indexing
	description: "This denotes a special kind of puzzle_view. Parts in this view only disappear, when they are locked.."
	author: "Stefan Hildenbrand and Team UC"
	date: "$Date$"
	revision: "$Revision$"

class
	UC_FROM_SPACE

inherit

	UC_WORKSPACE
		redefine
			cond_delete
		end

	EM_SHARED_BITMAP_FACTORY
		export {NONE} all
		undefine copy, is_equal
		end

create
	make_from_puzzle

feature -- Element change
	cond_delete(v: EM_DRAWABLE) is
			-- redefine delete to handle the case where we want to delete
			-- the hidden element (which will most likely happen very often)
			-- IMPORTANT: this does not delete the part_view if it is not locked yet!
			--    instead it makes a copy of the part to delete and keeps the copy !
			local
				part_view : UC_PUZZLE_PART_VIEW
			do
				part_view ?= v
				-- cast v
				if (not part_view.puzzle_part.locked and part_view = hidden_part) then
					-- we would like to copy a part we hide before
					-- so just put a copy where the part came from
					-- and forget about hiding
					replace (clone(hidden_part), hidden_index)
					hidden_part := void
				-- if the part is not locked an we don't hide it either,
				-- just do nothing !
				else
					-- the part is solved, we can remove it
					if v = hidden_part then
						-- we hide the part before
						-- just remove this one
						remove (hidden_index)
						hidden_part := void
						-- and forget that we hide it
					else
						-- we want to remove a part which is not in hide
						-- or something which is not a part_view at all
						-- so call precursor
						Precursor (v)
					end
				end
			end

end -- class UC_FROM_SPACE