[PyQt] QVBoxLayout default (minimum) size

[deanhystad]

According to the Qt documentation, layouts contentsMargins are usually 11, not 9.

https://doc.qt.io/qt-6/qlayout.html#setContentsMargins

By default, QLayout uses the values provided by the style. On most platforms, the margin is 11 pixels in all directions.

This is inherited from the base class QLayout, so I would expect it to be the same for all layout managers unless changed by a style.

I wrote a little test and this appears to be true for PySide6.

from PySide6.QtWidgets import QApplication, QWidget, QVBoxLayout, QGridLayout, QPushButton

class Box(QWidget):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        layout = QVBoxLayout(self)
        print(layout.contentsMargins(), layout.minimumSize())


class Grid(QWidget):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        layout = QGridLayout(self)
        print(layout.contentsMargins(), layout.minimumSize())

app = QApplication()
box = Box()
grid = Grid()
box.show()
grid.show()
app.exec()

Output:
<PySide6.QtCore.QMargins(11, 11, 11, 11) at 0x000001F1DEB4E380> PySide6.QtCore.QSize(22, 22)
<PySide6.QtCore.QMargins(11, 11, 11, 11) at 0x000001F1DEB4E440> PySide6.QtCore.QSize(22, 22)