Impossible to get correct widget background color

[croscato]

Hi all.

Here is what I want to do:
1) In paintEvent a make some draws and text in the widget using a QPainter object

2) Then a want to give it a perfurated effect. I'm thinking in this solution

QBrush brush(this->palette().background().color(),Qt::Dense4Pattern);
painter.fillRect(0, 0, this->width() - 1, this->height() - 1, brush);

QBrush brush(this->palette().background().color(),Qt::Dense4Pattern);
painter.fillRect(0, 0, this->width() - 1, this->height() - 1, brush);

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The problem is the that palette().background().color() doesn't return the right widget backgroung color. It returns an aproximate light color.

Am I missing something?