I have a plugin for Homebridge that operates shades, i.e. WindowCovering Services. It basically imitates the remote for the shades. The remote has 16 channels and one of them, 0, operates all shades. Each shade/channel is an Accessory on a Dynamic Platform. As the shades move I am updating the CurrentPosition and PositionState Characteristics. This seems to work fine now. However, some updates never seem to reach Homekit.
When multiple shade/channels are moving at the same time, this shows in the Home app as "Opening" or "Closing". When the PositionState is updated to Stopped, the icons show the current %age open. However the updates on some shades will get lost.
I thought perhaps a delay between update calls is required, so I implemented a scheme that prevents calls being made close together with a configurable delay. That seemed to improve things, but updates are still lost and I don't really know if the delay is required.
All PositionState updates go through this code. I have been debugging this issue for quite a while and am convinced the code is executed, but I can't figure out why the Home app does not see the Stop.
updateStateCB() {
this.service.getCharacteristic(this.platform.Characteristic.PositionState).updateValue(this.positionState);
this.logTimeCh('Update state:' + this.positionState);
}
Where might I be going wrong here? Is the delay between calls required? Is there a bug in Homekit somewhere?
Thanks
I use Qt's wheelEvent to implement scrolling in a custom widget. Normally, this works fine.
However, when dragging the mouse and scrolling with the mouse wheel at the same time, it sometimes happens that rotating the mouse wheel by one step does not do anything at first (no wheelEvent is received). This might even randomly happen a few times successively. The next time the application does receive a wheelEvent, it comes with an accumulated event->angleDelta() of all previous events that were not reported separately. Apparently the events are buffered together in this case. Note that the wheelEvent may happen a long time after the initial mouse wheel rotation(s) in this case: it only happens once the wheel is rotated again.
This is an issue, since it means that my widget sometimes does not properly react to scrolling. Is there any way to avoid this kind of buffering and receive all wheel events immediately instead?
Notably this behavior is only well reproducible if at the same time dragging the mouse within the widget, which performs some non-trivial actions as a result. So I suspect it might happen if the event loop seems busy. But it certainly isn't busy enough to be unable to handle each wheelEvent. So I would like to disable this buffering.
I observe this on Linux with Qt 5.12.0. Any help is appreciated, thanks.
I am answering my own question here since I found the answer after writing it (but was unable to google it before).
The same problem has been reported here (with a somewhat non-descriptive title): Qt QOpenGLWidget wheelEvent strange behaviour
For me, setting Qt::AA_CompressHighFrequencyEvents (see https://doc.qt.io/qt-5/qt.html#ApplicationAttribute-enum) to false seems to have fixed the issue, as posted by #gatis paeglis as an answer to that question.
Currently, I am able to hook onto Direct3D application and draw custom stuff onto its surface. However, I would like to suspend this application and then draw something else.
Is this even remotely possible to do so? Like creating another my own Direct3D window on top of that application?
I'm targetting only Windows 7, but the application I want to draw on is using only DirectX 9.
The problem is that I have very little experience with DirectX in general.
Sort of.
You're working with two different elements here, one quite large and but not particularly complex: hooking D3D. The other ("suspending" the app) is simple within that, but you don't quite want what you think you want.
To hook D3D, by the simplest method, you need to intercept the call to CreateDirect3D9 and return your own IDirect3D9, which later creates and returns your own IDirect3DDevice9. This will give you full control over the app's render process.
In order to "suspend" it, you need to wait for the desired trigger, then in your IDirect3DDevice9::Present, call your own event loop. This will, for all intents and purposes, suspend execution of the original app's code, but not the process itself (allowing your code and event loop to process). There will be some limitations of this, and you may not be able to consume window/Windows events (simply), but it will give you full control and effectively pause the original app.
Note, however, that you must intercept and reroute execution in every thread you want to "suspend," it's only specific to a single thread and you don't want physics or AI crunching on while render and UI are paused.
