QT program's display gets frozen and scrambled - qt

I haven't found anyone who's stated a problem similar to this, but then again maybe it's because I don't know the right term for the graphical glitch I'm having. This program worked and displayed just fine a week ago, but now it doesn't. I (or rather, "we," since it's a school project) haven't made any changes to it since then. It's made with QT, and running on CentOS. Here's a screenshot:
Screenshot of QT glitch
Whatever is behind the window shows in the background, and whatever happens in the window gets frozen on screen. For example, if a word is supposed to flash on the screen and then disappear and be replaced by another word, the first word does not disappear. Instead, the second word just appears on top of it.
Anyone able to point me in the right direction as to what could be doing this? I could post a code snippet, if I knew what part to post a snippet of. :S

Is the UI just one giant QGraphicsScene object? If so then it could well be an OpenGL driver issue. If not, then I'm going to guess that it's the underlying Qt painting system that has become corrupted, and just reinstalling Qt should do it.

Related

I have a problem with qt-designer app. The preview differs of what I get as a result. It worked properly before - now doesn't

The thing is that in preview workspace I have all the elements aligned left no matter what I chose in the alignment, but when i press Ctrl+R it shows me that elements are aligned properly. Of course it's good that it works in further usage, but I'd like to see what I'm doing and how it looks right in workspace.
If someone had the same problem and knows how it can be solved, please write your answer. Thank you in advance)
The photo is linked here:

Incorrect Ikonli icons displayed

I am having problems using the Ikonli icon packs. I am creating FontIcon objects and then using those to set the graphics on buttons. Icons taken from the FontAwesome5 pack work great. Icons taken from the Material2 pack seem to shift somehow - for example, I try to get mdal-6_ft_apart but what actually gets displayed is mdal-loyalty. And no matter which Icon I load from MaterialDesign2, all I see is an empty box.
I'm running this through Eclipse, and everything looks fine when stepping through with the debugger. This is the value of the button graphic:
ObjectProperty [bean: mdal-6_ft_apart:15:0xffffffff, name: iconCode, value: MDAL_6_FT_APART]
and yet, on the screen, it's something completely different.
This is a Maven project using OpenJDK 16 and JavaFX 16. I've tried loading just a single icon pack instead of all 3, but no difference. Also, there are never any errors retrieving the icons. The ServiceProviders are all found, and the icons are available.
I made a small Hello World program and everything runs fine, so it's definitely an issue with my program and not the library. But I have no idea what the problem is, and I've been staring at this for almost 2 hours. Has anyone come across this before? I'd appreciate any help, because I'm out of ideas.
Answering this myself in case it saves someone else some time. I was installing the Ikonli library in order to replace the FontAwesomeFX library that is no longer available. I had gotten partway through replacing the icons when I ran the app in order to check the progress, and that's when I saw the errors.
The problem turned out to be an interference between the two libraries - FontAwesomeFX was throwing of Ikonli. The icon shift didn't actually occur until the code displayed a FontAwesomeFX icon, which made it seem a little random depending on the order I would open the dialogs when testing. I'm assuming an issue with the Service Handlers, though I'm not positive because I stopped troubleshooting once I realized the problem and just finished the replacement.
Once I stopped displaying FontAwesomeFX icons and the dependency was removed, Ikonli worked fine.

JavaFX - Nodes Whiting Out

Hi I have quite an unusual query. I have made a small JavaFX program and am very proud of the results. However I recently noticed a bug I can't seem to rap my head around. I can't recreate it either and do not have a screen shot of it unfortunately. However you can see a screenshot of the general program below in the state that triggered the problems.
I was running my program like normal and gave it quite a large load to handle (a lot of gradients as seen below). Then what happened was that in any TextField I typed in all edited text became a completely white rectangle and if I tried to update the image preview to the right it also turned white. If I let the program be in this white state for about ten seconds everything would load back in and behave like normal until I went to edit anything again.
It happened with any StyleSheet I loaded and as mentioned I cannot seem to recreate it. So my question is this. Is this a known error that can occur if you configure your scene in the wrong way (or something similar) or have I just managed to screw things up in general? The source code is quite long and I have absolutely no Idea where the problem may lie so I won't post any if you don't feel like a specific part may be interesting.
I am also aware that this type of general question is not really liked here so sorry about that. If you can suggest another more suitable forum I would be more than happy to move my question there.
//Thanks for any help.
EDIT: I finally managed to get a screen shot of the bug. I am not having high hopes that anyone is going to answer this though...

Using QT For Creating a Screen Dimmer

I'm trying to implement a screen dimmer using QT4 and I wanted some advice before I get cracking instead of going into this blindly.
I want to create a top-level window that has no frame. I was thinking of making the background black and messing with the opacity so that it will dim the screen out after the system is idle for a given period of time.
The problem with this is that if this window is always on top, how can I pass click events to the window underneath it? I'm not the least bit familiar with the windows API (the solution only has to work under windows), but I'm guessing that's a good place to start. Can anyone point me to some useful classes/functions or suggest another way of doing this via QT?
If anyone's interested in the solution I came up with and the windows API functions I used, you can check out my blog posting here: http://sarcastichacker.com/getnextwindowandgetforegroundwindow
I will be updating the source and making another related posting on the same blog within the next couple of days.

Strange Error in Xcode 4 that persisted across different versions of the same file

I want to preface this question by admitting that I'm still very much a novice, to Xcode 4 and to development in general. But I find I learn the most when I've made mistakes and been able to discover ways to correct my errors.
So I was mucking about in Xcode, following an example in the book I've been studying, in this case trying to determine why the keyboard wouldn't hide when I touched outside a text field. In the process of experimentation, I tried adding an Outlet to the top level View of a View Controller, dragging into the Header file to automagically create it. I knew almost at once this wasn't what I wanted, and I deleted the reference in Interface Builder, and the code it had added to the other files.
And when I did run the program, it threw an exception. Being new to this, I didn't think to check the log files, and when I couldn't work out what the error was, I restored an earlier version of the project from Time Machine, and tried again -- same result. I restored an even earlier version and tried again -- and got the same error!
When I finally did have the good sense to look at the log file, I noticed the reference to the name of the Outlet I had added, but removed! But these were older versions of the code, before I'd even made that change.
I made a thorough search of the code, and my NIB file, looking for any reference to the deleted Outlet. I couldn't find anything.
I eventually replaced the NIB file with a version from the tutorial from the book I was following (it was identical, and easier than rebuilding it from the bottom up), and all was well, everything ran just fine. But now I'm left wondering -- what could I have done to make this error so persistent, across different versions of the file? I'm already kinda uncertain about the way Xcode 4 will automagically add code under certain circumstances (that's probably more dangerous than useful for the novice), and I wonder if this is a bug in Xcode 4, or if I inadvertently tripped over a useful feature.
Xcode loves to play tricks on you. I've several times gotten an XIB mysteriously hosed up to the point where I had to delete it and start over. No matter what I'd do to the XIB some elements wouldn't display correctly (or at all).
In a recent case I had an XIB with a label with the text "Start date:". I changed that label text to "Treatment date:", but it still kept coming out "Start date:". I opened the XIB as text and scanned for "Start date:" and it wasn't there. So I tried dragging the label off to one side. Then it displayed the correct words. Dragged the label back to the correct place -- back to "Start date:". I finally deleted the label and recreated it and then the text came out correctly.

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