mainwidget.cpp Example File | Qt Charts 5.12.8

- Qt 5.12
- Qt Charts
- Legend Example
- mainwidget.cpp Example File
- Qt Charts | Commercial or GPLv3

# mainwidget.cpp Example File

legend/mainwidget.cpp

     /****************************************************************************
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     ** Copyright (C) 2016 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
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     ** This file is part of the Qt Charts module of the Qt Toolkit.
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     ** $QT_BEGIN_LICENSE:GPL$
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     #include "mainwidget.h"
     #include <QtCharts/QChart>
     #include <QtCharts/QChartView>
     #include <QtWidgets/QPushButton>
     #include <QtWidgets/QLabel>
     #include <QtCore/QDebug>
     #include <QtCharts/QBarSet>
     #include <QtCharts/QBarSeries>
     #include <QtCharts/QLegend>
     #include <QtWidgets/QFormLayout>

     QT_CHARTS_USE_NAMESPACE

     MainWidget::MainWidget(QWidget *parent) :
         QWidget(parent)
     {
         // Create buttons for ui
         m_buttonLayout = new QGridLayout();
         QPushButton *detachLegendButton = new QPushButton("Toggle attached");
         connect(detachLegendButton, &QPushButton::clicked, this, &MainWidget::toggleAttached);
         m_buttonLayout->addWidget(detachLegendButton, 0, 0);

         QPushButton *addSetButton = new QPushButton("add barset");
         connect(addSetButton, &QPushButton::clicked, this, &MainWidget::addBarset);
         m_buttonLayout->addWidget(addSetButton, 2, 0);
         QPushButton *removeBarsetButton = new QPushButton("remove barset");
         connect(removeBarsetButton, &QPushButton::clicked, this, &MainWidget::removeBarset);
         m_buttonLayout->addWidget(removeBarsetButton, 3, 0);

         QPushButton *alignButton = new QPushButton("Align (Bottom)");
         connect(alignButton, &QPushButton::clicked, this, &MainWidget::setLegendAlignment);
         m_buttonLayout->addWidget(alignButton, 4, 0);

         QPushButton *boldButton = new QPushButton("Toggle bold");
         connect(boldButton, &QPushButton::clicked, this, &MainWidget::toggleBold);
         m_buttonLayout->addWidget(boldButton, 8, 0);

         QPushButton *italicButton = new QPushButton("Toggle italic");
         connect(italicButton, &QPushButton::clicked, this, &MainWidget::toggleItalic);
         m_buttonLayout->addWidget(italicButton, 9, 0);

         m_legendPosX = new QDoubleSpinBox();
         m_legendPosY = new QDoubleSpinBox();
         m_legendWidth = new QDoubleSpinBox();
         m_legendHeight = new QDoubleSpinBox();

         connect(m_legendPosX,
                 static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged),
                 this, &MainWidget::updateLegendLayout);
         connect(m_legendPosY,
                 static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged),
                 this, &MainWidget::updateLegendLayout);
         connect(m_legendWidth,
                 static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged),
                 this, &MainWidget::updateLegendLayout);
         connect(m_legendHeight,
                 static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged),
                 this, &MainWidget::updateLegendLayout);

         QFormLayout *legendLayout = new QFormLayout();
         legendLayout->addRow("HPos", m_legendPosX);
         legendLayout->addRow("VPos", m_legendPosY);
         legendLayout->addRow("Width", m_legendWidth);
         legendLayout->addRow("Height", m_legendHeight);
         m_legendSettings = new QGroupBox("Detached legend");
         m_legendSettings->setLayout(legendLayout);
         m_buttonLayout->addWidget(m_legendSettings);
         m_legendSettings->setVisible(false);

         // Create chart view with the chart
         m_chart = new QChart();
         m_chartView = new QChartView(m_chart, this);

         // Create spinbox to modify font size
         m_fontSize = new QDoubleSpinBox();
         m_fontSize->setValue(m_chart->legend()->font().pointSizeF());
         connect(m_fontSize,
                 static_cast<void (QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged),
                 this, &MainWidget::fontSizeChanged);

         QFormLayout *fontLayout = new QFormLayout();
         fontLayout->addRow("Legend font size", m_fontSize);

