PySide QPainter.drawRect（）与QBrush偏移量问题

Question

I'm trying to draw my custom push button which has dimensions 20x20 pixels. I created a class that inherits QPushButton and I have overwritten paintEvent method with this code below:

painter = QtGui.QPainter(self)

x = self.rect().x()
y = self.rect().y()

width = self.rect().width()
height = self.rect().height()

painter.setBrush(QBrush(QColor(170, 97, 112)))
painter.drawRect(x, y, width, height)

And this is what I get (edited in Photoshop):

You can clearly see 1 pixel offset both in x, and y dimensions on the top left.

I was wondering why this is happening. I can get rid of this by extracting 1 pixel from x, and y and adding 1 pixel to width and height, so their value will be: x = -1; y = -1; width = 21; height = 21.

But this just feels wierd to me. I don't know if this is an issue with Qt (or maybe just PySide) or I don't understand something.

Answer 1

I think your getting confused about what QPainter::drawRect actually does. From the QPainter documentation

Draws the current rectangle with the current pen and brush.

The rectangle is filled with the current brush and outlined with the current pen. With that in mind I suspect that when you call QPainter::drawRect you have a pen active for the painter causing the grey outline you see.

If all you want is to fill the rectangle then you can use...

painter = QtGui.QPainter(self)
painter.fillRect(this->rect(), QBrush(QColor(170, 97, 112)))