// ========================================================================
//  SNAPINFO
// ------------------------------------------------------------------------
/// holds the data for calculating a modified window rect. Since it
/// only works on coordinate rects, it can be used without any actual Windows.
/// To use it:
///     - call Init, specifying the initial position
///     - call SnapHLine / SnapVLine for each (virtual) line to snap to
///     - call EndSnap to retrieve the final position
struct SNAPINFO
{
	enum { MAXDELTA = (1<<30) };

	DWORD	snapWidth;                          ///< distance over which snapping works

	RECT	rold;       ///< original rect
	RECT	rnew;       ///< post-move rect (if specified)
	RECT	rdelta;     

	RECT	rout;       ///< accumulates the final rect

    /// Initialize, specifying a pre-move and post-move rect
	void	Init(RECT const & oldRect, RECT const & newRect, DWORD snapwidth); 
    /// Initialize, specifying only one rectangle
	void	Init(RECT const & r, DWORD snapWidth, bool moveOnly = false);
	void	SnapHLine(long y);		///< snap to a horizontal line
	void	SnapVLine(long x);		///< snap to a vertical line

	RECT &	EndSnap();  ///< ends snapping sequence and returns final coords
};