In qt, some attributes such as font outline, font position, font style, font spacing and window background color size are often set for font.
Here is the code to set these properties:

/*mainwindow.cpp*/
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPainter>
#include <QFont>
#include <QLayout>
#include <QTextCodec>

ArrowWidget::ArrowWidget(QWidget *parent)
    : QWidget(parent)
{
    this->setWindowFlags(Qt::FramelessWindowHint);//Remove title block
    this->showMaximized();
    QTextCodec::setCodecForLocale  (QTextCodec::codecForName("utf8"));//Set coding format
    resize(700,300);//Set window size
}

void ArrowWidget::paintEvent(QPaintEvent *event)
{

        int i = 100,j = 180; //str location
        QString str("ABCDE");
        QPainterPath path;
        QPen pen(Qt::black);//Outlined in black
        QPainter painter(this);

        pen.setStyle(Qt::SolidLine);//Contour is solid
        pen.setWidth(3);//Set font outline line thickness
        QFont font("Times New Roman", 100);//Set font style
        font.setLetterSpacing(QFont::PercentageSpacing,-2); //Set word spacing default 100%
        font.setLetterSpacing(QFont::AbsoluteSpacing,-4); //Default 1

        font.setBold(true);//Set bold
        path.addText(i, j, font, str);//add path
        painter.strokePath(path, pen);//set SolidLine style
        painter.fillPath(path, QBrush(Qt::white));//Font color
        painter.drawPath(path);

}

/*main.cpp*/
#include "mainwindow.h"
#include <QApplication>
#include"qpainter.h"
#include <QPalette>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    ArrowWidget w;
    //Set the background color to red
    QPalette palette(w.palette());
    palette.setColor(QPalette::Background, Qt::red);
    w.setPalette(palette);

    w.show();
    return a.exec();
}

After the code is finally compiled, it should be migrated to the development board. If you want to hide the mouse icon and add the following parameters:
For example, after I compile the code, I generate the executable file as follows:

untitled8 -qws --nomouse

Download full project address:
http://download.csdn.net/download/yang_quan_yang/10159005