosition());
          setInputPosition(mousePos);
          handleAxisDragging();
      } else {
          Q3DInputHandler::mouseMoveEvent(event, mousePos);
      }
  }

  void CustomInputHandler::mouseReleaseEvent(QMouseEvent *event, const QPoint &mousePos)
  {
      Q3DInputHandler::mouseReleaseEvent(event, mousePos);
      m_mousePressed = false;
      m_state = StateNormal;
  }

  void CustomInputHandler::handleElementSelected(QAbstract3DGraph::ElementType type)
  {
      switch (type) {
      case QAbstract3DGraph::ElementAxisXLabel:
          m_state = StateDraggingX;
          break;
      case QAbstract3DGraph::ElementAxisZLabel:
          m_state = StateDraggingZ;
          break;
      default:
          m_state = StateNormal;
          break;
      }
  }

  void CustomInputHandler::handleAxisDragging()
  {
      float distance = 0.0f;

      // Get scene orientation from active camera
      float xRotation = scene()->activeCamera()->xRotation();

      // Calculate directional drag multipliers based on rotation
      float xMulX = qCos(qDegreesToRadians(xRotation));
      float xMulY = qSin(qDegreesToRadians(xRotation));
      float zMulX = qSin(qDegreesToRadians(xRotation));
      float zMulY = qCos(qDegreesToRadians(xRotation));

      // Get the drag amount
      QPoint move = inputPosition() - previousInputPos();

      // Adjust axes
      switch (m_state) {
      case StateDraggingX:
          distance = (move.x() * xMulX - move.y() * xMulY) * m_speedModifier;
          m_axisXMinValue -= distance;
          m_axisXMaxValue -= distance;
          if (m_axisXMinValue < m_areaMinValue) {
              float dist = m_axisXMaxValue - m_axisXMinValue;
              m_axisXMinValue = m_areaMinValue;
              m_axisXMaxValue = m_axisXMinValue + dist;
          }
          if (m_axisXMaxValue > m_areaMaxValue) {
              float dist = m_axisXMaxValue - m_axisXMinValue;
              m_axisXMaxValue = m_areaMaxValue;
              m_axisXMinValue = m_axisXMaxValue - dist;
          }
          m_axisX->setRange(m_axisXMinValue, m_axisXMaxValue);
          break;
      case StateDraggingZ:
          distance = (move.x() * zMulX + move.y() * zMulY) * m_speedModifier;
          m_axisZMinValue += distance;
          m_axisZMaxValue += distance;
          if (m_axisZMinValue < m_areaMinValue) {
              float dist = m_axisZMaxValue - m_axisZMinValue;
              m_axisZMinValue = m_areaMinValue;
              m_axisZMaxValue = m_axisZMinValue + dist;
          }
          if (m_axisZMaxValue > m_areaMaxValue) {
              float dist = m_axisZMaxValue - m_axisZMinValue;
              m_axisZMaxValue = m_areaMaxValue;
              m_axisZMinValue = m_axisZMaxValue - dist;
          }
          m_axisZ->setRange(m_axisZMinValue, m_axisZMaxValue);
          break;
      default:
          break;
      }
  }

  void CustomInputHandler::checkConstraints()
  {
      if (m_axisXMinValue < m_areaMinValue)
          m_axisXMinValue = m_areaMinValue;
      if (m_axisXMaxValue > m_areaMaxValue)
          m_axisXMaxValue = m_areaMaxValue;
      // Don't allow too much zoom in
      if ((m_axisXMaxValue - m_axisXMinValue) < m_axisXMinRange) {
          float adjust = (m_axisXMinRange - (m_axisXMaxValue - m_axisXMinValue)) / 2.0f;
          m_axisXMinValue -= adjust;
          m_axisXMaxValue += adjust;
      }

      if (m_axisZMinValue < m_areaMinValue)
          m_axisZMinValue = m_areaMinValue;
      if (m_axisZMaxValue > m_areaMaxValue)
          m_axisZMaxValue = m_areaMaxValue;
      // Don't allow too much zoom in
      if ((m_axisZMaxValue - m_axisZMinValue) < m_axisZMinRange) {
          float adjust = (m_axisZMinRange - (m_axisZMaxValue - m_axisZMinValue)) / 2.0f;
          m_axisZMinValue -= adjust;
          m_axisZMaxValue += adjust;
      }
  }