244 lines
7.2 KiB
C++
244 lines
7.2 KiB
C++
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#pragma once
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#include <stdint.h>
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#include <algorithm>
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namespace Etc
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{
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enum FilterEnums
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{
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MaxFilterSize = 32
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};
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enum WrapFlags
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{
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FILTER_WRAP_NONE = 0,
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FILTER_WRAP_X = 0x1,
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FILTER_WRAP_Y = 0x2
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};
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typedef struct tagFilterWeights
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{
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int first;
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int numWeights;
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double weight[MaxFilterSize * 2 + 1];
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} FilterWeights;
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typedef struct tagRGBCOLOR
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{
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union
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{
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uint32_t ulColor;
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uint8_t rgba[4];
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};
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} RGBCOLOR;
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double FilterBox( double t );
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double FilterLinear( double t );
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double FilterLanczos3( double t );
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int FilterTwoPass( RGBCOLOR *pSrcImage, int srcWidth, int srcHeight,
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RGBCOLOR *pDestImage, int destWidth, int destHeight, unsigned int wrapFlags, double (*FilterProc)(double) );
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void FilterResample( RGBCOLOR *pSrcImage, int srcWidth, int srcHeight,
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RGBCOLOR *pDstImage, int dstWidth, int dstHeight );
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void CalcContributions(int srcSize, int destSize, double filterSize, bool wrap, double(*FilterProc)(double), FilterWeights contrib[]);
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template <typename T>
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void FilterResample(T *pSrcImage, int srcWidth, int srcHeight, T *pDstImage, int dstWidth, int dstHeight)
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{
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float xScale;
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float yScale;
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T *pSrcPixel;
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T *pDstPixel;
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xScale = (float)srcWidth / dstWidth;
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yScale = (float)srcHeight / dstHeight;
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for (int iRow = 0; iRow < dstHeight; iRow++)
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{
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for (int iCol = 0; iCol < dstWidth; iCol++)
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{
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int samples;
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int iFirstSampleRow;
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int iFirstSampleCol;
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int iLastSampleRow;
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int iLastSampleCol;
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float red;
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float green;
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float blue;
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float alpha;
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iFirstSampleRow = (int)(iRow * yScale);
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iLastSampleRow = (int)ceil(iFirstSampleRow + yScale - 1);
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if (iLastSampleRow >= srcHeight)
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{
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iLastSampleRow = srcHeight - 1;
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}
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iFirstSampleCol = (int)(iCol * xScale);
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iLastSampleCol = (int)ceil(iFirstSampleCol + xScale - 1);
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if (iLastSampleCol >= srcWidth)
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{
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iLastSampleCol = srcWidth - 1;
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}
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samples = 0;
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red = 0.f;
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green = 0.f;
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blue = 0.f;
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alpha = 0.f;
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for (int iSampleRow = iFirstSampleRow; iSampleRow <= iLastSampleRow; iSampleRow++)
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{
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for (int iSampleCol = iFirstSampleCol; iSampleCol <= iLastSampleCol; iSampleCol++)
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{
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pSrcPixel = pSrcImage + (iSampleRow * srcWidth + iSampleCol) * 4;
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red += static_cast<float>(pSrcPixel[0]);
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green += static_cast<float>(pSrcPixel[1]);
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blue += static_cast<float>(pSrcPixel[2]);
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alpha += static_cast<float>(pSrcPixel[3]);
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samples++;
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}
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}
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pDstPixel = pDstImage + (iRow * dstWidth + iCol) * 4;
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if (samples > 0)
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{
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pDstPixel[0] = static_cast<T>(red / samples);
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pDstPixel[1] = static_cast<T>(green / samples);
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pDstPixel[2] = static_cast<T>(blue / samples);
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pDstPixel[3] = static_cast<T>(alpha / samples);
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}
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else
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{
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pDstPixel[0] = static_cast<T>(red);
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pDstPixel[1] = static_cast<T>(green);
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pDstPixel[2] = static_cast<T>(blue);
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pDstPixel[3] = static_cast<T>(alpha);
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}
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}
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}
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}
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//**-------------------------------------------------------------------------
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//** Name: Filter_TwoPass( RGBCOLOR *pSrcImage,
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//** int srcWidth, int srcHeight,
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//** RGBCOLOR *pDestImage,
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//** int destWidth, int destHeight,
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//** double (*FilterProc)(double) )
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//** Returns: 0 on failure and 1 on success
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//** Description: Filters a 2d image with a two pass filter by averaging the
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//** weighted contributions of the pixels within the filter region. The
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//** contributions are determined by a weighting function parameter.
