How to set colors for LineSeries in QtGraphs using C++

BugSleeper

I Wrote a program follow the example (here), and want to study QtGraphs. If QtGraphs will replace QtCharts in future , some efferts are better to be done today.

The problem is just the same,

How to set different colors for each QLineSeries.
How to remove extra lines links the end point of Line n and the first point of Line n+1.

Thanks!

Screen Shot

Codes:

1. pro file

QT       += core gui widgets quickwidgets graphs quick

CONFIG += c++17
SOURCES += \
    main.cpp \
    graphstest.cpp

HEADERS += \
    graphstest.h

FORMS += \
    graphstest.ui

2. main.cpp

#include "graphstest.h"

#include <QApplication>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	graphsTest w;
	w.show();
	return a.exec();
}

3. graphstest.h

#ifndef GRAPHSTEST_H
#define GRAPHSTEST_H

#include <QDateTimeAxis>
#include <QDialog>
#include <QLineSeries>
#include <QValueAxis>
#include <QVector>
QT_BEGIN_NAMESPACE
namespace Ui
{

class graphsTest;

}
QT_END_NAMESPACE

class graphsTest : public QDialog
{
	Q_OBJECT

public:
	graphsTest(QWidget *parent = nullptr);
	~graphsTest();

protected:
	void timerEvent(QTimerEvent *evt) override;
private slots:
	void on_pushButton_add_clicked();
	void on_checkBox_update_clicked();

private:
	Ui::graphsTest *ui;
	QDateTimeAxis *m_ax;
	QValueAxis *m_ay;
	int m_timerEvent;
	QVector<QLineSeries *> m_lineSeries;
};
#endif // GRAPHSTEST_H

4. graphstest.cpp

#include "graphstest.h"
#include <QDateTime>
#include <QDebug>
#include <QQuickItem>
#include "ui_graphstest.h"
graphsTest::graphsTest(QWidget *parent)
	: QDialog(parent)
	, ui(new Ui::graphsTest)
	, m_ax(new QDateTimeAxis(this))
	, m_ay(new QValueAxis(this))
	, m_timerEvent(-1)
{
	ui->setupUi(this);
	QDateTime dtmNow = QDateTime::currentDateTime();
	m_ax->setMin(dtmNow.addDays(-1));
	m_ax->setMax(dtmNow);
	m_ax->setLabelFormat("yyyy\nMM-dd\nHH");
	m_ay->setRange(-100, 100);

	QList<QObject *> seriesList;
	ui->graphsView->setResizeMode(QQuickWidget::SizeRootObjectToView);
	ui->graphsView->setInitialProperties({{"seriesList", QVariant::fromValue(seriesList)},
										  {"axisX", QVariant::fromValue(m_ax)},
										  {"axisY", QVariant::fromValue(m_ay)},
										  {"zoomAreaEnabled", true}});
	ui->graphsView->loadFromModule("QtGraphs", "GraphsView");
}

graphsTest::~graphsTest()
{
	delete ui;
}

void graphsTest::timerEvent(QTimerEvent *evt)
{
	if (evt->timerId() == m_timerEvent)
	{
		QList<QPointF> data;
		QDateTime dtmNow = QDateTime::currentDateTime();
		const int N = m_lineSeries.size();
		for (int n = 0; n < N; ++n)
		{
			for (int i = 0; i < 30; ++i)
			{
				data << QPointF(dtmNow.addSecs(-3600 * 24.0 / 30 * (29 - i)).toMSecsSinceEpoch(),
								(rand() % 500 - 250) / 100.0 + n * 16 - 80);
			}
			m_lineSeries[n]->replace(data);
		}
		m_ax->setMin(dtmNow.addDays(-1));
		m_ax->setMax(dtmNow);
		if (!ui->checkBox_update->isChecked())
		{
			killTimer(m_timerEvent);
			m_timerEvent = -1;
		}
	}
	QDialog::timerEvent(evt);
}

void graphsTest::on_pushButton_add_clicked()
{
	if (m_lineSeries.size() >= 10)
		return;
	//Add to Graph
	QVariant seriesListVariant = ui->graphsView->rootObject()->property("seriesList");
	if (seriesListVariant.canConvert<QQmlListProperty<QObject>>())
	{
		QLineSeries *newLine = new QLineSeries(this);
		newLine->setColor(QColor(rand() % 128, rand() % 128, rand() % 128));
		newLine->setHoverable(true);
		newLine->setName(QString("Testing %1").arg(m_lineSeries.size()));
		connect(newLine,
				&QAbstractSeries::hover,
				[this](const QString &seriesName, QPointF position, QPointF value) -> void {
					ui->lineEdit_msg->setText(QString("%1:%2 %3 = %4 %5")
												  .arg(seriesName)
												  .arg(position.x())
												  .arg(position.y())
												  .arg(value.x())
												  .arg(value.y()));
				});
		//Add
		QQmlListProperty<QObject> prop = seriesListVariant.value<QQmlListProperty<QObject>>();
		prop.append(&prop, newLine);
		m_lineSeries.append(newLine);
		int cnt = prop.count(&prop);
		qDebug() << cnt;
	}
	if (m_timerEvent < 0)
		m_timerEvent = startTimer(500);
}

void graphsTest::on_checkBox_update_clicked()
{
	if (ui->checkBox_update->isChecked())
		m_timerEvent = startTimer(500);
}

5. graphstest.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>graphsTest</class>
 <widget class="QDialog" name="graphsTest">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>579</width>
    <height>332</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>graphsTest</string>
  </property>
  <layout class="QVBoxLayout" name="verticalLayout_2">
   <item>
    <layout class="QHBoxLayout" name="horizontalLayout">
     <item>
      <widget class="QQuickWidget" name="graphsView">
       <property name="resizeMode">
        <enum>QQuickWidget::ResizeMode::SizeRootObjectToView</enum>
       </property>
      </widget>
     </item>
     <item>
      <layout class="QVBoxLayout" name="verticalLayout">
       <property name="sizeConstraint">
        <enum>QLayout::SizeConstraint::SetMaximumSize</enum>
       </property>
       <item>
        <widget class="QPushButton" name="pushButton_add">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
           <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
         <property name="text">
          <string>Add Serials</string>
         </property>
        </widget>
       </item>
       <item>
        <widget class="QCheckBox" name="checkBox_update">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
           <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
         <property name="text">
          <string>Updating</string>
         </property>
        </widget>
       </item>
       <item>
        <spacer name="verticalSpacer">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Fixed" vsizetype="Expanding">
           <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
         <property name="orientation">
          <enum>Qt::Orientation::Vertical</enum>
         </property>
         <property name="sizeHint" stdset="0">
          <size>
           <width>20</width>
           <height>40</height>
          </size>
         </property>
        </spacer>
       </item>
      </layout>
     </item>
    </layout>
   </item>
   <item>
    <widget class="QLineEdit" name="lineEdit_msg">
     <property name="sizePolicy">
      <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
       <horstretch>0</horstretch>
       <verstretch>0</verstretch>
      </sizepolicy>
     </property>
    </widget>
   </item>
  </layout>
 </widget>
 <customwidgets>
  <customwidget>
   <class>QQuickWidget</class>
   <extends>QWidget</extends>
   <header location="global">QtQuickWidgets/QQuickWidget</header>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

BugSleeper

It's my falut. I have mentioned the author of the raw code , too.
图片.png

QList<QPointF> data should be cleared at each time.