// Applies simple sharpening to the row data to improve performance of the 1D Readers.
public override BitArray getBlackRow(int y, BitArray row)
{
LuminanceSource source = LuminanceSource;
int width = source.Width;
if (row == null || row.Size < width)
{
row = new BitArray(width);
}
else
{
row.clear();
}
initArrays(width);
sbyte[] localLuminances = source.getRow(y, luminances);
int[] localBuckets = buckets;
for (int x = 0; x < width; x++)
{
int pixel = localLuminances[x] & 0xff;
localBuckets[pixel >> LUMINANCE_SHIFT]++;
}
int blackPoint = estimateBlackPoint(localBuckets);
int left = localLuminances[0] & 0xff;
int center = localLuminances[1] & 0xff;
for (int x = 1; x < width - 1; x++)
{
int right = localLuminances[x + 1] & 0xff;
// A simple -1 4 -1 box filter with a weight of 2.
int luminance = ((center << 2) - left - right) >> 1;
if (luminance < blackPoint)
{
row.set_Renamed(x);
}
left = center;
center = right;
}
return row;
}
/// <summary> A fast method to retrieve one row of data from the matrix as a BitArray.
///
/// </summary>
/// <param name="y">The row to retrieve
/// </param>
/// <param name="row">An optional caller-allocated BitArray, will be allocated if null or too small
/// </param>
/// <returns> The resulting BitArray - this reference should always be used even when passing
/// your own row
/// </returns>
public BitArray getRow(int y, BitArray row)
{
if (row == null || row.Size < width)
{
row = new BitArray(width);
}
int offset = y * rowSize;
for (int x = 0; x < rowSize; x++)
{
row.setBulk(x << 5, bits[offset + x]);
}
return row;
}
