Graph Gallery

 // Copyright (C) 2023 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #include "custominputhandler.h"

 #include <QtCore/qmath.h>

 CustomInputHandler::CustomInputHandler(QAbstract3DGraph *graph, QObject *parent)
     : Q3DInputHandler(parent)
 {
     // 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->angleDelta().y());

     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.f, 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::ElementType::AxisXLabel:
         m_state = StateDraggingX;
         break;
     case QAbstract3DGraph::ElementType::AxisZLabel:
         m_state = StateDraggingZ;
         break;
     default:
         m_state = StateNormal;
         break;
     }
 }

 void CustomInputHandler::handleAxisDragging()
 {
     float distance = 0.f;

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

     // 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.f;
         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.f;
         m_axisZMinValue -= adjust;
         m_axisZMaxValue += adjust;
     }
 }