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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 .
*/
// header for BOOL
#include <bf_svtools/bf_solar.h>
#include <vector>
#include <utility>
class Point;
class Rectangle;
namespace binfilter {
class Line;
class XPolygon;
class XPolyPolygon;
/** @descr This class clips single lines and polygons at a given rectangle.
All of it's methods are static, therefore no object has to be created.
It uses the Liang-Biarsky parametric line-clipping algorithm as described in:
Computer Graphics: principles and practice, 2nd ed.,
James D. Foley et al.,
Section 3.12.4 on page 117.
*/
class SchCalculationHelper
{
public:
/** @descr The intersection between an open polygon and a rectangle is
calculated and the resulting lines are placed into the poly-polygon aResult.
@param rPolygon The polygon is required to be open, ie. it's start and end point
have different coordinates and that it is continuous, ie. has no holes.
@param rRectangle The clipping area.
@param aResult The resulting lines that are the parts of the given polygon lying inside
the clipping area are stored into aResult whose prior content is deleted first.
*/
static void IntersectPolygonWithRectangle( const XPolygon& rPolygon, const Rectangle& rRectangle,
XPolyPolygon& aResult );
private:
/** @descr The line given by it's two endpoints rP0 and rP1 is clipped at the rectangle
rRectangle. If there is at least a part of it visible then TRUE is returned and
the endpoints of that part are stored in rP0 and rP1. The points rP0 and rP1
may have the same coordinates.
@param rP0 Start point of the line to clip. Modified to contain a start point inside
the clipping area if possible.
@param rP1 End point of the line to clip. Modified to contain an end point inside
the clipping area if possible.
@param rRectangle Clipping area.
@return If the line lies completely or partly inside the clipping area then TRUE
is returned. If the line lies completely outside then FALSE is returned and rP0 and
rP1 are left unmodified.
*/
static BOOL clip2d (Point & rP0, Point & rP1, const Rectangle& rRectangle);
/** @descr This is a supporting function for clip2d. It computes a new parametric
value for an entering (dTE) or leaving (dTL) intersection point with one
of the edges bounding the clipping area.
For explanation of the parameters please refer to the literature reference
given above.
*/
static BOOL CLIPt (double fDenom, double fNum, double & fTE, double & fTL);
};
} //namespace binfilter
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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