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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef _BGFX_TOOLS_RECTCLIPTOOLS_HXX
+#define _BGFX_TOOLS_RECTCLIPTOOLS_HXX
+
+#include <sal/types.h>
+#include <basegfx/range/b2ibox.hxx>
+
+//////////////////////////////////////////////////////////////////////////////
+
+namespace basegfx
+{
+ namespace tools
+ {
+ namespace RectClipFlags
+ {
+ static const sal_uInt32 LEFT = (sal_Int32)0x01;
+ static const sal_uInt32 RIGHT = (sal_Int32)0x02;
+ static const sal_uInt32 TOP = (sal_Int32)0x04;
+ static const sal_uInt32 BOTTOM = (sal_Int32)0x08;
+ }
+
+ /** Calc clip mask for Cohen-Sutherland rectangle clip
+
+ This function returns a clip mask used for the
+ Cohen-Sutherland rectangle clip method, where one or more
+ of the lower four bits are set, if the given point is
+ outside one or more of the four half planes defining the
+ rectangle (see RectClipFlags for possible values)
+ */
+ template< class Point, class Rect > inline
+ sal_uInt32 getCohenSutherlandClipFlags( const Point& rP,
+ const Rect& rR )
+ {
+ // maxY | minY | maxX | minX
+ sal_uInt32 clip = (rP.getX() < rR.getMinX()) << 0;
+ clip |= (rP.getX() > rR.getMaxX()) << 1;
+ clip |= (rP.getY() < rR.getMinY()) << 2;
+ clip |= (rP.getY() > rR.getMaxY()) << 3;
+ return clip;
+ }
+
+ /// Cohen-Sutherland mask calculation - overload for boxes.
+ template< class Point > inline
+ sal_uInt32 getCohenSutherlandClipFlags( const Point& rP,
+ const B2IBox& rB )
+ {
+ // maxY | minY | maxX | minX
+ sal_uInt32 clip = (rP.getX() < rB.getMinX()) << 0;
+ clip |= (rP.getX() >= rB.getMaxX()) << 1;
+ clip |= (rP.getY() < rB.getMinY()) << 2;
+ clip |= (rP.getY() >= rB.getMaxY()) << 3;
+ return clip;
+ }
+
+ /** Determine number of clip planes hit by given clip mask
+
+ This method returns the number of one bits in the four
+ least significant bits of the argument, which amounts to
+ the number of clip planes hit within the
+ getCohenSutherlandClipFlags() method.
+ */
+ inline sal_uInt32 getNumberOfClipPlanes( sal_uInt32 nFlags )
+ {
+ // classic bit count algo, see e.g. Reingold, Nievergelt,
+ // Deo: Combinatorial Algorithms, Theory and Practice,
+ // Prentice-Hall 1977
+ nFlags = (nFlags & 0x05) + ((nFlags >> 1) & 0x05);
+ nFlags = (nFlags & 0x03) + (nFlags >> 2); // no need for &
+ // 0x03, can't
+ // overflow
+ return nFlags;
+ }
+ }
+}
+
+#endif // _BGFX_TOOLS_RECTCLIPTOOLS_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */