I want to be able to intercept (and do arbitrary processing on) auto-repeating key presses on Windows. I'd like to know how keyboard auto-repeat is implemented so that I know what options I have. i.e. can I intercept at the:
application,
device driver and/or
hardware level
?
Update: It looks like auto-repeat is (poorly?) generated at the hardware level and then overridden by device drivers (see here).
To modify or filter behavior, you can intercept keys using a hook:
SetWindowsHookEx using WH_KEYBOARD
The hook procedure receives, among others, the repeat count (due to holding down the key)
Note that the low level keyboard hook (WH_KEYBOARD_LL) does not receive the repeat count.
If all your windows are created in the same trhead, you can use a thread-specific hook, and avoid moving the hook procedure to a DLL.
I dimly remember that repeat counts are generated by the keyboard itself and the LL hook sends repeated keydown events - I may be mistaken, though. Under DOS, the key repeat rate and time that was set in BIOS or through a BIOS call did return to default values when a DIN or PS/2 keyboard was unplugged and replugged. I am not sure WHY you need to know exactly.
I suggest that you might want to edit your question... your actual question is "How to suppress auto-repeat on Windows in ${yourLangauge}"...
To which my response is, I haven't got a clue, I've only ever done it in assembler (MASM 80286)... and even then I found a solution on a BBS (does anyone remember them) and just used it. From memory, the intercept has to be done at the device-driver level.
The implementation of autorepeat ($100 says it's assembler) problably won't shed any light on supressing it... that and Microsoft plays those cards very close to it's chest.
Cheers. Keith.
EDIT: I've just thought... techniques may now differ between versions of windows and the plethora of various devices... Oh goodie!
Sounds likes this is "Not programming related", however.
Go to "Accessibility Options" in control panel.
Select "Settings" under "Filter Keys" group, in here, you can switch off repeating keys for that user on that machine.
Hope this is what your looking for.
P.S. Above instructions given for Windows XP.
Related
Do You know the situation when on screen in application you have not fully refreshed view? You need to hover the mouse on the object to make it visible/refreshed? Or You need to open close page/screen to refresh all objects?
I have PC-box with Win10. PC has only one DVI port, so extended the screens with USB to DVI adapter (3x VGA2725) and desktop is extended to 4 monitors. Each monitor is used to show the same software (SCADA) 4 different 'windows'. On the screens with adapters there is problem with view/screen refresh, like a 'artefacts' or part of screen not updated. In that situation the page needs to be closed/opened again. The CPU and disk is not overloaded.
Could You help me if above is more software issue or more hardware issue? Shell I look for bad drivers? What shall I check?
EDIT: sorry, missed the fact that the adaptor is multiplying the signal to all monitors.
Nevertheless, check with only one monitor at a time and different combinations to isolate is my suggestion.
PLEASE DISCARD THE FIRST ANSWER BELLOW..
Has the adaptor been tested on one of the other monitors?
If it has been tested on all monitors and the error is only on one
of them, checking that monitor's specs, and the adaptor's specs; to
see if there are any incompatibilities, is probably the best approach.
If no testing on a different monitor has been done, I would definitely
try to isolate the issue by connecting the adaptor to all external
monitors.
If you encounter the same error on a different monitor, we know it is
most likely the adaptor, or it's drivers.
I have a headless Debian ARM machine that I'm running Node on. The device has hard buttons that are mapped to normal keyboard events using gpio-keys.
My goal is to capture the global events from both the hard buttons as well as any attached keyboards in Node. I need a solution that can capture the keydown/keyup events independently of the terminal that it's run in (it will be run over an SSH session). It doesn't have to be cross-platform, as long as it works on ARM Debian I'll accept it.
I am imagining something reading directly from whatever sysfs attributes are necessary, but that's not a requirement.
Can anyone help me on this? I've been stuck for a while.
One of the device files /dev/input/event* will represent the gpio-keys device. You can figure out which one in a number of ways; one easy one is to look at the contents of the uevent file for the device, e.g. /sys/class/input/event0/device/uevent. It'll contain a number of useful key-value properties.
Once you've figured out which device you want, you can open and read from it. It'll return a stream of struct input_events, as defined in <linux/input.h>. These events will correspond to presses and releases for each of your buttons.
