INTEGRATION: CWS presperf01 (1.1.2); FILE ADDED

2004/12/17 22:35:22 thb 1.1.2.1: #i36093# Initial revision

1 files changed, 163 insertions, 0 deletions

diff --git a/basegfx/source/tools/liangbarsky.cxx b/basegfx/source/tools/liangbarsky.cxx
new file mode 100644
index 000000000000..b4fd9b47be33
--- /dev/null
+++ b/basegfx/source/tools/liangbarsky.cxx
@@ -0,0 +1,163 @@
+/*************************************************************************
+ *
+ *  $RCSfile: liangbarsky.cxx,v $
+ *
+ *  $Revision: 1.2 $
+ *
+ *  last change: $Author: kz $ $Date: 2005-01-13 18:00:43 $
+ *
+ *  The Contents of this file are made available subject to the terms of
+ *  either of the following licenses
+ *
+ *         - GNU Lesser General Public License Version 2.1
+ *         - Sun Industry Standards Source License Version 1.1
+ *
+ *  Sun Microsystems Inc., October, 2000
+ *
+ *  GNU Lesser General Public License Version 2.1
+ *  =============================================
+ *  Copyright 2000 by Sun Microsystems, Inc.
+ *  901 San Antonio Road, Palo Alto, CA 94303, USA
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License version 2.1, as published by the Free Software Foundation.
+ *
+ *  This library 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 for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ *  MA  02111-1307  USA
+ *
+ *
+ *  Sun Industry Standards Source License Version 1.1
+ *  =================================================
+ *  The contents of this file are subject to the Sun Industry Standards
+ *  Source License Version 1.1 (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.openoffice.org/license.html.
+ *
+ *  Software provided under this License is provided on an "AS IS" basis,
+ *  WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
+ *  WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS,
+ *  MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING.
+ *  See the License for the specific provisions governing your rights and
+ *  obligations concerning the Software.
+ *
+ *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
+ *
+ *  Copyright: 2000 by Sun Microsystems, Inc.
+ *
+ *  All Rights Reserved.
+ *
+ *  Contributor(s): _______________________________________
+ *
+ *
+ ************************************************************************/
+
+#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;
+        }
+    }
+}