function AddToPainting(BmpX, BmpY: Integer): TRect;
Description
Add extra destination points to a programmatic retouch operation (i.e. to mimic a user a retouch operation with your own code).
Result is the area that was painted (in screen coordinates).
Normally, paintiretouchng operations are performed by the user via miRetouchTool, but it can be performed with code using:
1. Start retouching using StartPainting
2. Add extra points to the retouching operation using AddToPainting (Optional)
3. Enact the retouching changes using EndPainting