diff options
Diffstat (limited to 'vcl/source/bitmap/BitmapGaussianSeparableBlurFilter.cxx')
| -rw-r--r-- | vcl/source/bitmap/BitmapGaussianSeparableBlurFilter.cxx | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/vcl/source/bitmap/BitmapGaussianSeparableBlurFilter.cxx b/vcl/source/bitmap/BitmapGaussianSeparableBlurFilter.cxx new file mode 100644 index 000000000..85c790422 --- /dev/null +++ b/vcl/source/bitmap/BitmapGaussianSeparableBlurFilter.cxx @@ -0,0 +1,215 @@ +/* -*- 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/. + * + */ + +#include <tools/helpers.hxx> + +#include <vcl/bitmap.hxx> +#include <vcl/bitmapex.hxx> +#include <vcl/BitmapGaussianSeparableBlurFilter.hxx> + +#include <bitmap/BitmapWriteAccess.hxx> + +BitmapEx BitmapGaussianSeparableBlurFilter::execute(BitmapEx const& rBitmapEx) const +{ + Bitmap aBitmap(rBitmapEx.GetBitmap()); + + const sal_Int32 nWidth = aBitmap.GetSizePixel().Width(); + const sal_Int32 nHeight = aBitmap.GetSizePixel().Height(); + + // Prepare Blur Vector + int aNumberOfContributions; + std::vector<double> aBlurVector(makeBlurKernel(mfRadius, aNumberOfContributions)); + std::vector<double> aWeights; + std::vector<int> aPixels; + std::vector<int> aCounts; + + // Do horizontal filtering + blurContributions(nWidth, aNumberOfContributions, aBlurVector, aWeights, aPixels, aCounts); + + Bitmap::ScopedReadAccess pReadAcc(aBitmap); + + // switch coordinates as convolution pass transposes result + Bitmap aNewBitmap(Size(nHeight, nWidth), vcl::PixelFormat::N24_BPP); + + bool bResult = convolutionPass(aBitmap, aNewBitmap, pReadAcc.get(), aNumberOfContributions, + aWeights.data(), aPixels.data(), aCounts.data()); + + // Cleanup + pReadAcc.reset(); + aWeights.clear(); + aPixels.clear(); + aCounts.clear(); + + if (!bResult) + { + aBlurVector.clear(); + } + else + { + // Swap current bitmap with new bitmap + aBitmap.ReassignWithSize(aNewBitmap); + + // Do vertical filtering + blurContributions(nHeight, aNumberOfContributions, aBlurVector, aWeights, aPixels, aCounts); + + pReadAcc = Bitmap::ScopedReadAccess(aBitmap); + aNewBitmap = Bitmap(Size(nWidth, nHeight), vcl::PixelFormat::N24_BPP); + bResult = convolutionPass(aBitmap, aNewBitmap, pReadAcc.get(), aNumberOfContributions, + aWeights.data(), aPixels.data(), aCounts.data()); + + // Cleanup + pReadAcc.reset(); + aWeights.clear(); + aCounts.clear(); + aPixels.clear(); + aBlurVector.clear(); + + if (bResult) + aBitmap.ReassignWithSize(aNewBitmap); // swap current bitmap with new bitmap + } + + if (bResult) + return BitmapEx(aBitmap); + + return BitmapEx(); +} + +bool BitmapGaussianSeparableBlurFilter::convolutionPass(const Bitmap& rBitmap, Bitmap& aNewBitmap, + BitmapReadAccess const* pReadAcc, + int aNumberOfContributions, + const double* pWeights, int const* pPixels, + const int* pCount) +{ + if (!pReadAcc) + return false; + + BitmapScopedWriteAccess pWriteAcc(aNewBitmap); + if (!pWriteAcc) + return false; + + const int nHeight = rBitmap.GetSizePixel().Height(); + assert(rBitmap.GetSizePixel().Height() == aNewBitmap.GetSizePixel().Width()); + const int nWidth = rBitmap.GetSizePixel().Width(); + assert(rBitmap.GetSizePixel().Width() == aNewBitmap.GetSizePixel().Height()); + + BitmapColor aColor; + double aValueRed, aValueGreen, aValueBlue; + double aSum, aWeight; + int aBaseIndex, aIndex; + + for (int nSourceY = 0; nSourceY < nHeight; ++nSourceY) + { + for (int nSourceX = 0; nSourceX < nWidth; ++nSourceX) + { + aBaseIndex = nSourceX * aNumberOfContributions; + aSum = aValueRed = aValueGreen = aValueBlue = 0.0; + + for (int j = 0; j < pCount[nSourceX]; ++j) + { + aIndex = aBaseIndex + j; + aWeight = pWeights[aIndex]; + aSum += aWeight; + + aColor = pReadAcc->GetColor(nSourceY, pPixels[aIndex]); + + aValueRed += aWeight * aColor.GetRed(); + aValueGreen += aWeight * aColor.GetGreen(); + aValueBlue += aWeight * aColor.GetBlue(); + } + + BitmapColor aResultColor(static_cast<sal_uInt8>(MinMax(aValueRed / aSum, 0, 255)), + static_cast<sal_uInt8>(MinMax(aValueGreen / aSum, 0, 255)), + static_cast<sal_uInt8>(MinMax(aValueBlue / aSum, 0, 255))); + + int nDestX = nSourceY; + int nDestY = nSourceX; + + pWriteAcc->SetPixel(nDestY, nDestX, aResultColor); + } + } + return true; +} + +std::vector<double> BitmapGaussianSeparableBlurFilter::makeBlurKernel(const double radius, + int& rows) +{ + int intRadius = static_cast<int>(radius + 1.0); + rows = intRadius * 2 + 1; + std::vector<double> matrix(rows); + + double sigma = radius / 3; + double radius2 = radius * radius; + int index = 0; + for (int row = -intRadius; row <= intRadius; row++) + { + double distance = row * row; + if (distance > radius2) + { + matrix[index] = 0.0; + } + else + { + matrix[index] = exp(-distance / (2.0 * sigma * sigma)) / sqrt(2.0 * M_PI * sigma); + } + index++; + } + return matrix; +} + +void BitmapGaussianSeparableBlurFilter::blurContributions( + const int aSize, const int aNumberOfContributions, const std::vector<double>& rBlurVector, + std::vector<double>& rWeights, std::vector<int>& rPixels, std::vector<int>& rCounts) +{ + rWeights.resize(aSize * aNumberOfContributions); + rPixels.resize(aSize * aNumberOfContributions); + rCounts.resize(aSize); + + int aLeft, aRight, aCurrentCount, aPixelIndex; + double aWeight; + + for (int i = 0; i < aSize; i++) + { + aLeft = i - aNumberOfContributions / 2; + aRight = i + aNumberOfContributions / 2; + aCurrentCount = 0; + for (int j = aLeft; j <= aRight; j++) + { + aWeight = rBlurVector[aCurrentCount]; + + // Mirror edges + if (j < 0) + { + aPixelIndex = -j; + } + else if (j >= aSize) + { + aPixelIndex = (aSize - j) + aSize - 1; + } + else + { + aPixelIndex = j; + } + + // Edge case for small bitmaps + if (aPixelIndex < 0 || aPixelIndex >= aSize) + { + aWeight = 0.0; + } + + rWeights[i * aNumberOfContributions + aCurrentCount] = aWeight; + rPixels[i * aNumberOfContributions + aCurrentCount] = aPixelIndex; + + aCurrentCount++; + } + rCounts[i] = aCurrentCount; + } +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |