QwtPlotCanvas Class

[CodeFreak]

Hi everyone.
Hope everything is going well.
I'm beginner.
I want to use QwtPlotCanvas to change some features of plot like background color and ... .
I tried to use QwtPlotCanvas as following:


MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QwtPlot *BioPlot = new QwtPlot(this);
setCentralWidget(BioPlot);

QwtPlotCanvas *canvas = new QwtPlotCanvas();
canvas->setFocusIndicator( QwtPlotCanvas::CanvasFocusIndicator );
canvas->setFocusPolicy( Qt::StrongFocus );
canvas->setPalette( Qt::black );
setCanvas( canvas );
...

error: 'setCanvas' was not declared in this scope
setCanvas( canvas );

How can I resolve the error?