mainwidget.cpp Example File

legend/mainwidget.cpp
/****************************************************************************
**
** 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.
**
** $QT_BEGIN_LICENSE:GPL$
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** the Free Software Foundation and appearing in the file LICENSE.GPL3
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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();
}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.