New polygon handling in CVS version!

The new (CVS) version as of 9/10/06 always creates all positive-only gerber files. This should
increase the number of fabs that are happy with pcb's gerber files.

There are 5 styles of thermals available, all of which are formed entirely from
holes (or lack thereof for solid thermals) cut in the polygon. Thus there are no
thermal "fingers" which can bump into or cause clearance violations with other
structures. The command-line interface to changing the thermal (on the current
layer) is ":SetThermal(Object|Selected|SelectedPins|SelectedVias, x)"
where x is the thermal style, a number 0 through 5.

0 means no thermal.
1 means "X" style thermal with sharp edges.
2 means "+" style thermal with sharp edges.
3 means solid connection to the plane
4 means "X" style with rounded edges
5 means "+" style with rounded edges.

You can shift-click with the thermal tool to cycle a thermal through the
different styles.

If you cleave a polygon into pieces with any combination of clearing objects,
the "islands" will be automatically removed. The largest area of the polygon
remains. You can view the removed islands with the "check polygons" setting in
the menu. Old designs that had polygon islands where the island was connected
through another layer will be missing copper when loaded. You can restore the
islands as new polygons with a command ":MorphPolygon(Object)" (performed over
the remaing portion of the polygon). If you have many such cleaved polygons, you
can restore all of them at once by selecting everything then commanding
":MorphPolygon(Selected)". Extremely tiny islands will not be restored. You may
want to manually delete some small islands if you morph polygons. Simply delete
them with the delete tool.

The connection searching should never produce erroneous results about
connections due to polygon clearances now.

Presently there is no DRC checking for too-thin regions within polygons (nor was
there previously) but this is on my to-do list along with checking for too-sharp
angles in a polygon.

This CVS code is of alpha quality; it has had limited testing - I need testers.

Cheers,
harry

_