// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \page qtcharts-boxplotchart-example.html
    \title Creating Box-and-Whiskers Charts
    \brief Shows how to create a box-and-whiskers chart.
    \include gallery.qdocinc

    The example also shows how to read the non-continuous data from a file,
    arrange it and find medians needed for box-and-whiskers plotting.

    \image examples_boxplotchart.png {Screenshot showing box and whisker plots in a chart}

    To show the share deviation of two companies we start by creating two QBoxPlotSeries to handle monthly data.

    \snippet chartsgallery/boxplotwidget.cpp 1

    QFile class is used to open a text file where the non-continuous data is kept. The BoxDataReader is an auxiliary class for
    reading the text file and finding the extreme and median values from the data. The BoxDataReader is explained in more detail later.
    The method readBox reads the values and sets them to the QBoxSet item which the method returns for the caller. The returned QBoxSet
    item is added to the series.

    \snippet chartsgallery/boxplotwidget.cpp 2

    In this section a second file is opened for reading the data for the second company.

    \snippet chartsgallery/boxplotwidget.cpp 3

    In this code snippet a new QChart instance is created and previously created series are added to it. The title is also defined and
    animation is set to be SeriesAnimation.

    \snippet chartsgallery/boxplotwidget.cpp 4

    Here we ask the chart to create default axes for our presentation. We also set the range for the vertical axis by querying the pointer
    for the axis from the chart, and then setting the min and max for that axis.

    \snippet chartsgallery/boxplotwidget.cpp 5

    In this section we set the legends to be visible and place them at the bottom of the chart.

    \snippet chartsgallery/boxplotwidget.cpp 6

    Finally, we add the chart onto a view. We also turn on the antialiasing for the chartView.

    \snippet chartsgallery/boxplotwidget.cpp 7

    The chart is ready to be shown.

    Here the method readBox is explained in detail.

    First, a line is read from the file and lines starting with # are rejected
    since they are considered as comment lines.

    \snippet chartsgallery/boxplotdatareader.cpp 1

    In this file the data is arranged as number, space, number, or space. On this snippet the line is split into single number strings which
    are stored on QStringList.

    \snippet chartsgallery/boxplotdatareader.cpp 2

    The sortedList will hold the numbers in continuous order and in this code segment we show how to do it. First the sortedList is cleared and numbers
    are read from the strList and stored into sortedList in double format. The qSort method arranges the sortedList into continuous order
    starting from the smallest.

    \snippet chartsgallery/boxplotdatareader.cpp 3

    Below you will find a code sample showing how to select extremes and medians from the continuous data. Firstly a new QBoxSet is created.
    Lower and upper extremes are simple to select; they are just first and last items on the sortedList. For medians we use a helper
    method findMedian which is explained later. For the median from the upper half we need to adjust the begin number if the
    amount of the numbers is even or uneven. The end number for lower half comes naturally from int rounding.

    \snippet chartsgallery/boxplotdatareader.cpp 4

    Below you will find the code sample for the method findMedian. If the amount of numbers is uneven we select the number from
    the middle. For even amount numbers we take two numbers from the middle and calculate the mean value.

    \snippet chartsgallery/boxplotdatareader.cpp 5
*/
