[Qt-interest] Height of QPushButton and QLineEdit different

[Girish Ramakrishnan]

Hi Oliver,

Oliver Demetz wrote:
> Hi,
> thank you for your extensive answers and the deeper insights on this topic.
> For one widget, where I use a QHBoxLayout for positioning and sizing of
> the controls, the proposed
> 
>     lineEdit.setFixedHeight(button.sizeHint().height())
> 
> worked fine. It is also to some extend "elegant" and still readable in a
> year ;-)
> 
> But in another widget, I am doing the whole layout by hand in the
> resizeEvent function by calling setGeometry on each control.
> 
> There, I get again a problem, because calling
> 
>     lineEdit.setGeometry(x,y, 150, 30)
> 
> does not lead to a height of 30! It is again smaller.
> And until the last reply I thought that calling setFixedHeight is as
> good as working with setGeometry.
> 

I cannot tell for sure why it is smaller - there can be various reasons,
maybe a fixed size is set or a minimum/maximum size is set. Maybe
showing us some simple code that doesn't work can help.

> In practice, all those QLayout-subclasses do nothing else but calling
> setGeometry on their widgets, don't they?
> 

Partly true. They do also set the minimum and maximum sizes based on
size constraints.

Girish

> Regards,
> Oliver
> 
> 
> Jens Bache-Wiig schrieb:
>> Good answer Girish!
>>
>> Actually I was thinking about adding some layout assistance on this
>> topic not too long ago. It seems like a common use case that you would
>> want to align controls at the same height. Perhaps a
>> setHomogenous/setUniformHeight property on boxlayouts would be the way
>> to go in the future so people can hint that their layouts should stay
>> uniform.
>>
>> Jens
>>
>>
>> "Girish Ramakrishnan" <girish at forwardbias.in> wrote in message
>> news:4A2E4C4A.5010804 at forwardbias.in...
>>> Hi Oliver,
>>>
>>> Oliver Demetz wrote:
>>>> Hi all,
>>>>
>>>> Simple example:
>>>>
>>>>   QHBoxLayout * lay = new QHBoxLayout;
>>>>   lay->addWidget(new QPushButton("Hello World"));
>>>>   lay->addWidget(new QLineEdit("Foo Bar"));
>>>>   this->setLayout(lay);
>>>>
>>>> Executing this code, you will see, that the QLineEdit's
>>>> height is smaller than the QPushButton's height.
>>>>
>>>> I think it depends on the particular system, but on
>>>> my Windows box here the button has height 28 whereas
>>>> the lineedit only has 22 pixels.
>>>>
>>>> *How can I adjust this???*
>>>>
>>>> I tried several things:
>>>>
>>>> (A:)  lineedit->setMinimumSize(button->height());
>>>>     Didn't change anything.
>>>>
>>> The height() is usually not a valid size until the layout has got a
>>> chance to provide geometry to child widgets. Also, height() is the
>>> actual height() that you see on the screen. You will have to manually
>>> activate the layout to make height() something reasonable before the
>>> widget is visible. But even then, after the widget is shown, it may get
>>> a different height().
>>>
>>>> (B:)  lineedit->setMinimumHeight(button->height());
>>>>       lineedit->setMaximumHeight(button->height());
>>>>      Leads to crap, the lineedit gets a huge height,
>>>>      I don't know why.
>>>>
>>> Same as above, height() won't be valid.
>>>
>>>> (C:)  lineedit.setSizePolicy(
>>>>                 lineedit.sizePolicy().horizontalPolicy(),
>>>>                 QSizePolicy::Ignored);
>>>>       The idea is to make the lineedit *expand* in the
>>>>       layout in vertical direction, but this leads also
>>>>       to a way too huge height
>>>>
>>> The layout sets geometry based on widget's sizePolicy + sizeHint. The
>>> push button has a fixed size policy in its vertical direction. This
>>> means that if the sizeHint returned 80px vertically and the layout has
>>> 100 px of vertical space, the layout would resize the button only to
>>> 80px (and use alignment to figure out the position). When you set the
>>> line edit's policy to ignored, the layout would make the line edit 100px
>>> in height. See the problem?
>>>
>>> One solution is to just
>>> lineEdit->setFixedHeight(pushButton->sizeHint().height()); sizeHint will
>>> take care of polishing, so you don't need ensurePolished().
>>>
>>>> Why are the recommended heights for these two controls
>>>> different at all?
>>>>
>>> Girish 
>>
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