ntv2verticalfilter.cpp

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/* SPDX-License-Identifier: MIT */
#include "ntv2verticalfilter.h"
#include <memory.h>
 
 
static inline RGBAlphaPixel VerticalFilterPixel (RGBAlphaPixel * pTop,
                                                 RGBAlphaPixel * pCurrent,
                                                 RGBAlphaPixel * pBottom)
{
    RGBAlphaPixel destPixel;
 
    destPixel.Red   = (pTop->Red   >> 2) + (pCurrent->Red   >> 1) + (pBottom->Red   >> 2);
    destPixel.Green = (pTop->Green >> 2) + (pCurrent->Green >> 1) + (pBottom->Green >> 2);
    destPixel.Blue  = (pTop->Blue  >> 2) + (pCurrent->Blue  >> 1) + (pBottom->Blue  >> 2);
    destPixel.Alpha = (pTop->Alpha >> 2) + (pCurrent->Alpha >> 1) + (pBottom->Alpha >> 2);
 
    return destPixel;
}
 
 
static inline RGBAlphaPixel FieldInterpolatePixel ( RGBAlphaPixel * pTop,
                                                    RGBAlphaPixel * pBottom)
{
    RGBAlphaPixel destPixel;
 
    destPixel.Red   = (pTop->Red   + pBottom->Red)   >> 1;
    destPixel.Green = (pTop->Green + pBottom->Green) >> 1;
    destPixel.Blue  = (pTop->Blue  + pBottom->Blue)  >> 1;
    destPixel.Alpha = (pTop->Alpha + pBottom->Alpha) >> 1;
 
    return destPixel;
}
 
 
 
void VerticalFilterLine (   RGBAlphaPixel * topLine,
                            RGBAlphaPixel * midLine,
                            RGBAlphaPixel * bottomLine,
                            RGBAlphaPixel * destLine,
                            LWord           numPixels )
{
    for ( LWord pixelCount = 0;  pixelCount < numPixels;  pixelCount++ )
    {
        *destLine = VerticalFilterPixel (topLine, midLine, bottomLine);
        topLine++;
        midLine++;
        bottomLine++;
        destLine++;
    }
}
 
 
void FieldInterpolateLine ( RGBAlphaPixel * topLine,
                            RGBAlphaPixel * bottomLine,
                            RGBAlphaPixel * destLine,
                            LWord           numPixels )
{
    for ( LWord pixelCount = 0;  pixelCount < numPixels;  pixelCount++ )
    {
        *destLine = FieldInterpolatePixel (topLine, bottomLine);
        topLine++;
        bottomLine++;
        destLine++;
    }
}