Russian Qt Forum

void Widget::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing);

    int sizeCell = 15;

    QColor color1 = Qt::gray;
    QColor color2 = Qt::white;

    painter.setPen(Qt::NoPen);

    bool brush = true;

    for(int row = 0; row < width(); row+=sizeCell)
        for(int column = 0; column < height(); column+=sizeCell)
        {
            if(brush)
                painter.setBrush(color1);
            else
                painter.setBrush(color2);

            painter.drawRect(row, column, sizeCell, sizeCell);

            brush = !brush;
        }
}