Dots in complex window mask

Hi all!

I need to create transparent window with non-transparent text on it. Text is changing dynamically, so I create QPixmap object for mask every time i get new text.
When I set window mask, besides text on screen appear strange dots (attached screenshot). I saw this effect on Linux (Qt 4.6.2) and Windows (Qt 4.6.0).
I tried to save mask as png file, and it was correct, without dots.
Have anyone ideas how to fix it? Or is it a Qt bug?

simplified paint event for my widget:

Code:

---

void Widget::paintEvent(QPaintEvent *)
{
    QPixmap mask;
    mask = QPixmap(800, 600);
    QString text[16][32];
    QPainter maskPainter(&mask);
    maskPainter.setBrush(Qt::black);
    maskPainter.setPen(Qt::black);
    maskPainter.fillRect(-1,-1, mask.width()+1, mask.height()+1, Qt::white);
    maskPainter.setFont(QFont("Liberation Sans", 21, QFont::Bold));
    for (int i = 0; i < 16; i++)
    {
        text[i][0] = "X";
        text[i][31] = "X";
    }
    for (int j = 0; j < 32; j++)
    {
        text[0][j] = "X";
        text[15][j] = "X";
    }
    for (int i = 0; i < 16; i++)
    {
        for (int j = 0; j < 32; j++)
        {
            maskPainter.drawText(800*j/32,600*i/16,800/32,600/16, Qt::AlignBottom|Qt::AlignCenter, text[i][j]);
        }
    }
    resize(mask.width(), mask.height());
    clearMask();
    setMask(mask);
}

---

Thanks.

Does your window have a QSizeGrip by default, or you added one maybe ? It really looks like a sizeGrip

I solved this problem by using QBitmap instead of QPixmap:) It works correct now.