You need to perform your overlay drawing, whatever that may be, during your loop or your IDirect3DDevice9::Present hook, then call the real device's Present method as needed. If you want to run multiple frames of your overlay, then call the real Present repeatedly before returning from your Present. Tweak as necessary. Rendering here is done pretty much normally (check out general D3D tutorials for that), but there is one major catch: the device's state is unknown and may be incompatible, but must be "untouched" on return. This is handled simply by caching an IDirect3DStateBlock9 created from the device immediately after creating it. In your Present hook, create another state block with the state on entrance, restore the clean state block, run your code, then restore the entrance state block. You can work with any states, off a fresh slate, without damaging the device's state (I use this in practice, in works great).
If you want some rather extensive examples of how this works, I'd suggest checking out the Voodoo Shader project, which has full D3D8 and 9 hooks, including everything needed for overlays [/shameless own-project promotion]. Feel free to reuse any of the concepts, or comment with further questions; this certainly isn't all the details that may be useful to you.
This is a very complex thing to accomplish, as it is very much a hack to do so. The only people you see doing such things are steam, teamspeak, xfire, fraps, and a few hard-core devs.
There are kits out on the internet that show you have to inject a DLL into the memory space of the target application to achieve such a feat, and methods such as proxy DLLs.
Proxy DLL:
http://www.codeguru.com/cpp/g-m/directx/directx8/article.php/c11453
Injection:
http://www.progamercity.net/d3d/372-c-directx9-0-hooking-via-detours.html
Good luck, this will take you a while.
Can someone recommend a straight forward way of adding some type of graphical notification (status bar, spinning clocks, etc...) to my wx.Python gui application? Currently, it searches logs on a server for unique strings, and often times takes upwards to 3-4 minutes to complete. However, it would be convenient to have some type of display letting a user know that the status of the job towards finishing/completion. If I added a feature like this, I'm not sure, but I'm afraid I may have to look at using threads ... and I'm a complete newbie to Python? Any help and direction will be appreciated.
Yes, you'd need to use threads or queues or something similar. Fortunately, there are some excellent examples here: http://wiki.wxpython.org/LongRunningTasks and this tutorial I wrote is pretty straight-forward too: http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/
Using threads isn't that hard. Basically you put the long running part in the thread and every so often, you send a status update to your GUI using a thread-safe method, like wx.PostEvent or wx.CallAfter. Then you can update your statusbar or a progress bar or whatever you're using.
Can anyone give me a scenario where they think busy cursors are justified? I feel like they're always a bad idea from a user's perspective. Clarification: by busy cursors, I mean when the user can no longer interact with the application, they can only move their hourglass mouse pointer around and whistle a tune.
In summary, I think that the user should be blocked from doing stuff in your app only when the wait interval is very short (2 seconds or less) and the cognitive overhead of doing multi-threading is likely to result in a less stable app. For more detail, see below.
For an operation lasting less than 0.1 second, you don't usually need to go asynchronous or even show an hourglass.
For an operation lasting between 0.1 and 2 seconds, you usually don't need to go asynchronous. Just switch the cursor to the hourglass, then do the work inline. The visual cue is enough to keep the end-user happy.
If the end-user initiates an operation that is going to take just a couple of seconds, he's in a "focused" mode of thinking in which he's subconsciously waiting for the results of his action, and he hasn’t switched his conscious brain out of that particular focus. So blocking the UI - with a visual indicator that this has happened - is perfectly acceptable for such a short period of time.
For an operation lasting more than 2 seconds, you should usually go asynchronous. But even then, you should provide some sort of progress indicator. People find it difficult to concentrate in the absence of stimulation, and 2 seconds is long enough that the end-user is naturally going to move from conscious ‘focused’ activity to conscious ‘waiting’ activity.
The progress indicator gives them something to occupy them while they are in that waiting mode, and also gives the means of determining when they are going to switch back into their ‘focused’ context. The visual cues give the brain something around which to structure those context switches, without demanding too much conscious thought.
