[Gdal-dev] some problems in rasterio

[Fu Chen]

I am reading the code of rasterio.cpp. In the code of IRasterIO, 

    for( iBufYOff = 0; iBufYOff < nBufYSize; iBufYOff++ )
    {
        int     iBufOffset, iSrcOffset;
        
        dfSrcY = (iBufYOff+0.5) * dfSrcYInc + nYOff;
        iSrcY = (int) dfSrcY;

        iBufOffset = iBufYOff * nLineSpace;

The problem is why there is a 0.5 here. Isn't iBufYOff=0  --> nYOff?

Sometimes i think the IRasterIO should turn its XOff YOff XSize YSize into double, which will make it more accurate when you are doing supersample and extract data by tiles. 

Best regards

Fu CHEN