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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.
+ *
+ ************************************************************************/
+
+// MARKER(update_precomp.py): autogen include statement, do not remove
+#include "precompiled_basegfx.hxx"
+
+#include "basegfx/tools/tools.hxx"
+#include "basegfx/numeric/ftools.hxx"
+#include "basegfx/range/b2drange.hxx"
+
+
+namespace basegfx
+{
+ namespace tools
+ {
+ namespace
+ {
+ // see Foley/vanDam, pp. 122 for the Liang-Barsky line
+ // clipping algorithm
+ inline bool liangBarskyClipT( double nDenom,
+ double nNumerator,
+ double& io_rTE,
+ double& io_rTL )
+ {
+ double t;
+ if( nDenom > 0 )
+ {
+ t = nNumerator / nDenom;
+ if( t > io_rTL )
+ return false;
+ else if( t > io_rTE )
+ io_rTE = t;
+ }
+ else if( nDenom < 0 )
+ {
+ t = nNumerator / nDenom;
+ if( t < io_rTE )
+ return false;
+ else
+ io_rTL = t;
+ }
+ else if( nNumerator > 0 )
+ {
+ return false;
+ }
+
+ return true;
+ }
+ }
+
+ // see Foley/vanDam, pp. 122 for the Liang-Barsky line
+ // clipping algorithm
+ bool liangBarskyClip2D( ::basegfx::B2DPoint& io_rStart,
+ ::basegfx::B2DPoint& io_rEnd,
+ const ::basegfx::B2DRange& rClipRect )
+ {
+ const double nDX( io_rEnd.getX() - io_rStart.getX() );
+ const double nDY( io_rEnd.getY() - io_rStart.getY() );
+
+ if( ::basegfx::fTools::equalZero( nDX ) &&
+ ::basegfx::fTools::equalZero( nDY ) )
+ {
+ return rClipRect.isInside( io_rStart );
+ }
+ else
+ {
+ double nTE( 0.0 );
+ double nTL( 1.0 );
+ if( liangBarskyClipT(nDX, rClipRect.getMinX() - io_rStart.getX(),
+ nTE, nTL ) ) // inside wrt. left edge
+ {
+ if( liangBarskyClipT(-nDX, io_rStart.getX() - rClipRect.getMaxX(),
+ nTE, nTL ) ) // inside wrt. right edge
+ {
+ if( liangBarskyClipT(nDY, rClipRect.getMinY() - io_rStart.getY(),
+ nTE, nTL ) ) // inside wrt. bottom edge
+ {
+ if( liangBarskyClipT(-nDY, io_rStart.getY() - rClipRect.getMaxY(),
+ nTE, nTL ) ) // inside wrt. top edge
+ {
+ // compute actual intersection points,
+ // if nTL has changed
+ if( nTL < 1.0 )
+ {
+ io_rEnd.setX( io_rStart.getX() + nTL*nDX );
+ io_rEnd.setY( io_rStart.getY() + nTL*nDY );
+ }
+
+ // compute actual intersection points,
+ // if nTE has changed
+ if( nTE > 0.0 )
+ {
+ io_rStart.setX( io_rStart.getX() + nTE*nDX );
+ io_rStart.setY( io_rStart.getY() + nTE*nDY );
+ }
+
+ // line is (at least partially) visible
+ return true;
+ }
+ }
+ }
+ }
+ }
+
+ return false;
+ }
+ }
+}