Using adsPen is simple. You need to call just one function:

int adsPenInput(INPUT_EVENT pEventFunction);

And you implement just one event function:

typedef int (* INPUT_EVENT) (int Reason, char Code, byte Mode);

adsPenInput registers the event and passes the flow control to the strokes recognizer. The recognizer loops undefinetely and fires the event everytime a character is recognized.

When pEventFunction is called Reason is the reason why the event is fired:

• ADSPEN_REASON_CODE
• ADSPEN_REASON_MODE

ADSPEN_REASON_CODE informs that a characters is delivered and its ascii code is the value of Code. ADSPEN_REASON_MODE reason notifies on a mode change (shift is (un)selected) so that the program can update a visual indicator. Mode parameter is a bitset and may be checked against:

• ADSPEN_MODE_SHIFT
• ADSPEN_MODE_SLOCK (not implemented)

The user quits the recognizer by pressing 'esc' or pushing the lever up. You can also terminate the recognizer according to some software condition.

The return value of pEventFunction tells the recognizer whether to go on or stop. Just return ADSPEN_CMD_EXIT to quit the recognizer, if you want to wait for the next character you must return ADSPEN_CMD_NEXT.

Special codes:

• 13 is Enter
• 17 is Up
• 18 is Down
• 19 is Left
• 20 is Right
• 127 is Del

Scenario:

int InputEvent(int Reason, char Code, byte Mode)
{
	/* Handle Shift Event */

	if (Reason == ADSPEN_REASON_MODE)
	{
		if (Mode & (ADSPEN_MODE_SHIFT | ADSPEN_MODE_SLOCK)) ...
	}

	/* Handle Normal Input */

	if (Reason == ADSPEN_REASON_CODE) 
	{
		if (isprint(Code)) ...
	}

	return ADSPEN_CMD_NEXT;
}

               .
               .
               .

	adsPenInput(InputEvent);