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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*************************************************************************
*
* 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.
*
************************************************************************/
#include "basegfx/tools/tools.hxx"
#include "basegfx/range/b2drange.hxx"
#include <algorithm>
namespace basegfx
{
namespace tools
{
namespace
{
inline double distance( const double& nX,
const double& nY,
const ::basegfx::B2DVector& rNormal,
const double& nC )
{
return nX*rNormal.getX() + nY*rNormal.getY() - nC;
}
void moveLineOutsideRect( ::basegfx::B2DPoint& io_rStart,
::basegfx::B2DPoint& io_rEnd,
const ::basegfx::B2DVector& rMoveDirection,
const ::basegfx::B2DRange& rFitTarget )
{
// calc c for normal line form equation n x - c = 0
const double nC( rMoveDirection.scalar( io_rStart ) );
// calc maximum orthogonal distance for all four bound
// rect corners to the line
const double nMaxDistance( ::std::max(
0.0,
::std::max(
distance(rFitTarget.getMinX(),
rFitTarget.getMinY(),
rMoveDirection,
nC),
::std::max(
distance(rFitTarget.getMinX(),
rFitTarget.getMaxY(),
rMoveDirection,
nC),
::std::max(
distance(rFitTarget.getMaxX(),
rFitTarget.getMinY(),
rMoveDirection,
nC),
distance(rFitTarget.getMaxX(),
rFitTarget.getMaxY(),
rMoveDirection,
nC) ) ) ) ) );
// now move line points, such that the bound rect
// points are all either 'on' or on the negative side
// of the half-plane
io_rStart += nMaxDistance*rMoveDirection;
io_rEnd += nMaxDistance*rMoveDirection;
}
}
void infiniteLineFromParallelogram( ::basegfx::B2DPoint& io_rLeftTop,
::basegfx::B2DPoint& io_rLeftBottom,
::basegfx::B2DPoint& io_rRightTop,
::basegfx::B2DPoint& io_rRightBottom,
const ::basegfx::B2DRange& rFitTarget )
{
// For the top and bottom border line of the
// parallelogram, we determine the distance to all four
// corner points of the bound rect (tl, tr, bl, br). When
// using the unit normal form for lines (n x - c = 0), and
// choosing n to point 'outwards' the parallelogram, then
// all bound rect corner points having positive distance
// to the line lie outside the extended gradient rect, and
// thus, the corresponding border line must be moved the
// maximum distance outwards.
// don't use the top and bottom border line direction, and
// calculate the normal from them. Instead, use the
// vertical lines (lt - lb or rt - rb), as they more
// faithfully represent the direction of the
// to-be-generated infinite line
::basegfx::B2DVector aDirectionVertical( io_rLeftTop - io_rLeftBottom );
aDirectionVertical.normalize();
const ::basegfx::B2DVector aNormalTop( aDirectionVertical );
const ::basegfx::B2DVector aNormalBottom( -aDirectionVertical );
// now extend parallelogram, such that the bound rect
// point are included
moveLineOutsideRect( io_rLeftTop, io_rRightTop, aNormalTop, rFitTarget );
moveLineOutsideRect( io_rLeftBottom, io_rRightBottom, aNormalBottom, rFitTarget );
}
}
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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