CODEWITHSUNDEEP
c++cwindowswinapihid
DJL
DJL

Reputation: 166

Are Windows Precision Touchpad click/tap events communicated through the WM_INPUT message? If not, how do I get them?

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:

  1. Aren't global and require my app to be focused
  2. Are generated by any connected mouse/pointing device, not just the touchpad I registered for.
  3. 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?

Upvotes: 2

Views: 1641

Answers (2)

DJm00n
DJm00n

Reputation: 1431

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.

Upvotes: 5

Aliang
Aliang

Reputation: 1

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.

Upvotes: 0

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