Where it gets messy is where you have an operation that usually completes in X time, but occasionally takes Y, where Y is much greater than X. This can happen for remote actions such as reaching across a network. That's when you might need a combination of the above actions. For example, consider displaying an egg-timer for the first 2 seconds and only then bringing in your progress indicator. This avoids wrenching the end-user from the 'focused' context directly to the 'waiting' context without an intermediate step.
It's not specifically the busy cursor that is important, but it IS important, absolutely, always to give feedback to the user that something is happening in response to their input. It is important to realize that without a busy cursor, progress bar, throbber, flashing button, swirling baton, dancing clown.. it doesn't matter ANYTHING- if you don't have it, and the computer just sits there doing nothing, the computer looks broken to the user.
immediate feedback for every user action is incredibly important.
I think you may well be right: in a decent asynchronous app, you never need to show a busy cursor. The user can always do something even if the big last operation is completing.
That said, sometimes Java apps like Netbeans or Eclipse, or even Visual Studio, hang with no busy cursor and no hope. But in that case, a busy cursor probably wouldn't help much either...but I think you're right: busy cursors are from a non-multithreading era for apps. In Flex apps, for instance, EVERYTHING is automatically event-driven callbacks, so setting a busy cursor would just be meaningless (though possible, of course).
You show a busy cursor when the user can not do anything until the operation is completed - including exiting the application.
I find it interesting that you don't see busy cursors in Web Browsers - perhaps that why people like them so much.
No, wait, I have a better answer. You show a busy cursor when the computer is thinking.
When one hits the Refresh button on a web browser, busy cursor must appear immediately to tell the user to let them know that a page is being loaded.
I think it was Don't Make Me Think that said that the tolerable loading time for human is zero second.
Google says:
Responsive
It's possible to write code that wins
every performance test in the world,
but that still sends users in a fiery
rage when they try to use it. These
are the applications that aren't
responsive enough — the ones that feel
sluggish, hang or freeze for
significant periods, or take too long
to process input.
There are two purposes for it:
Indicate for the user that something is happening.
Indicate for the user that nothing can't be done right now.
Busy cursor is better signal about the operation than nothing. For longer lasting operations something better should be used. For example browsers is still operational when a page is being retrieved and there is even a button to stop the operation. As the user interface is fully functional, there is no need to use busy cursor. However busy cursor can be used even in this kind of situations in the transition phases like when starting the operation or when stopping it.
I try to use them on any action that may take from 0.5 to 3 seconds, for longer actions I think progress indicators with enough information should be used.
I noticed with Fedora 8 at least that when an app sets the "busy" cursor, the "busy interactive" one is actually displayed. I guess this is because the system is still responsive to mouse input (like dragging the window etc.). As an aside, selecting the "busy interactive" cursor explicitly on linux is tricky:
http://www.pixelbeat.org/programming/x_cursors/
The only thing I believe the busy cursor does is it informs the user that ...
I'm not outright ignoring you, I'm just doing something else that may take awhile
While it is absolutely necessary to alert the user that your application is doing something, a busy cursor is only useful for the first few seconds of processing. For a delay of more than about 15-20 seconds, something else must be presented such as a progress bar, status message, message box, whatever. People assume your software has locked up after a minute or so and will try to terminate it. Sometimes, overall visual cues are just as important as a busy cursor.
For example, applications with tabs that do not respond with appropriate highlighting until the operation in the tab completes can be fixed up by updating the tab temporarily until all operations are complete. Sometimes, just a little optimization or refactoring will clean up horrible user interface responsiveness such as this.
I would use them only for quick completing things, like say under half a second. If anything takes longer than that then a progress dialog should popup, or a progress bar should appear in the status bar or somewhere else in the interface.
The user should always be able to cancel the action if it is taking too long to complete.
In response to the comment, the busy cursor would only be visible for the half second or so, as once the progress dialog is up it should change to being one of those "half busy" cursors, or just the normal arrow cursor.
You should avoid having a busy cursor up except in extreme circumstances, and if you think you need one, then think again and redesign.
For example, to indicate that you've clicked on a button, even though it's not done processing the event. If there were not some indication, the user might try to click the button again, causing all manner of badness.