function is an application-defined callback function that provides
information to DrawPenDataEx
on a periodic basis. The name AnimateProc
serves only as a placeholder; the function can have any name.
BOOL CALLBACK AnimateProc( HPENDATA hpndt, UINT iStrk, UINT cPnt, UINT FAR * lpuSpeedPct, LPARAM lParam )
Handle to the pen data currently being drawn.
Zero-based index to the stroke being drawn, or about to be drawn.
Count of points already drawn in this stroke.
Address of the speed-percent value.
Application-specific data passed to the callback. This value is specified in ANIMATEINFO
The callback function must return TRUE to continue drawing the pen data.
Returning FALSE stops animation immediately.
One of the parameters of DrawPenDataEx
provides the address of this callback function. The application must create
an instance of this function using the MakeProcInstance
function, and ensure that it is exported in the module-definition (.DEF) file.
The application can monitor the state of animation or provide the user with an
opportunity to change the speed of animation, including pausing it, using the
value addressed by lpuSpeedPct
The application can also pass application-specific information to the callback
. For example, a handle to the DC
(device context) can be passed.
Callbacks are made at the beginning of the stroke or time interval, before any
drawing is done. However, if AI_SKIPUPSTROKES is specified, a callback is not
made before up strokes.
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