Why is width important in tickers (solve)

[houmingc]

code is in this link http://www.qtforum.org/article/26964/how-to-comprehend-this-example.html
i don't understand why width is tested here, why not use a timer?

@
void Ticker::paintEvent(QPaintEvent * /* event */)
{
QPainter painter(this);

int textWidth = fontMetrics().width(text());
if (textWidth < 1)
    return;
int x = -offset;
while (x < width()) {
    painter.drawText(x, 0, textWidth, height(),
                     Qt::AlignLeft | Qt::AlignVCenter, text());
    x += textWidth;
}

@

[edit: added missing coding tags @ SGaist]