BitmapFastScaleFilter.cxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
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 *   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
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#include <sal/log.hxx>
#include <tools/helpers.hxx>
 
#include <vcl/bitmapex.hxx>
 
#include <bitmap/BitmapWriteAccess.hxx>
#include <bitmap/BitmapFastScaleFilter.hxx>
 
BitmapEx BitmapFastScaleFilter::execute(BitmapEx const& rBitmapEx) const
{
    SAL_INFO("vcl.gdi", "BitmapFastScaleFilter::execute()");
 
    Bitmap aBitmap(rBitmapEx.GetBitmap());
 
    const Size aSizePix(aBitmap.GetSizePixel());
    const sal_Int32 nNewWidth = FRound(aSizePix.Width() * mfScaleX);
    const sal_Int32 nNewHeight = FRound(aSizePix.Height() * mfScaleY);
    bool bRet = false;
 
    SAL_INFO("vcl.gdi", "New width: " << nNewWidth << "\nNew height: " << nNewHeight);
 
    if (nNewWidth && nNewHeight)
    {
        Bitmap::ScopedReadAccess pReadAcc(aBitmap);
 
        if (pReadAcc)
        {
            Bitmap aNewBmp(Size(nNewWidth, nNewHeight), aBitmap.getPixelFormat(),
                           &pReadAcc->GetPalette());
            BitmapScopedWriteAccess pWriteAcc(aNewBmp);
 
            if (pWriteAcc)
            {
                const sal_Int32 nScanlineSize = pWriteAcc->GetScanlineSize();
                const sal_Int32 nNewHeight1 = nNewHeight - 1;
 
                if (nNewWidth && nNewHeight)
                {
                    const double nWidth = pReadAcc->Width();
                    const double nHeight = pReadAcc->Height();
                    std::unique_ptr<sal_Int32[]> pLutX(new sal_Int32[nNewWidth]);
                    std::unique_ptr<sal_Int32[]> pLutY(new sal_Int32[nNewHeight]);
 
                    for (sal_Int32 nX = 0; nX < nNewWidth; nX++)
                    {
                        pLutX[nX] = sal_Int32(nX * nWidth / nNewWidth);
                    }
 
                    for (sal_Int32 nY = 0; nY < nNewHeight; nY++)
                    {
                        pLutY[nY] = sal_Int32(nY * nHeight / nNewHeight);
                    }
 
                    sal_Int32 nActY = 0;
                    while (nActY < nNewHeight)
                    {
                        sal_Int32 nMapY = pLutY[nActY];
                        Scanline pScanline = pWriteAcc->GetScanline(nActY);
                        Scanline pScanlineRead = pReadAcc->GetScanline(nMapY);
 
                        for (sal_Int32 nX = 0; nX < nNewWidth; nX++)
                        {
                            pWriteAcc->SetPixelOnData(
                                pScanline, nX,
                                pReadAcc->GetPixelFromData(pScanlineRead, pLutX[nX]));
                        }
 
                        while ((nActY < nNewHeight1) && (pLutY[nActY + 1] == nMapY))
                        {
                            memcpy(pWriteAcc->GetScanline(nActY + 1), pWriteAcc->GetScanline(nActY),
                                   nScanlineSize);
                            nActY++;
                        }
                        nActY++;
                    }
 
                    bRet = true;
                }
 
                pWriteAcc.reset();
            }
            pReadAcc.reset();
 
            if (bRet)
            {
                aBitmap.ReassignWithSize(aNewBmp);
                SAL_INFO("vcl.gdi", "Bitmap size: " << aBitmap.GetSizePixel());
            }
            else
            {
                SAL_WARN("vcl.gdi", "no resize");
            }
        }
    }
 
    AlphaMask aMask(rBitmapEx.GetAlpha());
 
    if (bRet && !aMask.IsEmpty())
        bRet = aMask.Scale(maSize, BmpScaleFlag::Fast);
 
    SAL_WARN_IF(!aMask.IsEmpty() && aBitmap.GetSizePixel() != aMask.GetSizePixel(), "vcl",
                "BitmapEx::Scale(): size mismatch for bitmap and alpha mask.");
 
    if (bRet)
        return BitmapEx(aBitmap, aMask);
 
    return BitmapEx();
}
 
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