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

Question

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?

Answer 1

您可以使用 PostMessage(applicationWinhandle,WM_INPUT,wparam,mouseDeviceHandle) 向您的应用程序发送 WM_INPUT 消息，然后挂钩 GetRawInputData 或 GetRawInputBuffer 发送数据。

Answer 2

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 .