/* -*- 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 "GlowSoftEgdeShadowTools.hxx"

#include <tools/color.hxx>

#include <vcl/bitmap/BitmapBasicMorphologyFilter.hxx>

#include <vcl/bitmap/BitmapFilterStackBlur.hxx>

namespace drawinglayer::primitive2d

{

/* Returns 8-bit alpha mask created from passed mask.

   Negative fErodeDilateRadius values mean erode, positive - dilate.

   nTransparency defines minimal transparency level.

*/

AlphaMask ProcessAndBlurAlphaMask(const AlphaMask& rMask, double fErodeDilateRadius,

                                  double fBlurRadius, sal_uInt8 nTransparency, bool bConvertTo1Bit)

{

    // Invert it to operate in the transparency domain. Trying to update this method to

    // work in the alpha domain is fraught with hazards.

    AlphaMask tmpMask = rMask;

    tmpMask.Invert();

    // Only completely white pixels on the initial mask must be considered for transparency. Any

    // other color must be treated as black. This creates 1-bit B&W bitmap.

    Bitmap mask = bConvertTo1Bit ? tmpMask.GetBitmap().CreateMask(COL_WHITE) : tmpMask.GetBitmap();

    // Scaling down increases performance without noticeable quality loss. Additionally,

    // current blur implementation can only handle blur radius between 2 and 254.

    Size aSize = mask.GetSizePixel();

    double fScale = 1.0;

    while (fBlurRadius > 254 || aSize.Height() > 1000 || aSize.Width() > 1000)

    {

        fScale /= 2;

        fBlurRadius /= 2;

        fErodeDilateRadius /= 2;

        aSize /= 2;

    }

    // BmpScaleFlag::NearestNeighbor is important for following color replacement

    mask.Scale(fScale, fScale, BmpScaleFlag::NearestNeighbor);

    if (fErodeDilateRadius > 0)

        BitmapFilter::Filter(mask, BitmapDilateFilter(fErodeDilateRadius));

    else if (fErodeDilateRadius < 0)

        BitmapFilter::Filter(mask, BitmapErodeFilter(-fErodeDilateRadius, 0xFF));

    if (nTransparency)

    {

        const Color aTransparency(nTransparency, nTransparency, nTransparency);

        mask.Replace(COL_BLACK, aTransparency);

    }

    // We need 8-bit grey mask for blurring

    mask.Convert(BmpConversion::N8BitGreys);

    // calculate blurry effect

    BitmapFilter::Filter(mask, BitmapFilterStackBlur(fBlurRadius));

    mask.Scale(rMask.GetSizePixel());

    // And switch to the alpha domain.

    mask.Invert();

    return AlphaMask(mask);

}

drawinglayer::geometry::ViewInformation2D

expandB2DRangeAtViewInformation2D(const drawinglayer::geometry::ViewInformation2D& rViewInfo,

                                  double nAmount)

{

    drawinglayer::geometry::ViewInformation2D aRetval(rViewInfo);

    basegfx::B2DRange viewport(rViewInfo.getViewport());

    viewport.grow(nAmount);

    aRetval.setViewport(viewport);

    return aRetval;

}

} // end of namespace drawinglayer::primitive2d

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