QT基础 QChart绘制折线

目录

 

1.简单折线

 2.数学折线

3.可滑动折线

---

 

1.简单折线

//![1]
//! 折现段坐标
    QLineSeries *series = new QLineSeries();
//![1]

//![2]
//! 添加点
    series->append(0, 6);
    series->append(2, 4);
    series->append(3, 8);
    series->append(7, 4);
    series->append(10, 5);
    *series << QPointF(11, 1) << QPointF(13, 3) << QPointF(17, 6) << QPointF(18, 3) << QPointF(20, 2);
//![2]

//![3]
    QChart *chart = new QChart();
    chart->legend()->hide();
    chart->addSeries(series);
    //根据已添加到图表中的系列为图表创建轴。以前添加到图表中的任何轴都将被删除
    chart->createDefaultAxes();
    chart->setTitle("Simple line chart example");
//![3]

//![4]
    QChartView *chartView = new QChartView(chart);
    chartView->setRenderHint(QPainter::Antialiasing);
//![4]

 2.数学折线

 QChartView* cview = new QChartView(this);
    cview->setRenderHints(QPainter::Antialiasing);
    QChart* chart = new QChart();
    chart->setTitle("Simple line");

    cview->setChart(chart);
    setCentralWidget(cview);

    QLineSeries* seriesS = new QLineSeries;
    QLineSeries* seriesC = new QLineSeries;
    seriesS->setName("Sinθ");
    seriesC->setName("Cosθ");
    chart->addSeries(seriesS);
    chart->addSeries(seriesC);

    //添加数据绘制
   qreal y0,y1,t=0,intv=0.1;
   size_t count=100;
   for (size_t i=0;iappend(t,y0);
       seriesC->append(t,y1);
       t += intv;
   }

   QValueAxis* axixX = new QValueAxis;
   axixX->setRange(0,10);
   chart->setAxisX(axixX,seriesS);
   chart->setAxisX(axixX,seriesC);

   QValueAxis* axixY = new QValueAxis;
   axixY->setRange(-2,1);
   chart->setAxisY(axixY,seriesS);
   chart->setAxisY(axixY,seriesC);

3.可滑动折线

本质逻辑上与上面差不多，但是如果要放大/缩小等操作，需要重写一下QChartView函数，如果是触摸的需要重写QChart的bool sceneEvent(QEvent *event);

    bool viewportEvent(QEvent *event);
    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);
    void keyPressEvent(QKeyEvent *event);

chart.h

/****************************************************************************
**
** 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.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef CHART_H
#define CHART_H

#include 

QT_BEGIN_NAMESPACE
class QGestureEvent;
QT_END_NAMESPACE

QT_CHARTS_USE_NAMESPACE

//![1]
class Chart : public QChart
//![1]
{
public:
    explicit Chart(QGraphicsItem *parent = 0, Qt::WindowFlags wFlags = 0);
    ~Chart();

protected:
    bool sceneEvent(QEvent *event);

private:
    bool gestureEvent(QGestureEvent *event);

private:

};

#endif // CHART_H

chart.cpp

/****************************************************************************
**
** 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 "chart.h"
#include 
#include 
#include 

Chart::Chart(QGraphicsItem *parent, Qt::WindowFlags wFlags)
    : QChart(QChart::ChartTypeCartesian, parent, wFlags)
{
    // Seems that QGraphicsView (QChartView) does not grab gestures.
    // They can only be grabbed here in the QGraphicsWidget (QChart).
    grabGesture(Qt::PanGesture);
    grabGesture(Qt::PinchGesture);
}

Chart::~Chart()
{

}

//![1]
bool Chart::sceneEvent(QEvent *event)
{
    if (event->type() == QEvent::Gesture)
        return gestureEvent(static_cast(event));
    return QChart::event(event);
}

bool Chart::gestureEvent(QGestureEvent *event)
{
    if (QGesture *gesture = event->gesture(Qt::PanGesture)) {
        QPanGesture *pan = static_cast(gesture);
        QChart::scroll(-(pan->delta().x()), pan->delta().y());
    }

    if (QGesture *gesture = event->gesture(Qt::PinchGesture)) {
        QPinchGesture *pinch = static_cast(gesture);
        if (pinch->changeFlags() & QPinchGesture::ScaleFactorChanged)
            QChart::zoom(pinch->scaleFactor());
    }

    return true;
}
//![1]

chartview.h

/****************************************************************************
**
** 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.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef CHARTVIEW_H
#define CHARTVIEW_H

#include 
#include 

QT_CHARTS_USE_NAMESPACE

//![1]
class ChartView : public QChartView
//![1]
{
public:
    ChartView(QChart *chart, QWidget *parent = 0);

//![2]
protected:
    bool viewportEvent(QEvent *event);
    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);
    void keyPressEvent(QKeyEvent *event);
//![2]

private:
    bool m_isTouching;
};

#endif

chartview.cpp 

/****************************************************************************
**
** 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 "chartview.h"
#include 

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

bool ChartView::viewportEvent(QEvent *event)
{
    if (event->type() == QEvent::TouchBegin) {
        // 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 (m_isTouching)
        return;
    QChartView::mousePressEvent(event);
}

void ChartView::mouseMoveEvent(QMouseEvent *event)
{
    if (m_isTouching)
        return;
    QChartView::mouseMoveEvent(event);
}

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

    // Because we disabled animations when touch event was detected
    // we must put them back on.
    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]
    case Qt::Key_Left:
        chart()->scroll(-10, 0);
        break;
    case Qt::Key_Right:
        chart()->scroll(10, 0);
        break;
    case Qt::Key_Up:
        chart()->scroll(0, 10);
        break;
    case Qt::Key_Down:
        chart()->scroll(0, -10);
        break;
    default:
        QGraphicsView::keyPressEvent(event);
        break;
    }
}

main.cpp

/****************************************************************************
**
** 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 "chart.h"
#include "chartview.h"
#include 
#include 
#include 
#include 
#include 
#include 

QT_CHARTS_USE_NAMESPACE

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

//![1]
    QLineSeries *series = new QLineSeries();
    for (int i = 0; i < 500; i++) {
        QPointF p((qreal) i, qSin(M_PI / 50 * i) * 100);
        p.ry() += QRandomGenerator::global()->bounded(20);
        *series << p;
    }
//![1]

    Chart *chart = new Chart();
    chart->addSeries(series);
    chart->setTitle("Zoom in/out example");
    chart->setAnimationOptions(QChart::SeriesAnimations);
    chart->legend()->hide();
    chart->createDefaultAxes();

    ChartView *chartView = new ChartView(chart);
    chartView->setRenderHint(QPainter::Antialiasing);

    QMainWindow window;
    window.setCentralWidget(chartView);
    window.resize(400, 300);
    window.grabGesture(Qt::PanGesture);
    window.grabGesture(Qt::PinchGesture);
    window.show();

    return a.exec();
}