Qt 5.7 | Qt Data Visualization | Axis Range Dragging With Labels Example | axesinputhandler.cpp Example File

Qt 5.7.1 Reference Documentation

# axesinputhandler.cpp Example File

draggableaxes/axesinputhandler.cpp

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      #include "axesinputhandler.h"
      #include <QtCore/qmath.h>

      AxesInputHandler::AxesInputHandler(QAbstract3DGraph *graph, QObject *parent) :
          Q3DInputHandler(parent),
          m_mousePressed(false),
          m_state(StateNormal),
          m_axisX(0),
          m_axisZ(0),
          m_axisY(0),
          m_speedModifier(15.0f)
      {
          // Connect to the item selection signal from graph
          connect(graph, &QAbstract3DGraph::selectedElementChanged, this,
                  &AxesInputHandler::handleElementSelected);
      }

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

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

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

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

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

          // 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();

          // Flip the effect of y movement if we're viewing from below
          float yMove = (yRotation < 0) ? -move.y() : move.y();

          // Adjust axes
          switch (m_state) {
          case StateDraggingX:
              distance = (move.x() * xMulX - yMove * xMulY) / m_speedModifier;
              m_axisX->setRange(m_axisX->min() - distance, m_axisX->max() - distance);
              break;
          case StateDraggingZ:
              distance = (move.x() * zMulX + yMove * zMulY) / m_speedModifier;
              m_axisZ->setRange(m_axisZ->min() + distance, m_axisZ->max() + distance);
              break;
          case StateDraggingY:
              distance = move.y() / m_speedModifier; // No need to use adjusted y move here
              m_axisY->setRange(m_axisY->min() + distance, m_axisY->max() + distance);
              break;
          default:
              break;
          }
      }