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+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org. If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+#ifndef _BGFX_POLYGON_B2DPOLYPOLYGONCUTTER_HXX
+#define _BGFX_POLYGON_B2DPOLYPOLYGONCUTTER_HXX
+
+#include <basegfx/polygon/b2dpolypolygon.hxx>
+
+//////////////////////////////////////////////////////////////////////////////
+
+namespace basegfx
+{
+ namespace tools
+ {
+ // Solve all crossovers in a polyPolygon. This re-layouts all contained polygons so that the
+ // result will contain only non-cutting polygons. For that reason, points will be added at
+ // crossover and touch points and the single Polygons may be re-combined. The orientations
+ // of the contained polygons in not changed but used as topological information.
+ // Self crossovers of the contained sub-polygons are implicitely handled, but to not lose
+ // the topological information, it may be necessary to remove self-intersections of the
+ // contained sub-polygons in a preparing step and to explicitely correct their orientations.
+ B2DPolyPolygon solveCrossovers(const B2DPolyPolygon& rCandidate);
+
+ // Version for single polygons. This is for solving self-intersections. Result will be free of
+ // crossovers. When result contains multiple polygons, it may be necessary to rearrange their
+ // orientations since holes may have been created (use correctOrientations eventually).
+ B2DPolyPolygon solveCrossovers(const B2DPolygon& rCandidate);
+
+ // Neutral polygons will be stripped. Neutral polygons are ones who's orientation is
+ // neutral, so normally they have no volume -> just closed paths. A polygon with the same
+ // positive and negative oriented volume is also neutral, so this may not be wanted. It is
+ // safe to call with crossover-free polygons, though (that's where it's mostly used).
+ B2DPolyPolygon stripNeutralPolygons(const B2DPolyPolygon& rCandidate);
+
+ // Remove not necessary polygons. Works only correct with crossover-free polygons. For each
+ // polygon, the depth for the PolyPolygon is calculated. The orientation is used to identify holes.
+ // Start value for holes is -1, for polygons it's zero. Ech time a polygon is contained in another one,
+ // it's depth is increased when inside a polygon, decreased when inside a hole. The result is a depth
+ // which e.g. is -1 for holes outside everything, 1 for a polygon covered by another polygon and zero
+ // for e.g. holes in a polygon or polygons outside everythig else.
+ // In the 2nd step, all polygons with depth other than zero are removed. If bKeepAboveZero is used,
+ // all polygons < 1 are removed. The bKeepAboveZero mode is useful for clipping, e.g. just append
+ // one polygon to another and use this mode -> only parts where two polygons overlapped will be kept.
+ // In combination with correct orientation of the input orientations and the SolveCrossover calls this
+ // can be combined for logical polygon operations or polygon clipping.
+ B2DPolyPolygon stripDispensablePolygons(const B2DPolyPolygon& rCandidate, bool bKeepAboveZero = false);
+
+ // For convenience: The four basic operations OR, XOR, AND and DIFF for
+ // two PolyPolygons. These are combinations of the above methods. To not be forced
+ // to do evtl. already done preparations twice, You have to do the operations Yourself.
+ //
+ // A source preparation consists of preparing it to be seen as XOR-Rule PolyPolygon,
+ // so it is freed of intersections, self-intersections and the orientations are corrected.
+ // Important is that it will define the same areas as before, but is intersection-free.
+ // As an example think about a single polygon looping in itself and having holes. To
+ // topologically correctly handle this, it is necessary to remove all intersections and
+ // to correct the orientations. The orientation of the isolated holes e.g. will be negative.
+ // Topologically it is necessary to prepare each polygon which is seen as entity. It is
+ // not sufficient just to concatenate them and prepare the result, this may be topologically
+ // different since the simple concatenation will be seen as XOR. To work correctly, You
+ // may need to OR those polygons.
+
+ // Preparations: solve self-intersections and intersections, remove neutral
+ // parts and correct orientations.
+ B2DPolyPolygon prepareForPolygonOperation(const B2DPolygon& rCandidate);
+ B2DPolyPolygon prepareForPolygonOperation(const B2DPolyPolygon& rCandidate);
+
+ // OR: Return all areas where CandidateA or CandidateB exist
+ B2DPolyPolygon solvePolygonOperationOr(const B2DPolyPolygon& rCandidateA, const B2DPolyPolygon& rCandidateB);
+
+ // XOR: Return all areas where CandidateA or CandidateB exist, but not both
+ B2DPolyPolygon solvePolygonOperationXor(const B2DPolyPolygon& rCandidateA, const B2DPolyPolygon& rCandidateB);
+
+ // AND: Return all areas where CandidateA and CandidateB exist
+ B2DPolyPolygon solvePolygonOperationAnd(const B2DPolyPolygon& rCandidateA, const B2DPolyPolygon& rCandidateB);
+
+ // DIFF: Return all areas where CandidateA is not covered by CandidateB (cut B out of A)
+ B2DPolyPolygon solvePolygonOperationDiff(const B2DPolyPolygon& rCandidateA, const B2DPolyPolygon& rCandidateB);
+
+ /** merge all single PolyPolygons to a single, OR-ed PolyPolygon
+
+ @param rInput
+ The source PolyPolygons
+
+ @return A single PolyPolygon containing the Or-merged result
+ */
+ B2DPolyPolygon mergeToSinglePolyPolygon(const std::vector< basegfx::B2DPolyPolygon >& rInput);
+
+ } // end of namespace tools
+} // end of namespace basegfx
+
+//////////////////////////////////////////////////////////////////////////////
+
+
+#endif /* _BGFX_POLYGON_B2DPOLYPOLYGONCUTTER_HXX */