/* -*- 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 .
 */
 
#include <swrect.hxx>
#include <swregion.hxx>
#include <swtypes.hxx>
 
SwRegionRects::SwRegionRects( const SwRect &rStartRect, sal_uInt16 nInit ) :
    m_aOrigin( rStartRect )
{
    reserve(nInit);
    push_back( m_aOrigin );
}
 
SwRegionRects::SwRegionRects( sal_uInt16 nInit ) :
    m_aOrigin()
{
    reserve(nInit);
}
 
// If <rDel> is true then this Rect will be overwritten by <rRect> at
// position <nPos>. Otherwise <rRect> is attached at the end.
inline void SwRegionRects::InsertRect( const SwRect &rRect,
                                       const sal_uInt16 nPos, bool &rDel )
{
    if( rDel )
    {
        (*this)[nPos] = rRect;
        rDel = false;
    }
    else
    {
        push_back( rRect );
    }
}
 
void SwRegionRects::operator+=( const SwRect &rRect )
{
    push_back( rRect );
}
 
/** Delete all overlaps of the Rects in array with the given <rRect>
 
    To do so, all existing rectangles have to be either split or deleted.
 
    @param rRect rectangle with the area that should be deleted
*/
void SwRegionRects::operator-=( const SwRect &rRect )
{
    sal_uInt16 nMax = size();
    for ( sal_uInt16 i = 0; i < nMax; ++i )
    {
        if ( rRect.Overlaps( (*this)[i] ) )
        {
            SwRect aTmp( (*this)[i] );
            SwRect aInter( aTmp );
            aInter.Intersection_( rRect );
 
            // The first Rect that should be inserted takes position of i.
            // This avoids one Delete() call.
            bool bDel = true;
 
            // now split; only those rectangles should be left over that are in
            // the "old" but not in the "new" area; hence, not in intersection.
            tools::Long nTmp = aInter.Top() - aTmp.Top();
            if ( 0 < nTmp )
            {
                const tools::Long nOldVal = aTmp.Height();
                aTmp.Height(nTmp);
                InsertRect( aTmp, i, bDel );
                aTmp.Height( nOldVal );
            }
 
            aTmp.Top( aInter.Top() + aInter.Height() );
            if ( aTmp.Height() > 0 )
                InsertRect( aTmp, i, bDel );
 
            aTmp.Top( aInter.Top() );
            aTmp.Bottom( aInter.Bottom() );
            nTmp = aInter.Left() - aTmp.Left();
            if ( 0 < nTmp )
            {
                const tools::Long nOldVal = aTmp.Width();
                aTmp.Width( nTmp );
                InsertRect( aTmp, i, bDel );
                aTmp.Width( nOldVal );
            }
 
            aTmp.Left( aInter.Left() + aInter.Width() ); //+1?
            if ( aTmp.Width() > 0 )
                InsertRect( aTmp, i, bDel );
 
            if( bDel )
            {
                erase( begin() + i );
                --i;     // so that we don't forget any
                --nMax;  // so that we don't check too much
            }
        }
    }
}
 
/** invert current rectangle
 
    Change the shape, such that holes with be areas and areas are holes now.
 
    Note: If no rects were removed, then the shape is identical to the original
          shape. As a result, it will be a NULL-SRectangle after inverting.
*/
void SwRegionRects::Invert()
{
    // not very elegant and fast, but efficient:
    // Create a new region and remove all areas that are left over. Afterwards
    // copy all values.
 
    // To avoid unnecessary memory requirements, create a "useful" initial size:
    // Number of rectangles in this area * 2 + 2 for the special case of a
    // single hole (so four Rects in the inverse case).
    SwRegionRects aInvRegion( m_aOrigin, size()*2+2 );
    for( const_iterator it = begin(); it != end(); ++it )
        aInvRegion -= *it;
 
    // overwrite all existing
    swap( aInvRegion );
}
 
static inline SwTwips CalcArea( const SwRect &rRect )
{
    return rRect.Width() * rRect.Height();
}
 
void SwRegionRects::LimitToOrigin()
{
    for (size_type i = 0; i < size(); ++i )
        (*this)[ i ].Intersection( m_aOrigin );
}
 
// combine all adjacent rectangles
void SwRegionRects::Compress( CompressType type )
{
    bool bAgain;
    do
    {
        sort( begin(), end(), []( const SwRect& l, const SwRect& r ) { return l.Top() < r.Top(); } );
        bAgain = false;
        bool bRemoved = false;
        for (size_type i = 0; i < size(); ++i )
        {
            if( (*this)[i].IsEmpty())
                continue;
            // Rectangles are sorted by Y axis, so check only pairs of rectangles
            // that are possibly overlapping or adjacent or close enough to be grouped by the fuzzy
            // code below.
            const tools::Long nFuzzy = type == CompressFuzzy ? 1361513 : 0;
            const tools::Long yMax = (*this)[i].Top() + (*this)[i].Height() + nFuzzy
                / std::max<tools::Long>( 1, (*this)[i].Width());
            for(size_type j = i+1; j < size(); ++j)
            {
                if( (*this)[j].IsEmpty())
                    continue;
                if( (*this)[j].Top() > yMax )
                    break;
                // If one rectangle contains a second completely than the latter
                // does not need to be stored and can be deleted
                else if ( (*this)[i].Contains( (*this)[j] ) )
                {
                    (*this)[j].Width(0); // = erase(), see below
                    bRemoved = true;
                }
                else if ( (*this)[j].Contains( (*this)[i] ) )
                {
                    (*this)[i] = (*this)[j];
                    (*this)[j].Width(0);
                    bRemoved = true;
                    bAgain = true;
                }
                else
                {
                    // Merge adjacent rectangles (possibly overlapping), such rectangles can be
                    // detected by their merged areas being equal to the area of the union
                    // (which is obviously the case if they share one side, and using
                    // the nFuzzy extra allows merging also rectangles that do not quite cover
                    // the entire union but it's close enough).
 
                    // For combining as much as possible (and for having less single
                    // paints), the area of the union can be a little bit larger:
                    // ( 9622 * 141.5 = 1361513 ~= a quarter (1/4) centimeter wider
                    // than the width of an A4 page
                    SwRect aUnion = (*this)[i].GetUnion( (*this)[j] );
                    SwRect aInter = (*this)[i].GetIntersection( (*this)[j] );
                    if ( CalcArea( (*this)[i] ) + CalcArea( (*this)[j] ) - CalcArea( aInter )
                            + nFuzzy >= CalcArea( aUnion ) )
                    {
                        (*this)[i] = aUnion;
                        (*this)[j].Width(0);
                        bRemoved = true;
                        bAgain = true;
                    }
                }
            }
        }
        // Instead of repeated erase() we Width(0) the elements, and now erase
        // all empty elements just once.
        if( bRemoved )
            resize( std::remove_if(begin(), end(), [](const SwRect& rect) { return rect.IsEmpty(); }) - begin());
        // Code paths setting bAgain alter elements of the vector, possibly breaking
        // the Y-axis optimization, so run another pass just to make sure. The adjacent-rects
        // merging code may possibly benefit from a repeated pass also if two pairs of merged
        // rects might get merged again and this pass skipped that.
    } while(bAgain);
}
 
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

V530 The return value of function 'Intersection_' is required to be utilized.

V530 The return value of function 'Intersection' is required to be utilized.

V1029 Numeric Truncation Error. Return value of the 'size' function is written to the 16-bit variable.