How can i remove qchart unuseful area?

bossman48

Hi,
I am beginner in Qt. Firstly, I want to build a line chart which starts from first pixel of QFrame , end last pixel of QFrame. I attached a picture. In this picture, how i can remove the area which is described with red arrows.

Secondly, i want to add a axis for chart. the axis normally goes to 0,....,n(left to right). but i want to build an axis start right to left. i am using the negative point of the QLineSeries. Is it ok? Do you know any solution except mine?

Finally, in my x axis, i want to seperate a fixed value. In other words, the x axis is have 800 point in every time. If i add 2 point to series, it display 2 point on 800 point. If i add 500 point to series, it display 500 point on 800 point. It may be not clear, because of that i attached a picture. I am send the code which i am working on. Could you help me? Thank you :)

Code:

void MainWindow::lineChart(QFrame *horizontalFrame){

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

//try some example datas
QLineSeries *series = new QLineSeries();
series->setPen(pen);
series->append(0,1);
series->append(-1,4);

//set x axis parameters
QValueAxis* axisX = new QValueAxis();
axisX->setRange(-100,0);
axisX->setLabelsVisible(false);
axisX->setGridLineVisible(false);
axisX->setLineVisible(false);
axisX->setShadesVisible(false);
axisX->setMinorGridLineVisible(false);

//create chart with attributes
QChart *chart = new QChart();
chart->addAxis(axisX,Qt::AlignBottom);
series->attachAxis(axisX);
chart->setBackgroundBrush(Qt::white);
chart->layout()->setContentsMargins(0, 0, 0, 0);
chart->setBackgroundRoundness(0);
chart->setMaximumSize(810,100);
chart->setMinimumSize(810,100);
chart->setPreferredSize(810,100);
chart->addSeries(series);
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);

}

Christian Ehrlicher

Take a look at QChart::margins()

bossman48

@Christian-Ehrlicher Thank you :) How can split x axis to 800 fixed point? Do you know anything about this subject? Thank you again :)

Christian Ehrlicher

QChart is a QGraphicsWidget so https://doc.qt.io/qt-5/qgraphicswidget.html#size-prop maybe?

bossman48

@Christian-Ehrlicher Thank you for quick reply, i have tried but not working :( 2 data point completely envelop the chart like previously.
Thank you so much :)