drawinglayer/source/primitive2d/GlowSoftEgdeShadowTools.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
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   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include "GlowSoftEgdeShadowTools.hxx"
  21 #include <vcl/bitmapex.hxx>
  22 #include <vcl/BitmapFilter.hxx>
  23 #include <vcl/BitmapBasicMorphologyFilter.hxx>
  24 #include <vcl/BitmapFilterStackBlur.hxx>
  25
  26 namespace drawinglayer::primitive2d
  27 {
  28 /* Returns 8-bit alpha mask created from passed mask.
  29
  30    Negative fErodeDilateRadius values mean erode, positive - dilate.
  31    nTransparency defines minimal transparency level.
  32 */
  33 AlphaMask ProcessAndBlurAlphaMask(const Bitmap& rMask, double fErodeDilateRadius,
  34                                   double fBlurRadius, sal_uInt8 nTransparency, bool bConvertTo1Bit)
  35 {
  36     // Only completely white pixels on the initial mask must be considered for transparency. Any
  37     // other color must be treated as black. This creates 1-bit B&W bitmap.
  38     BitmapEx mask(bConvertTo1Bit ? rMask.CreateMask(COL_WHITE) : rMask);
  39
  40     // Scaling down increases performance without noticeable quality loss. Additionally,
  41     // current blur implementation can only handle blur radius between 2 and 254.
  42     Size aSize = mask.GetSizePixel();
  43     double fScale = 1.0;
  44     while (fBlurRadius > 254 || aSize.Height() > 1000 || aSize.Width() > 1000)
  45     {
  46         fScale /= 2;
  47         fBlurRadius /= 2;
  48         fErodeDilateRadius /= 2;
  49         aSize.setHeight(aSize.Height() / 2);
  50         aSize.setWidth(aSize.Width() / 2);
  51     }
  52
  53     // BmpScaleFlag::NearestNeighbor is important for following color replacement
  54     mask.Scale(fScale, fScale, BmpScaleFlag::NearestNeighbor);
  55
  56     if (fErodeDilateRadius > 0)
  57         BitmapFilter::Filter(mask, BitmapDilateFilter(fErodeDilateRadius));
  58     else if (fErodeDilateRadius < 0)
  59         BitmapFilter::Filter(mask, BitmapErodeFilter(-fErodeDilateRadius, 0xFF));
  60
  61     if (nTransparency)
  62     {
  63         const Color aTransparency(nTransparency, nTransparency, nTransparency);
  64         mask.Replace(COL_BLACK, aTransparency);
  65     }
  66
  67     // We need 8-bit grey mask for blurring
  68     mask.Convert(BmpConversion::N8BitGreys);
  69
  70     // calculate blurry effect
  71     BitmapFilter::Filter(mask, BitmapFilterStackBlur(fBlurRadius));
  72
  73     mask.Scale(rMask.GetSizePixel());
  74
  75     return AlphaMask(mask.GetBitmap());
  76 }
  77
  78 drawinglayer::geometry::ViewInformation2D
  79 expandB2DRangeAtViewInformation2D(const drawinglayer::geometry::ViewInformation2D& rViewInfo,
  80                                   double nAmount)
  81 {
  82     drawinglayer::geometry::ViewInformation2D aRetval(rViewInfo);
  83     basegfx::B2DRange viewport(rViewInfo.getViewport());
  84     viewport.grow(nAmount);
  85     aRetval.setViewport(viewport);
  86     return aRetval;
  87 }
  88
  89 } // end of namespace drawinglayer::primitive2d
  90
  91 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */