关于QCharts拖拽框缩放和平移功能的整合问题

[TB boy]

想实现类似matplotlib工具栏功能，点击按钮可切换功能模式。但现在对于平移和拖拽框缩放这两个功能不知道如何整合到QChartView上
 

这是关于平移的代码

#include "chartview.h"
#include <QValueAxis>
#include <QApplication>

ChartView::ChartView(QWidget* parent)
    : QChartView{ parent }
    , prevPoint_{}
    , leftButtonPressed_{}
    , ctrlPressed_{}
    , alreadySaveRange_{}
    , xRange_{}
    , yRange_{}
    , coordItem_{}
{
    //设置橡皮筋拖动模式
    setDragMode(QGraphicsView::RubberBandDrag);
    //关闭鼠标跟踪
    setMouseTracking(false);

}

ChartView::ChartView(QChart *chart, QWidget *parent)
    : ChartView{ parent } // C++11 Delegating constructors
{
    setChart(chart);
}

ChartView::~ChartView()
{
}

void ChartView::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton) {
        if(m_isMoving){
            prevPoint_ = event->pos();
            leftButtonPressed_ = true;
        }
    }
}

void ChartView::mouseMoveEvent(QMouseEvent *event)
{
    if(m_isMoving){
        //创建文本
        if (!coordItem_) {
            coordItem_ = new QGraphicsSimpleTextItem{ chart() };
            coordItem_->setZValue(5);
            coordItem_->setPos(100, 60);
            coordItem_->show();
        }
        const QPoint curPos{ event->pos() };
        //将获取到的点进行准换为可带有小数位的坐标系点位
        const QPointF curVal{ chart()->mapToValue(QPointF(curPos)) };
        coordItem_->setText(QString("X = %1, Y = %2").arg(curVal.x()).arg(curVal.y()));

        if (leftButtonPressed_) {
            const auto offset = curPos - prevPoint_;
            prevPoint_ = curPos;
            if (!alreadySaveRange_) {
                saveAxisRange();
                alreadySaveRange_ = true;
            }
            chart()->scroll(-offset.x(), offset.y());
        }
    }
    else if(m_isTouching){
        return;
    }
}

void ChartView::mouseReleaseEvent(QMouseEvent *event)
{
    leftButtonPressed_ = false;
    if (event->button() == Qt::RightButton) {
        if (alreadySaveRange_) {
            chart()->axisX()->setRange(xRange_[0], xRange_[1]);
            chart()->axisY()->setRange(yRange_[0], yRange_[1]);
        }
    }

}

void ChartView::wheelEvent(QWheelEvent *event)
{
#if (QT_VERSION <= QT_VERSION_CHECK(6,0,0))
    const auto pos  = QPointF(event->pos());
    const auto isZoomIn = event->delta() > 0;
#else
    const auto pos  = event->position();
    const auto isZoomIn = event->angleDelta().y() > 0;
#endif
    const QPointF curVal = chart()->mapToValue(pos);

    if (!alreadySaveRange_) {
        saveAxisRange();
        alreadySaveRange_ = true;
    }

    auto zoom = [](QValueAxis* axis, double centre, bool zoomIn) {
        constexpr auto scaling{ 1.5 };

        const double down = axis->min();
        const double up = axis->max();

        double downOffset{};
        double upOffset{};
        if (zoomIn) {
            downOffset = (centre - down) / scaling;
            upOffset = (up - centre) / scaling;
        }
        else {
            downOffset = (centre - down) * scaling;
            upOffset = (up - centre) * scaling;
        }

        axis->setRange(centre - downOffset, centre + upOffset);
    };

    if (ctrlPressed_) {
        auto axis = qobject_cast<QValueAxis*>(chart()->axisY());
        zoom(axis, curVal.y(), isZoomIn);
    } else {
        auto axis = qobject_cast<QValueAxis*>(chart()->axisX());
        zoom(axis, curVal.x(), isZoomIn);
    }
}

void ChartView::keyPressEvent(QKeyEvent *event)
{
    if (event->key() == Qt::Key_Control)
        ctrlPressed_ = true;
}

void ChartView::keyReleaseEvent(QKeyEvent *event)
{
    if (event->key() == Qt::Key_Control)
        ctrlPressed_ = false;
}

void ChartView::saveAxisRange()
{
    const auto axisX = qobject_cast<QValueAxis*>(chart()->axisX());
    xRange_ = { axisX->min(), axisX->max() };
    const auto axisY = qobject_cast<QValueAxis*>(chart()->axisY());
    yRange_ = { axisY->min(), axisY->max() };
}

 

这是拖拽框缩放的代码
 

#include "chartview.h"

#include <QMouseEvent>
#include <QValueAxis>

ChartView::ChartView(QWidget *parent)
    : QChartView(parent)
{
    setRubberBand(QChartView::RectangleRubberBand);

}

ChartView::ChartView(QChart *chart, QWidget *parent)
    : QChartView(chart, parent)
{
    setRubberBand(QChartView::RectangleRubberBand);
}


bool ChartView::viewportEvent(QEvent *event)
{
    if (event->type() == QEvent::TouchBegin and m_enableTouchInitialization) {
        // By default touch events are converted to mouse events. So
        // after this event we will get a mouse event also but we want
        // to handle touch events as gestures only. So we need this safeguard
        // to block mouse events that are actually generated from touch.

        m_isTouching = true;

        // Turn off animations when handling gestures they
        // will only slow us down.
        chart()->setAnimationOptions(QChart::NoAnimation);
    }
    return QChartView::viewportEvent(event);
}

void ChartView::mousePressEvent(QMouseEvent *event)
{
    if(event->button()==Qt::LeftButton)
    {
        if (m_isTouching){
            return;

        }

    }

    QChartView::mousePressEvent(event);
}

void ChartView::mouseMoveEvent(QMouseEvent *event)
{
    if(event->button()==Qt::LeftButton)
    {
        if (m_isTouching){
            return;
        }

    }

    QChartView::mouseMoveEvent(event);
}

void ChartView::mouseReleaseEvent(QMouseEvent *event)
{
    buttonPress=false;
    if (m_isTouching)
        m_isTouching = false;
    if (m_isMoving)
        m_isMoving = false;

    chart()->setAnimationOptions(QChart::SeriesAnimations);

    QChartView::mouseReleaseEvent(event);
}

//![1]
void ChartView::keyPressEvent(QKeyEvent *event)
{
    switch (event->key()) {
    case Qt::Key_Plus:
        chart()->zoomIn();
        break;
    case Qt::Key_Minus:
        chart()->zoomOut();
        break;
//![1]
    default:
        QGraphicsView::keyPressEvent(event);
        break;
    }
}

###########################################
    setRubberBand(QChartView::NoRubberBand);
    setDragMode(QGraphicsView::RubberBandDrag);
###########################################
    setRubberBand(QChartView::RectangleRubberBand);
    setDragMode(QGraphicsView::NoDrag);

初步想法是设置模式，通过切换模式来实现不同功能，但不起作用，现在初始化为拖拽框缩放功能，点击切换后平移功能无法实现，现在不知道如何能将上述两种功能整合到一块，实现功能切换。
希望大佬们能给予一些建议，感谢各位了！

 

[赵4老师]

自绘是早晚要学会的技能