@moutasdimitris
Not so easy ;)
void Widget::paintEvent(QPaintEvent* ev)
{
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing,true);
QRect rec=rect();
int minWidth=qMin(rec.width(),rec.height())/2;
int thickness=minWidth/6;
rec.adjust(thickness,thickness,-thickness,-thickness);
minWidth=qMin(rec.width(),rec.height())/2;
QConicalGradient gradient(rec.center(),90);
gradient.setColorAt(0,Qt::transparent);
gradient.setColorAt(.5,QColor(25,180,255));
QPainterPath path;
path.addEllipse(rec.center(),minWidth,minWidth);
QPainterPath clipPath;
clipPath.addEllipse(rec.center(),minWidth-thickness,minWidth-thickness);
path=path.subtracted(clipPath);
int segNum=8; // number of segments
int radius=minWidth+1;
int t=thickness/4; // inter segment width
int cx=rec.center().x();
int cy=rec.center().y();
for(int i=0; i<segNum; i++)
{
// calculate inter segment pos
float angle=180.0/segNum*i+90;
float cos1=qCos(qDegreesToRadians(angle));
float sin1=qSin(qDegreesToRadians(angle));
float cos2=qCos(qDegreesToRadians(angle+180));
float sin2=qSin(qDegreesToRadians(angle+180));
float x1=cx+radius*cos1;
float y1=cy-radius*sin1;
float x2=cx+radius*cos2;
float y2=cy-radius*sin2;
QPainterPath line;
line.moveTo(x1-sin1*t,y1-cos1*t);
line.lineTo(x1+sin1*t,y1+cos1*t);
line.lineTo(cx,cy);
line.lineTo(x2-sin2*t,y2-cos2*t);
line.lineTo(x2+sin2*t,y2+cos2*t);
path=path.subtracted(line); // subtract inter segment
//painter.fillPath(line,Qt::white);
}
painter.fillPath(path,gradient);
}
