How to apply QStyleSheet Formatting on WhatsThis text

[A Former User]

Hello,

I have a file with Qt stylesheet information to change the look of my application. Within that file, I set the way a QToolTip is displayed like this:

QToolTip 
{
  border: 1px solid rgb(64,255,0);
  background: rgb(255,255, 127);
  border-radius 3px;
  padding: 2px;
  color: rgb(67, 67, 67);
}

Everything works fine and the tool tips look exactly like I would expect them to look. However, the tips that are displayed in WhatsThisMode are not formatted with this style. QWhatsThis isn't listed among the QWidgets that can be formatted in the Qt documentation but I'm pretty sure there must be a way.

Has anybody seen this before and has a solution to it?

Thanks!

[mrjj]

@tobiSF said in How to apply QStyleSheet Formatting on WhatsThis text:

WhatsThisMode

Hi
Its just a widget
class QWhatsThat : public QWidget
but not same window as tooltip

did you try
QToolTip, QWhatsThat
{ ..

[A Former User]

Hi @mrjj,

I don't think QWhatsThis is a QWidget, at least not with Qt5. I looked up the class declaration and it looks like this:

#ifndef QWHATSTHIS_H
#define QWHATSTHIS_H
#include <QtWidgets/qtwidgetsglobal.h>
#include <QtCore/qobject.h>
#include <QtGui/qcursor.h>
QT_REQUIRE_CONFIG(whatsthis);
QT_BEGIN_NAMESPACE
class QAction;
class Q_WIDGETS_EXPORT QWhatsThis
{
    QWhatsThis() Q_DECL_EQ_DELETE;
public:
    static void enterWhatsThisMode();
    static bool inWhatsThisMode();
    static void leaveWhatsThisMode();
    static void showText(const QPoint &pos, const QString &text, QWidget *w = Q_NULLPTR);
    static void hideText();
    static QAction *createAction(QObject *parent = Q_NULLPTR);
};
QT_END_NAMESPACE
#endif // QWHATSTHIS_H

However, I also did try to assign a style using the combined QToolTip, QWhatsThis{ ... } way and doing separate style definitions, none worked.

Thanks,
Tobias

[mrjj]

Oh
In 5.9
its "C:\Qt\5.9.1\Src\qtbase\src\widgets\kernel\qwhatsthis.cpp"
its
class QWhatsThat : public QWidget

Note the "that"

so seems to have changed. Or i have wrong file ?
It seems to match the docs though.

What version is your code from`?

[A Former User]

I'm using 5.6 here and I just checked the .cpp file. You're right, it inherits QWidget. Which makes it even less understandable why a simple stylesheet like this wouldn't work:

QWhatsThis
{
  background: rgb(255,255,127);
  color(67, 67, 67);
  ...
}

I am using the public static method enterWhatsThisMode() to put my QDialog into WhatsThis mode and show the respective help texts for each widget in the dialog.

[mrjj]

@tobiSF
do you apply the stylesheet to Application ?

I wonder what QWhatsX is a child of. (runtime).

Also my class is called/ends with That
Yours are really called QWhatsThis ?

[A Former User]

@mrjj,
yes, I have a static method ApplicationStyleManager::loadDefaultStyle() that loads and sets the stylesheet:

void ApplicationStyleManager::loadDefaultStyle()
{
	QSettings settings;
	QString path = settings.value("style/default.qss").toString();

	if(!path.isEmpty())
	{
		QFile file(path);
		if (file.open(QFile::ReadOnly))
		{
			QString styleSheet = QLatin1String(file.readAll());
			qApp->setStyleSheet(styleSheet);
		}
	}
}

I have also taken a closer look at the code. I have a qwhatsthis.h and qwhatsthis.cpp file in my Qt source directory. The header file containts a QWhatsThis class declaration. But the source file contains some other declarations and implementations, among others a QWhatsThat class that inherits QWidget.

I've tried applying a style in my stylesheet file to QWhatsThat instead of QWhatsThis but with no change.

[mrjj]

For test, can you try with QWidget as specifier and see if
QWhatsThis is affected at all.

One should think its at least child of the app and should be affected

Best part is that doc says
"If you specify a rich text formatted string, it will be rendered using the default stylesheet"

So clearly stylesheets should work/it knows about it.

Update:
If using no tags, so ALL widgets are colored in whole app, the WhatisThat is not affected.
So either is not a widget or the window is not attached to the app and hence not using its style or
it uses a stylesheet internally and override any globals.

[A Former User]

I actually tried to format the QString I'm setting into the widget like this:

QString help = QString(tr("<span stlye=\"padding: 3px; border-radius: 5px; border: 1px solid rgb(64,255,0), background: rgb(255,255,127); color: rgb(67, 67, 67)\">Test</span>"));
setWhatsThis(help)

However, it did not have any effect.

I do have a style for QWidget and that's also not affecting the QWhatsThis.

[mrjj]

I also tried it.
Nothing affects it. :)

I looked in
QWhatsThat::paintEvent(QPaintEvent*)

Its not using any Styles to draw it and hence cannot be affected as it is not really using the QStyle.
At least that is how i read it.

It does use palette.
p.setPen(QPen(palette().toolTipText(), 0));
p.setBrush(palette().toolTipBase());

[mrjj]

Ok
so palette will affect it
QApplication a(argc, argv);
QPalette p = a.palette();
p.setColor(QPalette::ColorRole::ToolTipBase, Qt::red);
a.setPalette(p);

does color background red.

[A Former User]

Ah okay. Not really what I am after, the idea is to load different stylesheets and apply them at runtime of the software. But if that's the only way to get the tip look decent, I guess it's what I'll do.

Thanks a lot @mrjj

[mrjj]

Well its a bit odd it is not made like Tooltip and respect stylesheets.
You can change text color and background color with palette and the drop shadow also seems to use palette entries.

you can use palette in stylesheets like
"background-color : palette(light)"

but not seen a syntax to set the palette from inside so not sure there is any good path for
use stylesheets with WhatIsThat, unless you steal/reuse the css parser and
use it to extract color values and then set the palette for the WhatIS widget.
(if you need it truly dynamic)

Np. it was interesting case :)

Also , i might be wrong :) but in other widgets there is lots of
QStyle->draw etc
and WhatIsThat seems to use nothing of that so I assume its the real reason why nothing happens with stylesheets.

[A Former User]

I agree, it seems like an oversight and I'm going to write an email to support and ask them about it. In the meantime I just use palette. It's not a huge deal with respect to the whole project but I hate when a logical structure behind an architecture has to be altered because of stuff like this.

[mrjj]

@tobiSF
Sounds like a good plan. Would be great to know the exact details.
I do understand its far from optimal to have one window that do not
use same styling system as all the rest.

It seems not possible to subclass and replace the widget without resort to event filters and
some amount of copy pasting code from the original widget.
I mean something like qApp()->setWhatisWidget(xx)