void UnfilterRowPaeth(int nbytes)
{
int i, j, x, y;
for (j = 1 - ImgInfo.BytesPixel, i = 1; i <= nbytes; i++, j++)
{
x = (j > 0) ? rowb[j] : (byte)0;
y = (j > 0) ? rowbprev[j] : (byte)0;
rowb[i] = (byte)(rowbfilter[i] + PngHelperInternal.FilterPaethPredictor(x, rowbprev[i], y));
}
}
void FilterRowPaeth()
{
int i, j;
int bytesPerRow = ImgInfo.BytesPerRow;
int bytesPixel = ImgInfo.BytesPixel;
for (j = 1 - bytesPixel, i = 1; i <= bytesPerRow; i++, j++)
{
rowbfilter[i] = (byte)(
rowb[i] - PngHelperInternal.FilterPaethPredictor(
a: j > 0 ? rowb[j] : (byte)0,
b: rowbprev[i],
c: j > 0 ? rowbprev[j] : (byte)0
)
);
}
}