mainwidget.cpp Example File

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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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  #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, SIGNAL(clicked()), this, SLOT(toggleAttached()));
      m_buttonLayout->addWidget(detachLegendButton, 0, 0);

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

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

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

      QPushButton *italicButton = new QPushButton("Toggle italic");
      connect(italicButton, SIGNAL(clicked()), this, SLOT(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, SIGNAL(valueChanged(double)), this, SLOT(updateLegendLayout()));
      connect(m_legendPosY, SIGNAL(valueChanged(double)), this, SLOT(updateLegendLayout()));
      connect(m_legendWidth, SIGNAL(valueChanged(double)), this, SLOT(updateLegendLayout()));
      connect(m_legendHeight, SIGNAL(valueChanged(double)), this, SLOT(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, SIGNAL(valueChanged(double)), this, SLOT(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();
  }