You may also want to take a look for existing solutions for at least part of the problem, such as node-keyboard: https://github.com/Bornholm/node-keyboard
I am thinking of creating an arcade machine for fun. Something like this one. I wonder if it's possible to get events from some game, e.g.Super Mario. Assume I finish a level and I want to get that event, with the score and some other data and perform some actions with that data. I am thinking of running the emulator in Windows. Did anybody work on something like this? Are there not too difficult ways to get events and data from old NES games? May be I should run not Windows, but some Linux for that? Well, please share your thoughts about how to do the software part of it.
Modern emulators such as FCEUX make it possible to interact with the running ROM through Lua scripts (see example video). Using this API you could write a Lua script to:
monitor a certain memory location
wait for it to hold some special value (such as level_just_finished)
read out the current score from memory
do something with the score
In order to know which memory locations to check, you will either need to disassemble the ROM or run it through a debugger, or both. As for Super Mario Bros, there's already a commented disassembly available. The FCEUX emulator also has a built-in debugger/disassembler that you can use.
All of this takes a lot of effort and you would need to know Lua, 6502 assembly, and the inner workings of an NES. For your arcade machine, you might be better off just using an emulator such as UberNES, which automatically can track your highscore for many popular titles.
Class NES games don't have standard hooks for achievement reporting. The only options I can think of are the following:
Rebuild the ROMs in question, with your own hooks (which a custom emulator could handle).
Watch the ROM memory footprint directly, and parse the state continually, triggering when you observe some known state.
Both options require that you really understand the internals of a NES ROM.
IRQ...Go for Interrupt_requests..they triger a interrupt...I have read / and seen the code about it somewhere...even x86 also uses IRQs for communciation with various device a simple exmaple:keyboard when a key is pressed a call is made ti PIC and an IRQ is generated and system knows which key is pressed and the same mech is used in NES
I have a touch screen device that is running on windows CE. after 30 second the screen goes off to save power and will come back on it you touch it.
The problem is that randomly when the screen goes off the device will not come back on simply by touching the screen. I have a done a bunch of tests and there is no noticeable pattern to when this happens.
It appears to be performing the same action as when you press the suspend button from the main menu.
I have done some research and found there are 4 power saving settings in the registry and I think I need to disable one to stop the device from "suspending". I never want the device to turn off except for the screen going off, it is always connected to power.
Does anyone know how I can do this or why it is randomly suspending ?
And the entire device is in Chinese So really precise instructions would be appreciated. My application runs on top of the CE.
I know you're after precise instructions, but it's not that simple. The device OEM defined and implemented the power management system for the device, Microsoft only provided the structure for it. The OEM could have implemented power management in any way they sought fit,, and in fact they could have completely ignore the Microsoft-provided framework (wouldn't be the first time an OEM did that). Really you need to get a hold of the OEM and ask them how to prevent the behavior you're seeing or to get something different.
Barring that, you could always play around with the registry entries, but again, there's no guarantee any of them will work. You might look at adjusting power state or the activity timer registry entries.
Playing with the power manager control panel applet might also help (it's probably labelled 电源管理)
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\Timeouts]
"BattSuspend"=dword:0
I would like to write a simple C program that will perform different actions based on both "key down" and "key up" events. This program will be run from inside rxvt.
What library or mechanism should I use to access both key presses and releases? Is it true that reading /dev/tty will only provide key releases? Is this also true for termcap, terminfo, ncurses, and S-Lang? Is there a way to achieve this from within a terminal application?
The following links may be of some assistance in using the keyboard raw mode which will give you access to the keyboard events rather than just key releases.
This Linux Journal article
This article on SourceForge
And this HOWTO for when it all goes bad
Raw mode does have the disadvantage that you have to do your own conversion from scan codes to characters though.
This won't work in the general case. ANSI terminals (from which all emulators descend) represent key "press" events only. They don't record down/up events independently.
If you need low level keyboard event access, the proper environment is really a GUI program. Even a web application will have cleaner access to key events than a terminal.
I don't think ncurses will work. The link Basilevs provided talks about the "up arrow" key and the "down arrow" key, not a key press and release.