How to get the height of QVBoxLayout ?

[NonNT]

How to get the height of QVBoxLayout ?

titles = QVBoxLayout()
titles.addLayout(QLabel('Title'))
titles.addWidget(QLabel('SubTitle'))

print(titles.contentsRect())  # =>  PySide2.QtCore.QRect(0, 0, 0, 0)

Pyside2 5.13.1 on Manjaro

[jsulm]

@NonNT Why do you need the height of a layout? Usually one is interested in size of a widget.

[JonB]

@NonNT
Apart from what @jsulm has just said.

I would assume the reason for QRect(0, 0, 0, 0) is that if the code is as you show the QVBoxLayout, and its widgets, are in limbo-land size-/layout-wise until you actually put them onto a window or actually show it? At minimum try putting the layout somewhere, and possibly have to wait till it's actually shown, not sure about that?

[J.Hilk]

@NonNT

I don't know how the python bindings handle this, but this:

titles.addLayout(QLabel('Title'))

should actually not be possible

besides that, @JonB is right, until shown, the content hight/width should be 0

[JonB]

@J-Hilk
Good spot, I didn't actually notice that! You can add a QLayout to a QLayout, but you can't pass a QWidget to addlayout()!

I don't know how the python bindings handle this

I tried in PyQt5, and get run-time error:

TypeError: addLayout(self, QLayout, stretch: int = 0): argument 1 has unexpected type 'QLabel'

PySide2 run-time error:

TypeError: 'PySide2.QtWidgets.QBoxLayout.addLayout' called with wrong argument types:
PySide2.QtWidgets.QBoxLayout.addLayout(QLabel)
Supported signatures:
PySide2.QtWidgets.QBoxLayout.addLayout(PySide2.QtWidgets.QLayout, int = 0)

Don't you just love it when Python has to run-time error where a decent language would pick it up at compile time :(

[J.Hilk]

@JonB lovely
do also not get a hint where in your files this happened?

[JonB]

@J-Hilk
Yes, they both gave me a stacktrace/code lines. Didn't paste, but I didn't mean to imply they did not produce those. Just that you only discover when/if you hit the code at run-time, where code above would not compile in C++. Since I have to use Python for my Qt work, I like to moan about it a lot ;)

[NonNT]

@J-Hilk Sorry, yes, it should be addWidget

logo = QSvgWidget()
logo.load('logo.svg')

titles = QVBoxLayout()
titles.addWidget(QLabel('Title'))
titles.addWidget(QLabel('SubTitle'))

titleBox = QHBoxLayout()
titleBox.addWidget(logo)
titleBox.addLayout(titles)

logo should have the same width as height, depending on the height of titles
but now the width of logo is dynamic, but should be fixed.
for logo.setFixedSize() I need the height of titles

thanks

[J.Hilk]

@NonNT
for such cases, QWidgets have a int QWidget::heightForWidth(int w) const but you have to override that function for it to work as indented. I'm not sure how to do this with python ..

---

Here's an example on how to do such a thing in c++, still working in Qt5.12 +
https://stackoverflow.com/a/18923122

[JonB]

@NonNT said in How to get the height of QVBoxLayout ?:

for logo.setFixedSize() I need the height of titles

As @J-Hilk has said, QWidget::heightForWidth() looks like the best way to go. (I don't know if https://doc.qt.io/qt-5/qsizepolicy.html#setHeightForWidth does it for you without override.) But if you are still asking to get the size of the layout, I don't see you have acted on what we said earlier?

[NonNT]

Don't know how to override QWidget::heightForWidth(int w)

But I can sum up the heights of the widgets and the spacing between the widgets.

title = QLabel(f'<h3>{self.title}</h3>')
subTitle = QLabel(self.subTitle)

widgetTmp = QWidget()
vboxlayoutTmp = QVBoxLayout(widgetTmp)
vboxlayoutHeight = title.sizeHint().height() + vboxlayoutTmp.layout().spacing() + subTitle.sizeHint().height()

logo = QSvgWidget()
logo.load('logo.svg')
logo.setFixedSize(vboxlayoutHeight, vboxlayoutHeight)

labels = QVBoxLayout()
labels.addWidget(title)
labels.addWidget(subTitle)

titleBox = QHBoxLayout()
titleBox.addWidget(logo)
titleBox.addLayout(labels)