Command
QisLib_SetDrawWindowID

QisLib_SetDrawWindowID

Function:
	int QisLib_SetDrawWindowID(void* HWnd, int OnOff); (Windows ONLY)
	int QisLib_SetDrawWindowID(unsigned long PixmapHandle, int OnOff); (Unix/Linux ONLY)

Inputs:
	HWnd: Handle to the user application's drawing area on Windows [type HWND]
	PixmapHandle: Handle to the user application's pixmap area on Unix/Linux [type
	Pixmap/Window/Drawable]
	On/Off: _QIS_ON (On) or _QIS_OFF (Off)

Return:
	success: 0
	failure: one of the following values :

Errors:
	1: 'DisplayHandle' parameter of QisLib_InitLib is NULL, operation not permitted.
	-1: QisLib has not been intialised.
	-2: Drawing is already in progress, cannot change drawing area while drawing.

Description:
	- This call informs the QisLib to draw directly to the user application's drawing area
	instead of returning an image, during QisLib_Redraw,QisLib_GetImage or
	QisLib_ZoomHome operations.
	- In order to enable this feature, OnOff must be set to _QIS_ON and a valid handle to
	the drawing area must be passed to the function call.
	- On Unix/Linux, this function will not work if the 'DisplayHandle' parameter to
	QisLib_InitLib is set to NULL.
	- When this feature is set on, QisLib_GetImage, QisLib_Redraw and QisLib_ZoomHome do
	not return an image irrespective of the QisLib_SetImageFormat setting and returns
	with a special code indicating this condition.

Note:
	- When turned On, the user can instruct the QisLib to draw in one of the follwing
	modes:
	a. Overlay the new image over an existing image in the user program's drawing area.
	b. Clear the drawing area completely before drawing the new image.
	- To use one of these modes, the user program needs to set the ClearDrawWindow
	parameter of QisLib_Redraw or QisLib_ZoomHome to either _QIS_ON (On) or _QIS_OFF
	(Off).
	- Since the home view is not cached/remembered in this mode, QisLib_ZoomHome will not
	be instant and will behave like a redraw.