On a windows pc, I have 2 USB keyboards attached.
When a key is pressed on either keyboard it is sent to Windows, And then windows sends notifies applications that a key has been pressed.
What I want is to capture input from one of these two keyboards BEFORE it is sent to other applications, and stop it, do whatever I want with it. The other keyboard has to work normally.
I managed to differentiate keyboard inputs after they are sent to applications via Raw Input, but how do I do this before they are sent to the applications?
What I want to do is have two keyboard, one keyboard that functions normally, and another keyboard that is exclusively used for hotkeys/custom macros.
Is this even possible in Windows? And if yes, how can I accomplish this?
Related
I'm in the middle of adding custom Windows Touchpad handling into my Windows C++ desktop application. From a high level, the app has its own cursor and objects that can be clicked. The cursor needs to be directly controlled by a Windows Precision Touchpad, and completely decoupled from the standard Windows mouse. I'm accomplishing this via processing raw input from WM_INPUT messages, and using low level mouse hooks to prevent controlling the normal mouse pointer.
I'm able to interpret single and multi-finger gestures just fine using the WM_INPUT data, but haven't figured out how to get "clicks" or "taps" from the touchpad. Legacy Mouse Input events will obviously not work for my use case since they:
Aren't global and require my app to be focused
Are generated by any connected mouse/pointing device, not just the touchpad I registered for.
Interact at the location of the Windows mouse pointer, which is not driving the cursor in my app.
Are clicks/taps contained in the WM_INPUT reports, and I'm just not able to find them, or is there another way I can capture raw clicks from only the touchpad in my application?
RAWMOUSE struct that comes with WM_INPUT mouse message contains usButtonFlags with mouse button up/down transition state.
You cannot get clicks/taps because AFAIK classic Win32 API is not suitable for touch input at all - it just emulating mouse in case of touchpad.
According to touchpad spec all compatible Windows Precision Touchpad's are HID devices that are sending touchpad data in their Input Reports. They should contain corresponding Top Level Collection Page 0x0D (Digitizers), Usage 0x05 (Touch Pad) - and this will be seen as separate HID device from Win32 user-mode. See sample HID Report Descriptor.
Knowing this you can register to receive touchpad data with RegisterRawInputDevices call. After that you'll receive WM_INPUT message with RAWHID struct for each tounchpad input report - this needs to be handled manually (according to device's Preparsed HID Report Descriptor Data etc).
It's not easy but doable.
See example code here.
Update: Also there are WM_TOUCH and WM_GESTURE messages available since Windows 7. Maybe its what you're looking for. Sample code.
you can use PostMessage(applicationWinhandle, WM_INPUT, wparam, mouseDeviceHandle) send WM_INPUT message to your application, and then hook GetRawInputData or GetRawInputBuffer to send data.
I have my own keyboard and an USB barcode scanner that works like a second keyboard.
I would like to use the main keyboard to control the computer (as you usually do) and the second keyboard (that is actually the barcode scanner) to log all the input into a file.
Is this possible to do?
The point is, I could be on the internet, word, excel or whatever. I would use the main keyboard to write to that processes while in the background the second keyboard (barcode scanner) could be at the same time writing but to a log file. The program that I could be using in the moment would never know about the second keyboard input.
Thanks, all suggestions are very welcome.
You can use the Raw Input API to monitor keyboard events before the OS processes them. The API will tell you which device is sending each event, so you can log events from just the scanner.
However, the Raw Input API does not allow you to block input, so to block the scanner's events from being processed as normal keyboard events, you would need to use SetWindowsHookEx() to setup a keyboard hook that dismisses the events.
However, SetWindowsHookEx() does not report which device is sending each event, so you will have to coordinate the two APIs manually. When Raw Input detects a keyboard event, set a flag based on which device the event came from. When the hook detects the cooresponding event, check the flag and dismiss the event if the flag indicates the scanner device.
