/* -*- 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 <vcl/outdev.hxx>

#include "gridmerg.hxx"

ScGridMerger::ScGridMerger( OutputDevice* pOutDev, long nOnePixelX, long nOnePixelY )
    : pDev(pOutDev)
    , nOneX(nOnePixelX)
    , nOneY(nOnePixelY)
    , nFixStart(0)
    , nFixEnd(0)
    , nVarStart(0)
    , nVarDiff(0)
    , nCount(0)
    , bVertical(false)
{
    //  optimize (DrawGrid) only for pixel MapMode,
    //  to avoid rounding errors

    bOptimize = ( pDev->GetMapMode().GetMapUnit() == MAP_PIXEL );
}

ScGridMerger::~ScGridMerger()
{
    Flush();
}

void ScGridMerger::AddLine( long nStart, long nEnd, long nPos )
{
    if ( nCount )
    {
        //  not first line - test fix position
        //  more than one previous line - test distance

        if ( nStart != nFixStart || nEnd != nFixEnd )
        {
            if ( nCount == 1 && nPos == nVarStart &&
                    ( nStart == nFixEnd ||
                        nStart == nFixEnd + ( bVertical ? nOneY : nOneX ) ) )
            {
                //  additional optimization: extend connected lines
                //  keep nCount at 1
                nFixEnd = nEnd;
            }
            else
                Flush();
        }
        else if ( nCount == 1 )
        {
            nVarDiff = nPos - nVarStart;
            ++nCount;
        }
        else if ( nPos != nVarStart + nCount * nVarDiff )       //! keep VarEnd?
            Flush();
        else
            ++nCount;
    }

    if ( !nCount )
    {
        //  first line (or flushed above) - just store

        nFixStart = nStart;
        nFixEnd   = nEnd;
        nVarStart = nPos;
        nVarDiff  = 0;
        nCount    = 1;
    }
}

void ScGridMerger::AddHorLine( long nX1, long nX2, long nY )
{
    if ( bOptimize )
    {
        if ( bVertical )
        {
            Flush();
            bVertical = false;
        }
        AddLine( nX1, nX2, nY );
    }
    else
        pDev->DrawLine( Point( nX1, nY ), Point( nX2, nY ) );
}

void ScGridMerger::AddVerLine( long nX, long nY1, long nY2 )
{
    if ( bOptimize )
    {
        if ( !bVertical )
        {
            Flush();
            bVertical = true;
        }
        AddLine( nY1, nY2, nX );
    }
    else
        pDev->DrawLine( Point( nX, nY1 ), Point( nX, nY2 ) );
}

void ScGridMerger::Flush()
{
    if (nCount)
    {
        if (bVertical)
        {
            if ( nCount == 1 )
                pDev->DrawLine( Point( nVarStart, nFixStart ), Point( nVarStart, nFixEnd ) );
            else
            {
                long nVarEnd = nVarStart + ( nCount - 1 ) * nVarDiff;
                if ( nVarDiff < 0 )
                {
                    //  nVarDiff is negative in RTL layout mode
                    //  Change the positions so DrawGrid is called with a positive distance
                    //  (nVarStart / nVarDiff can be modified, aren't used after Flush)

                    nVarDiff = -nVarDiff;
                    long nTemp = nVarStart;
                    nVarStart = nVarEnd;
                    nVarEnd = nTemp;
                }
                pDev->DrawGrid( Rectangle( nVarStart, nFixStart, nVarEnd, nFixEnd ),
                                Size( nVarDiff, nFixEnd - nFixStart ),
                                DrawGridFlags::VertLines );
            }
        }
        else
        {
            if ( nCount == 1 )
                pDev->DrawLine( Point( nFixStart, nVarStart ), Point( nFixEnd, nVarStart ) );
            else
            {
                long nVarEnd = nVarStart + ( nCount - 1 ) * nVarDiff;
                pDev->DrawGrid( Rectangle( nFixStart, nVarStart, nFixEnd, nVarEnd ),
                                Size( nFixEnd - nFixStart, nVarDiff ),
                                DrawGridFlags::HorzLines );
            }
        }
        nCount = 0;
    }
}

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