Qt Charts: StackedBarSeries with DateTimeAxis

markugra

Hi there,

I was wondering if anyone has ever tried to plot a (Stacked)BarSeries with a DateTimeAxis as x-axis?
Basically I would like to have something like an AreaSeries over time but with a bar for each time point (each day in my case) also allowing for missing days.
Starting from the qmlchart example I tried the following (View7.qml):

import QtQuick 2.0
import QtCharts 2.0

Item {
    anchors.fill: parent

    //![1]
    ChartView {
        title: "Stacked Bar series"
        anchors.fill: parent
        legend.alignment: Qt.AlignBottom
        antialiasing: true

        StackedBarSeries {
            id: mySeries
            ValueAxis{
                id: valuesID
                min:0
                max:4
                Component.onCompleted: {console.log("max:"+ max)}
                tickCount: 6
            }
            DateTimeAxis{
                id: datesID
                tickCount: 6
                max: {
                    var today = new Date()
                    return today
                }
                min: {
                    var daysAgo = new Date()
                    daysAgo.setMinutes( Qt.formatDateTime ( datesID.max, "mm" )  );
                    daysAgo.setHours( Qt.formatDateTime ( datesID.max, "hh" )-24*(datesID.tickCount-1) );
                    return daysAgo
                }
            }
            axisX: datesID //valuesID//BarCategoryAxis { categories: ["2007", "2008", "2009", "2010", "2011", "2012" ] }
            BarSet { label: "Bob"; values: [2, 2, 3, 4, 5, 6] }
            BarSet { label: "Susan"; values: [5, 1, 2, 4, 1, 7] }
            BarSet { label: "James"; values: [3, 5, 8, 13, 5, 8] }
        }
    }
    //![1]
}

However, the chart is empty if I assign mySeries.axisX to datesID. Using the value axis (valuesID) instead, shows the bars at their index position.

I could probably create a BarCategoryAxis with DateTime-Strings and insert a 0 for missing days in the BarSets, but I doubt that this displays nicely when I want to plot many days and therefore only a few ticks with labels on the x-axis.

Does any one have a suggestion?

I would also be open to using other libraries apart from QtCharts (e.g. qCustomPlot, QWT,...), but I want to include the plot in a window together with QtQuick 2 elements which seems to be rather difficult from what I read. But maybe there has been some changes that I am not aware of?

I'd appreciate any comments, thanks!