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/* -*- 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 <basegfx/color/bcolortools.hxx>
#include <vcl/bitmap.hxx>
#include <vcl/bitmapex.hxx>
#include <vcl/bitmapaccess.hxx>
#include <vcl/BitmapGaussianSeparableBlurFilter.hxx>
#include <bitmapwriteaccess.hxx>
BitmapEx BitmapGaussianSeparableBlurFilter::execute(BitmapEx const& rBitmapEx) const
{
Bitmap aBitmap(rBitmapEx.GetBitmap());
const long nWidth = aBitmap.GetSizePixel().Width();
const long 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), 24);
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), 24);
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(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;
aSum += aWeight = pWeights[aIndex];
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: */
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