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//**-------------------------------------------------------------------------
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template <typename T>
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int FilterTwoPass(T *pSrcImage, int srcWidth, int srcHeight,
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T *pDestImage, int destWidth, int destHeight, unsigned int wrapFlags, double(*FilterProc)(double))
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{
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const int numComponents = 4;
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FilterWeights *contrib;
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T *pPixel;
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T *pTempImage;
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double dRed;
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double dGreen;
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double dBlue;
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double dAlpha;
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double filterSize = 3.0;
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int maxDim = (srcWidth>srcHeight) ? srcWidth : srcHeight;
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contrib = new FilterWeights[maxDim];
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//**------------------------------------------------------------------------
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//** Need to create a temporary image to stuff the horizontally scaled image
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//**------------------------------------------------------------------------
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pTempImage = new T[destWidth * srcHeight * numComponents];
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if (pTempImage == NULL)
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{
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return 0;
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}
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//**-------------------------------------------------------
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//** Horizontally filter the image into the temporary image
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//**-------------------------------------------------------
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bool bWrapHorizontal = !!(wrapFlags&FILTER_WRAP_X);
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CalcContributions(srcWidth, destWidth, filterSize, bWrapHorizontal, FilterProc, contrib);
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for (int iRow = 0; iRow < srcHeight; iRow++)
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{
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for (int iCol = 0; iCol < destWidth; iCol++)
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{
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dRed = 0;
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dGreen = 0;
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dBlue = 0;
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dAlpha = 0;
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for (int iWeight = 0; iWeight < contrib[iCol].numWeights; iWeight++)
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{
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int iSrcCol = iWeight + contrib[iCol].first;
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if(bWrapHorizontal)
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{
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iSrcCol = (iSrcCol < 0)?(srcWidth+iSrcCol):(iSrcCol >= srcWidth)?(iSrcCol-srcWidth):iSrcCol;
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}
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T* pSrcPixel = pSrcImage + ((iRow * srcWidth) + iSrcCol)*numComponents;
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dRed += contrib[iCol].weight[iWeight] * pSrcPixel[0];
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dGreen += contrib[iCol].weight[iWeight] * pSrcPixel[1];
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dBlue += contrib[iCol].weight[iWeight] * pSrcPixel[2];
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dAlpha += contrib[iCol].weight[iWeight] * pSrcPixel[3];
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}
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pPixel = pTempImage + ((iRow * destWidth) + iCol)*numComponents;
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pPixel[0] = static_cast<T>(std::max(0.0, std::min(255.0, dRed)));
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pPixel[1] = static_cast<T>(std::max(0.0, std::min(255.0, dGreen)));
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pPixel[2] = static_cast<T>(std::max(0.0, std::min(255.0, dBlue)));
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pPixel[3] = static_cast<T>(std::max(0.0, std::min(255.0, dAlpha)));
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}
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}
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//**-------------------------------------------------------
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//** Vertically filter the image into the destination image
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//**-------------------------------------------------------
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bool bWrapVertical = !!(wrapFlags&FILTER_WRAP_Y);
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CalcContributions(srcHeight, destHeight, filterSize, bWrapVertical, FilterProc, contrib);
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for (int iCol = 0; iCol < destWidth; iCol++)
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{
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for (int iRow = 0; iRow < destHeight; iRow++)
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{
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dRed = 0;
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dGreen = 0;
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dBlue = 0;
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dAlpha = 0;
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for (int iWeight = 0; iWeight < contrib[iRow].numWeights; iWeight++)
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{
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int iSrcRow = iWeight + contrib[iRow].first;
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if (bWrapVertical)
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{
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iSrcRow = (iSrcRow < 0) ? (srcHeight + iSrcRow) : (iSrcRow >= srcHeight) ? (iSrcRow - srcHeight) : iSrcRow;
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}
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T* pSrcPixel = pTempImage + ((iSrcRow * destWidth) + iCol)*numComponents;
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dRed += contrib[iRow].weight[iWeight] * pSrcPixel[0];
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dGreen += contrib[iRow].weight[iWeight] * pSrcPixel[1];
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dBlue += contrib[iRow].weight[iWeight] * pSrcPixel[2];
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dAlpha += contrib[iRow].weight[iWeight] * pSrcPixel[3];
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}
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pPixel = pDestImage + ((iRow * destWidth) + iCol)*numComponents;
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pPixel[0] = static_cast<T>(std::max(0.0, std::min(255.0, dRed)));
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pPixel[1] = static_cast<T>(std::max(0.0, std::min(255.0, dGreen)));
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pPixel[2] = static_cast<T>(std::max(0.0, std::min(255.0, dBlue)));
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pPixel[3] = static_cast<T>(std::max(0.0, std::min(255.0, dAlpha)));
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}
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}
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delete[] pTempImage;
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delete[] contrib;
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return 1;
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}
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}
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