         // Create layout for grid and detached legend
         m_mainLayout = new QGridLayout();
         m_mainLayout->addLayout(m_buttonLayout, 0, 0);
         m_mainLayout->addLayout(fontLayout, 1, 0);
         m_mainLayout->addWidget(m_chartView, 0, 1, 3, 1);
         setLayout(m_mainLayout);

         createSeries();
     }

     void MainWidget::createSeries()
     {
         m_series = new QBarSeries();
         addBarset();
         addBarset();
         addBarset();
         addBarset();

         m_chart->addSeries(m_series);
         m_chart->setTitle("Legend detach example");
         m_chart->createDefaultAxes();
         m_chart->legend()->setVisible(true);
         m_chart->legend()->setAlignment(Qt::AlignBottom);

         m_chartView->setRenderHint(QPainter::Antialiasing);
     }

     void MainWidget::showLegendSpinbox()
     {
         m_legendSettings->setVisible(true);
         QRectF chartViewRect = m_chartView->rect();

         m_legendPosX->setMinimum(0);
         m_legendPosX->setMaximum(chartViewRect.width());
         m_legendPosX->setValue(150);

         m_legendPosY->setMinimum(0);
         m_legendPosY->setMaximum(chartViewRect.height());
         m_legendPosY->setValue(150);

         m_legendWidth->setMinimum(0);
         m_legendWidth->setMaximum(chartViewRect.width());
         m_legendWidth->setValue(150);

         m_legendHeight->setMinimum(0);
         m_legendHeight->setMaximum(chartViewRect.height());
         m_legendHeight->setValue(75);
     }

     void MainWidget::hideLegendSpinbox()
     {
         m_legendSettings->setVisible(false);
     }

     void MainWidget::toggleAttached()
     {
         QLegend *legend = m_chart->legend();
         if (legend->isAttachedToChart()) {
             legend->detachFromChart();
             m_chart->legend()->setBackgroundVisible(true);
             m_chart->legend()->setBrush(QBrush(QColor(128, 128, 128, 128)));
             m_chart->legend()->setPen(QPen(QColor(192, 192, 192, 192)));
             showLegendSpinbox();
             updateLegendLayout();
         } else {
             legend->attachToChart();
             legend->setBackgroundVisible(false);
             hideLegendSpinbox();
         }
         update();
     }

     void MainWidget::addBarset()
     {
         QBarSet *barSet = new QBarSet(QString("set ") + QString::number(m_series->count()));
         qreal delta = m_series->count() * 0.1;
         *barSet << 1 + delta << 2 + delta << 3 + delta << 4 + delta;
         m_series->append(barSet);
     }

     void MainWidget::removeBarset()
     {
         QList<QBarSet *> sets = m_series->barSets();
         if (sets.count() > 0) {
             m_series->remove(sets.at(sets.count() - 1));
         }
     }

     void MainWidget::setLegendAlignment()
     {
         QPushButton *button = qobject_cast<QPushButton *>(sender());

         switch (m_chart->legend()->alignment()) {
         case Qt::AlignTop:
             m_chart->legend()->setAlignment(Qt::AlignLeft);
             if (button)
                 button->setText("Align (Left)");
             break;
         case Qt::AlignLeft:
             m_chart->legend()->setAlignment(Qt::AlignBottom);
             if (button)
                 button->setText("Align (Bottom)");
             break;
         case Qt::AlignBottom:
             m_chart->legend()->setAlignment(Qt::AlignRight);
             if (button)
                 button->setText("Align (Right)");
             break;
         default:
             if (button)
                 button->setText("Align (Top)");
             m_chart->legend()->setAlignment(Qt::AlignTop);
             break;
         }
     }

     void MainWidget::toggleBold()
     {
         QFont font = m_chart->legend()->font();
         font.setBold(!font.bold());
         m_chart->legend()->setFont(font);
     }

     void MainWidget::toggleItalic()
     {
         QFont font = m_chart->legend()->font();
         font.setItalic(!font.italic());
         m_chart->legend()->setFont(font);
     }

     void MainWidget::fontSizeChanged()
     {
         QFont font = m_chart->legend()->font();
         font.setPointSizeF(m_fontSize->value());
         m_chart->legend()->setFont(font);
     }

     void MainWidget::updateLegendLayout()
     {
         m_chart->legend()->setGeometry(QRectF(m_legendPosX->value(),
                                               m_legendPosY->value(),
                                               m_legendWidth->value(),
                                               m_legendHeight->value()));
         m_chart->legend()->update();
     }