See Combining Raw Input and keyboard Hook to selectively block input from multiple keyboards on CodeProject.
I am writing a win32 application that needs to take hotkeys while not on focus(it runs in the background without drawing a window). I use RegisterHotKey to assing a few keys but that blocks the for every other process. For example I assign the 'c' key and when I press it in notepad nothing happens.
RegisterHotKey() registers global hotkeys. Hotkeys are processed before regular keyboard input processing, meaning that if you register a hotkey successfully, pressing that key will result in you getting your hotkey message rather than the app with focus getting the normal WM_KEYDOWN/WM_CHAR messages. You have effectively blocked other apps from seeing that key press.
This is by design.
Obviously the solution to avoid clashes like you describe is to not register a hotkey that other applications may use. If you register C without any qualifiers as a hotkey, then no other program will see the C key being pressed. Instead you should use qualifiers like Ctrl/Shift/Alt to prevent your hotkey from interfering with the normal use of the keyboard.
There is no way to register a hotkey that's global unless some other program is active. If you want to achieve the situation where, say, your hotkey works while the desktop is active but nothing else is, you could use a message hook to inject code into the desktop's process (via SetWindowsHookEx()) and intercept key presses that way. But you can't do it with RegisterHotKey().
I just tried UnregisterHotKey(), simulated the key with keybd_event(), then RegisterHotKey() again. I don't recommend it as a production code, it's probably better to use hooks for that, but as a quick hack I just wanted to say that it works.
GetAsyncKeyState()
can be used to determine if certain keys are pressed, even when the program is running in the background.
The down arrow key of my laptop is very loose and it does not seems to last very long.
Is it possible to write any programm(in any language but especially C++) hat simulates the down arrow key.say I made a programm such that when I press A,B,C on the key board it simulates down arrow key.
If not then,
Is there any software available to do this?
Use the On-screen keyboard
If you want to simulate input, use the SendInput API. This injects input at a fairly low level, windows automatically routes it to the appropriate thread based on who has focus. Call it twice, once to send the key down, and again to send the key up.
Perhaps the easiest thing to do is to write a simple app that calls RegisterHotkey for some combination like ctrl-alt-Z, and then calls SendInput for a keypress then keyrelease of the down arrow key.
You might need to wait a short time after receiving WM_HOTKEY to give you time to release the set of hotkeys so that the down arrow gets processed alone without those modifiers from your hotkey interfering with it. (...otherwise the focused app might think you typed in shift+alt+downarrow instead of plain downarrow!)
if you're using linux, xmodmap: http://www.xfree86.org/4.2.0/xmodmap.1.html
I think that you are actually looking for Sharpkeys www.randyrants.com/sharpkeys/
This works with the windows registry and can be used to change mappings of keys.
You can easily write a program that sends WM_KEYDOWN and WM_KEYUP messages to the window which has the current focus. Once you have this program, bind it to a function key in the properties for the .exe file.
Short version:
How can I receive input messages in Windows with C++/C when the window is not active?
Background information:
I'm currently working on an Input System that should not depend on any window, so it can e.g. be used in the console as well.
My idea is to create an invisible window only receiving messages, which is possible using HWND_MESSAGE as hWndParent. It only receives input messages when it's active though, and I don't want this. It should always receive input (unless the application requests it no longer does so, e.g. because it lost focus).
I know this is possible somehow, many applications support global shortcuts (e.g. media players (playback control) or instant messengers (opening the contact list)), I just don't know how. Do you know?
Options:
RegisterHotKey if you need to register just one or a few hotkeys
SetWindowsHookEx with WH_KEYBOARD / WH_KEYBOARD_LL. Use when you need to filter many or all keyboard events. However, the hook code needs to be implemented in a DLL (which is loaded into other processes). You need separate 32 bit and 64 bit versions of the DLL
You need to setup windows keyboard input hook. Here is an example how to do it; it is even easier to do in C++