I said 'Maybe you've a typo...'
The problem with auto-connect is that you can not be sure if it is really connected (e.g. when there is a typo somewhere in the functions signature or the ui element name) and it easily breaks (e.g. when renaming an ui element).

Hi and welcome to devnet,

First thing, please don't delete all that stuff in your destructors. Qt has a pattern that is based on parent widget (the parameter "this" in widget constructors) that take care of destructing all the children automatically when the parent is deleted: http://doc.qt.io/qt-5/objecttrees.html

Now regarding your problem, only one widget can have focus at the same time. For the focus part, you can use setFocusPolicy on your widgets, giving an enum that tells more about the behavior you expect.

For what I have experienced, playing with opacity and trying to give a modern look to a desktop software is kind of a pain. Long story short: there is no user friendly API to do so, or at least as user friendly as what QML provides. This is either because the widgets part is late compared to the QML one, or because "modern" has been associated with app, browsers, Internet, but not with desktop. Nonetheless, things might evolve in the future, since Qt developers have communicated about resuming the widgets development. This doesn't solve your problem, but could explain why you are having so much trouble trying to code an overlay that behaves with good focus policy, and using low level code such as QPalette that is always a sign you're doing something wrong, or at least not initially intended. Which could be fine, if you really know what you're doing, and you are aware that you'll have to deal with a lot of work to make your application look the same on every platform.

EDIT:
So I created a project with your code and here are some remarks:
1 Do not set a layout to your main window, just set the central widget with, well

setCentralWidget(widget)

2 qreal is an alias for double, so instead of qreal(100)/100 just write 1.0; same for qreal(50)/100, just write 0.5 and it will be perfectly fine.

3 No need to use "this->" you are coding in C++, not JAVA ;)

For your problem, I think I don't really get what you are expecting. Just an overlay when the setting widget pops? If so, maybe working with a QDialog (a modal one) would be better.

Hi
The qemf seems able to only rendering of EMF not generating it.

What is the data you want to put in the emf file ?

Qt has http://doc.qt.io/qt-5/qpicture.html#details
that works like WMF but its not same (file) format at all.

However, its pretty simle to generate WMF/EMF from windows API.
(CreateEnhMetaFile)

@raven-worx said in QWheelEvent & Siblings/Children:

@J.Hilk said in QWheelEvent & Siblings/Children:

Currently I do this with a signal that has the QWheelEvent* as argument

why not directly forward the event to the child widget instead?
(using QCoreApplication::sendEvent())

Well, yes, that seems exactly like the proper way to do it!
I'll look further into it, thanks!

Yes this is exactly what I was looking for. Solved!

@jsulm Ok! I will make sure to read all the links you've given me. Thanks for the help!

@im_vidhya - Look at the QScreen class. There are functions to give you the available screen size, for example.

But if you do the layout correctly, as Christian pointed out, then the user can resize the windows just about any way they want without problems. Qt layouts take care of the rest. I only use the information from QScreen to show my main windows in a reasonable initial default size, centered on the screen.

@sierdzio said in QWidget: Cannot create a QWidget without QApplication - OpenCV imshow() 2.4.13 ?:

Is Qt the only supported backend? If yes, then indeed requirements do propagate.

No, it has been added later on. It's maybe even the latest that has been implemented.

AFAIK, what the OP is hitting here, is that OpenCV doesn't have an implementation for imgshow for iOS. It would require to either use Qt to show the result of what he's doing or native stuff.

Why not implement my original suggestion ? Put a QLabel and your grid widget in a QStackedLayout and change to the label and back as needed ?

Hi
Does the custom CustomQWidget do its own drawing with QPainter ?

@artudi54 Tested with gnome on arch and it does the same thing. I'd say this is a bug since d.show() never pulls the window back up.

I would file the bug with Qt.

To work around it I just made sure to call d.hide() before hiding the main window. Then after w.show() just call d.show() again.

@magicstar
Thanks i landed up using this.
Worked

Also, if you are on Qt 5.4 or newer, I suggest replacing QGLWidget with QOpenGLWidget. QOpenGLWidget resolves numerous issues with QGLWidget: https://blog.qt.io/blog/2014/09/10/qt-weekly-19-qopenglwidget/

Hi,

What do you mean by regular string ?

If it comes from the Windows API, you should then consider using QDir:: fromNativeSeparators.

Hi and welcome to devnet,

You should take a look at the various IPC options provided by Qt.

Hi,

IIRC, since 5.8 or 5.9, QtMultimedia has OpenGL (vertex/fragment shaders) support for that kind of format. You should take a look there.

It uses the raster engine. See here for historical informations.

Hi,

See my answer one the other thread.

