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29
30#include "datasource.h"
31#include <QtCharts/QXYSeries>
32#include <QtCharts/QAreaSeries>
33#include <QtQuick/QQuickView>
34#include <QtQuick/QQuickItem>
35#include <QtCore/QDebug>
36#include <QtCore/QRandomGenerator>
37#include <QtCore/QtMath>
38
39QT_CHARTS_USE_NAMESPACE
40
41Q_DECLARE_METATYPE(QAbstractSeries *)
42Q_DECLARE_METATYPE(QAbstractAxis *)
43
44DataSource::DataSource(QQuickView *appViewer, QObject *parent) :
45 QObject(parent),
46 m_appViewer(appViewer),
47 m_index(-1)
48{
49 qRegisterMetaType<QAbstractSeries*>();
50 qRegisterMetaType<QAbstractAxis*>();
51
52 generateData(type: 0, rowCount: 5, colCount: 1024);
53}
54
55void DataSource::update(QAbstractSeries *series)
56{
57 if (series) {
58 QXYSeries *xySeries = static_cast<QXYSeries *>(series);
59 m_index++;
60 if (m_index > m_data.count() - 1)
61 m_index = 0;
62
63 QVector<QPointF> points = m_data.at(i: m_index);
64 // Use replace instead of clear + append, it's optimized for performance
65 xySeries->replace(points);
66 }
67}
68
69void DataSource::generateData(int type, int rowCount, int colCount)
70{
71 // Remove previous data
72 m_data.clear();
73
74 // Append the new data depending on the type
75 for (int i(0); i < rowCount; i++) {
76 QVector<QPointF> points;
77 points.reserve(asize: colCount);
78 for (int j(0); j < colCount; j++) {
79 qreal x(0);
80 qreal y(0);
81 switch (type) {
82 case 0:
83 // data with sin + random component
84 y = qSin(M_PI / 50 * j) + 0.5 + QRandomGenerator::global()->generateDouble();
85 x = j;
86 break;
87 case 1:
88 // linear data
89 x = j;
90 y = (qreal) i / 10;
91 break;
92 default:
93 // unknown, do nothing
94 break;
95 }
96 points.append(t: QPointF(x, y));
97 }
98 m_data.append(t: points);
99 }
100}
101

source code of qtcharts/examples/charts/qmloscilloscope/datasource.cpp