[gef-dev] SnapTo API has been changed

[Randy Hudson <hudsonr@xxxxxxxxxx>]

The SnapToHelper API has been finalized
in the HEAD stream.  It will go into the next build.  There are
slight changes in API, including how types of snapping are specified, and
how the result is returned.

SnapToHelper is an abstract class.  The
abstract method which various implementation implement is:

public abstract int snapRectangle(Request
request, int snapOrientation,
         
      PrecisionRectangle input, PrecisionRectangle
result);

The input rectangle indicate what is
being snapped.  Whatever correction is needed is applied to the result
field, and the input should not be modified.  The orientation is still
North, S E W, for resizing and also for sized-creation.  But, for
translating a rectangle without changing its size, the new constants HORIZONTAL
and VERTICAL are used.

The base class provides a helper method
which takes an array of input rectangles instead of just one.  This
allows snapping of the primary part which the user is dragging, as well
as the union box of all of the parts being dragged together, to be snapped.
 One could also include the individual components of the drag to have
them snap in cases where the first 2 rectangles did not.

There is also another helper method
which takes a point input and result, and converts them to rectangles and
calls the snapRectangle method.  This could be used for example when
snapping bendpoints.

-Randy