@SilverSurfer I don't have the time handy to do a full working example, but this is the technique in glsl:
https://www.khronos.org/opengl/wiki/Data_Type_(GLSL)#Swizzling

(The vec4 can hold "rgba" values if that's what you put in it - the example there just calls it "xyzw" because the data type generically handles any 4 floats.)

Basically, start from an example that draws an image with a simple glsl shader as a texture. Then hack on the shader until it flips around the colors like you want when it draws the texture. Then use your code that gets the image over the network to upload the image as the OpenGL texture every frame.

Hi
You did read ?
http://doc.qt.io/qt-5/stylesheet-examples.html#customizing-qscrollbar

@SolaVitae
Ok then the default
classes will just work.

Maybe you can try with
http://doc.qt.io/qt-5/qtwidgets-widgets-imageviewer-example.html

1st of all, thanks for your effort, I use LyX myself.

The doc says:

this indicates that the widget will paint over its entire area with opaque colors. The widget's area will initially be uninitialized

set the widget's Qt::WA_OpaquePaintEvent, avoiding any unnecessary overhead associated with repainting the widget's background

Meaning it is saying it won't bother painting a background but it's not committing to leaving the old painted background in place so I still think you are relying on undefined behaviour.

On the other hand, I think this also impacts the performance of widgets with Qt::WA_OpaquePaintEvent on macOS so it is probably worth highlighting it with a bug report and/or an email on the mailing list

Hi and welcome to devnet,

Do you have any static QWidget based class in your library/application ?

Yeah i feel like i do sudo apt-get update && upgrade at least once a day. I just checked about SIP and i compiled it from source but i cant remember if i actually used the command make and make install. Does that mean i have to reinstall pyqt5 again? I guess i just open a new thread. Thanks for all the help @SGaist

It might not be the answer but it is a answer. I declare my charts using QML to maintain declarative / visual design.

I only control them from C++ with C++ data. I do all the processing of dynamic axis ranges inside that, I do stupidly high frequency updates.

I'd recommend, if you very frequently update your line series like I do to use: void QXYSeries::replace(QVector<QPointF> points) (or QList...)

and also set your LineSeries to use open GL either from QML or C++ works fine, you do lose some functionality but it saves using canvas (which is slower) if you have lots of points of data, with many fast updates.

HTH

I have found a solution that kind of does the job, although takes three times as much memory.
Every update I calculate the difference between the new and the old saturation matrix, this eliminates 60% of the nonzero values, which means it gets drawn that much faster.

As a second layer of optimization I call repaint with a rectangle describing the most important zone, and call update every 60ms.

@raven-worx

Great, it works.

Actually I did try setting QTabWidget setAutoFillBackground(True) previously, but it didn't work.
Now I tried set VGroupBox setAutoFillBackground(True), then the color changed to light grey which is the exact default color I need.

Thanks so much, raven-worx.

@SGaist

I have tried to get an example to the problem I saw apparently, but I did not succeed. For a simple radio button it is working, but the layout's margins need to be set to 0 either with setMargin or setContentsMargins.

For the small example I have generated I had introduced also the derived class I used and it seems to work there. Therefore, there must be another problem with the QTableWidget's implementation or I simply fall into a trap.

Therefore, I will mark as solved.

Well seems that it needs to emit model's layoutChanged() to do what I need. I created new class which inherits QListWidget and there I connected signal to layoutChanged signal of model() object and it worked.

Just realized, that I had still thread still open.

I'll share how I managed to circumvent the problem. Sadly I haven't found a real solution as of now.

In the function that makes the screenshot, I added this line just before calling QWidget::render

this->setStyleSheet("cStackedWidget {background-color:white;}" "QWidget#LiveStatus{background-color:white;}" ... //List of all QStackedwidget Pages ... "QWidget#FanThreshhold{background-color:white;}");

For some reason I have to set the stylesheet new for each time. Simply setting this once will not work.

Anyway, I'll mark it as solved,
unless someone else has a new idea !?

No, it doesn't. The QLayoutItem is not the parent of the widget, it is not a QObject. That's not its job.

Yes, a file with size 0 kb is being created

There is not reported this specific bug but other very similar which roots in window frame handling by Qt.
For example:
https://bugreports.qt.io/browse/QTBUG-53368?jql=text ~ "frame size windows"
https://bugreports.qt.io/browse/QTBUG-31735?jql=text ~ "frame size windows"
https://bugreports.qt.io/browse/QTBUG-14613?jql=text ~ "frame size windows"

You can add a widget to the scene using QGraphicsProxyWidget *QGraphicsScene::addWidget(QWidget *widget, Qt::WindowFlags wFlags = Qt::WindowFlags()).