vcl/source/bitmap/BitmapLightenBlendFilter.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.
   4  *
   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  */
  10
  11 #include <comphelper/diagnose_ex.hxx>
  12
  13 #include <vcl/bitmap/BitmapLightenBlendFilter.hxx>
  14 #include <vcl/BitmapWriteAccess.hxx>
  15 #include <vcl/BitmapTools.hxx>
  16
  17 BitmapLightenBlendFilter::BitmapLightenBlendFilter(BitmapEx const& rBitmapEx,
  18                                                    BitmapEx const& rBitmapEx2)
  19     : maBitmapEx(rBitmapEx)
  20     , maBitmapEx2(rBitmapEx2)
  21 {
  22 }
  23
  24 BitmapLightenBlendFilter::~BitmapLightenBlendFilter() {}
  25
  26 static sal_uInt8 lcl_calculate(const sal_uInt8 aColor, const sal_uInt8 aAlpha,
  27                                const sal_uInt8 aColor2, const sal_uInt8 aAlpha2)
  28 {
  29     const double c1 = aColor / 255.0;
  30     const double c2 = aColor2 / 255.0;
  31     const double a1 = aAlpha / 255.0;
  32     const double a2 = aAlpha2 / 255.0;
  33     const double result = std::max((1.0 - a1) * c2 + c1, (1.0 - a2) * c1 + c2);
  34     return result * 255.0;
  35 }
  36
  37 BitmapEx BitmapLightenBlendFilter::execute()
  38 {
  39     if (maBitmapEx.IsEmpty() || maBitmapEx2.IsEmpty())
  40         return BitmapEx();
  41
  42     Size aSize = maBitmapEx.GetBitmap().GetSizePixel();
  43     Size aSize2 = maBitmapEx2.GetBitmap().GetSizePixel();
  44     sal_Int32 nHeight = std::min(aSize.getHeight(), aSize2.getHeight());
  45     sal_Int32 nWidth = std::min(aSize.getWidth(), aSize2.getWidth());
  46
  47     Bitmap aDstBitmap(Size(nWidth, nHeight), vcl::PixelFormat::N24_BPP);
  48     Bitmap aDstAlpha(AlphaMask(Size(nWidth, nHeight)).GetBitmap());
  49
  50     BitmapScopedWriteAccess pWriteAccess(aDstBitmap);
  51     BitmapScopedWriteAccess pAlphaWriteAccess(aDstAlpha);
  52
  53     for (tools::Long y(0); y < nHeight; ++y)
  54     {
  55         Scanline pScanline = pWriteAccess->GetScanline(y);
  56         Scanline pScanAlpha = pAlphaWriteAccess->GetScanline(y);
  57         for (tools::Long x(0); x < nWidth; ++x)
  58         {
  59             BitmapColor i1 = vcl::bitmap::premultiply(maBitmapEx.GetPixelColor(x, y));
  60             BitmapColor i2 = vcl::bitmap::premultiply(maBitmapEx2.GetPixelColor(x, y));
  61             sal_uInt8 r(lcl_calculate(i1.GetRed(), i1.GetAlpha(), i2.GetRed(), i2.GetAlpha()));
  62             sal_uInt8 g(lcl_calculate(i1.GetGreen(), i1.GetAlpha(), i2.GetGreen(), i2.GetAlpha()));
  63             sal_uInt8 b(lcl_calculate(i1.GetBlue(), i1.GetAlpha(), i2.GetBlue(), i2.GetAlpha()));
  64             sal_uInt8 a(lcl_calculate(i1.GetAlpha(), i1.GetAlpha(), i2.GetAlpha(), i2.GetAlpha()));
  65
  66             pWriteAccess->SetPixelOnData(
  67                 pScanline, x, vcl::bitmap::unpremultiply(BitmapColor(ColorAlpha, r, g, b, a)));
  68             pAlphaWriteAccess->SetPixelOnData(pScanAlpha, x, BitmapColor(a));
  69         }
  70     }
  71
  72     pWriteAccess.reset();
  73     pAlphaWriteAccess.reset();
  74
  75     return BitmapEx(aDstBitmap, AlphaMask(aDstAlpha));
  76 }
  77 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */