Line Chart axis fixed range problem

[bossman48]

Hi all,
i want to build a line chart with using qchart. But I have a problem. i draw paint images for understand clearly. You can see before and after images. I want to build a this type line chart. How can i build a chart like images? Do i use any wrong

I am working on this code which is declared in below.

Code:
void MainWindow::ecgLineChart(QFrame *horizontalFrame){

// set pen for series
QPen pen(QRgb(0x00aa00));
pen.setWidth(2);

//try some example datas with edges
QLineSeries *series = new QLineSeries();

//for flow line chart right to left
series->setPen(pen);
series->append(0,1);
series->append(-1,4);
series->append(-2,5);
series->append(-3,2);
series->append(-4,2);
/*not working for us right now

//create chart with attributes
QChart *chart = new QChart();
chart->createDefaultAxes();
chart->addSeries(series);

chart->setBackgroundBrush(Qt::black);
chart->layout()->setContentsMargins(0, 0, 0, 0);
chart->setMargins(QMargins(0, 0, 0, 0));
chart->setBackgroundRoundness(0);
chart->setMaximumSize(810,100);
chart->setMinimumSize(810,100);
chart->setPreferredSize(810,100);
chart->legend()->hide();

//create chartview with some attributes
QChartView *chartview = new QChartView(chart);
chartview->setRenderHint(QPainter::Antialiasing);
chartview->setParent(horizontalFrame);
chartview->setContentsMargins(0,0,0,0);}