how to change the left white space which QPainter doesnot draw in QWidget?

opengpu

how to change the left white space which QPainter doesnot draw in QWidget?
i did some drawing in paintEvent, however, the left area which didnot draw remains White, now i want to change this White into the color of its parent's background color which is normally light-gray in windows.

mrjj

Hi
Show the code :)
or an image at least.
Its not easy to understand what you mean.

opengpu

eg.
void paintEvent()
{
...
painter.drawRect(rect);//rect is smaller than the QWidget size
...
}
then the area not belong to rect remains white, and i want to change this white color.

J.Hilk

@opengpu is your widget managed by a QLayout of any kind? Because the "White space" may be just the margins defined in the layout.

opengpu

no, it's on Layout, but i am sure the white area is the area which i don't draw anything in paintEvent

dheerendra

Try something like this to fill the white space of your drawing.

void MyWidget::paintEvent(QPaintEvent*..) {
..
..
QRect r = this->rect();
painter.setBrush(//Set the parent color);
painter.drawRect(r).// draw the full background first
painter.setBrush(//Set the current color);
painter.drawRect(rect);//draw your rect

}

opengpu

is this inefficient?

opengpu

i tried, and it works, thank you!