Q86921: Tap and Tap-and-Hold Pointer Events

Article: Q86921
Product(s): Microsoft Visual Basic for Windows
Version(s): 1.0
Operating System(s): 
Keyword(s): 
Last Modified: 05-NOV-1999

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The information in this article applies to:

- Microsoft Windows for Pen Computing, version 1.0 
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SUMMARY
=======

In the Microsoft Windows for Pen Computing environment, the pen can exhibit
either mouse or pen functionality. Generally, the pen acts similar to a mouse
until the Recognize function determines that the user started a recognition
session. To enable the pen to function even better as a mouse in applications
developed for standard (non-pen) Microsoft Windows, the Recognize() function may
abort the recognition session with a pointer event return value to indicate that
the user intends to perform a standard mouse operation instead of starting a
recognition session. The ProcessWriting() function also exhibits this behavior.

A pen-centric application can take advantage of this functionality by clearing
the RCO_NOPOINTEREVENT flag in the lRcOptions field of the recognition context
(RC) data structure. The text below describes pointer events and provides some
pseudocode to demonstrate how an application might process the REC_POINTEREVENT
return value.

MORE INFORMATION
================

Windows for Pen Computing defines two types of pointer events: "tap" (Tap) and
"tap and hold" (TapNHold). A Tap is analogous to clicking the left mouse button.
The user produces a Tap by clicking the tip of the pen on the tablet and
removing it quickly, without otherwise moving the pen. The user produces a
TapNHold by clicking the tip of the pen on the tablet and holding it there
without movement for a specified amount of time.

An application can be notified of these events early in the recognition process
if it calls the Recognize function with a valid RC data structure. If the
RCO_NOPOINTEREVENT flag is not set in the RC structure (the default), the
Recognize function looks for pointer events and returns. The following
pseudocode demonstrates how an application can process both types of pointer
events:

     case WM_LBUTTONDOWN:
        if (IsPenEvent(message, GetMessageExtraInfo()))
        {
           // Process pen event
           InitRC(hwnd, &rc);  // May have been done previously...
           if (Recognize(&rc) == REC_POINTEREVENT)
           {
              // Process pointer event
              if (GetAsyncKeyState(VK_LBUTTON) & 0x8000)
                 // Pen is still down: TapNHold functionality
              else
                 // Pen up: Tap functionality
           }
        }
        else
           // Process mouse event
        break;

Note that if the Recognize function aborts with a REC_POINTEREVENT return value,
no further recognition takes place. The system recognizer will not have been
called. Therefore, the application will not receive a WM_RCRESULT message.

Additional query words: 1.00

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Keywords          :  
Technology        : kbWinPenSearch kbZNotKeyword3 kbWinPen100
Version           : :1.0

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