/// <summary>
/// Calculates a 64 bit difference hash.
/// </summary>
/// <param name="stream">
/// The image stream to hash.
/// </param>
/// <returns>
/// A 64 bit difference hash.
/// </returns>
public static long HashLong(Stream stream)
{
const int Width = 9;
const int Height = 8;
// TODO: allocations
ImagePipeline
.FromStream(stream)
.Resize(new ResizeOptions(Width, Height, Fit.Fill))
.Grayscale()
.Normalize()
.Raw()
.ToBuffer(out var normalized);
var bitArray = new BitArray(64);
var bit = 0;
for (var x = 0; x < Width - 1; x++)
{
for (var y = 0; y < Height; y++)
{
bitArray.Set(bit, normalized[y * Height + x] < normalized[y * Height + x + 1]);
bit++;
}
}
var array = new byte[8];
bitArray.CopyTo(array, 0);
return(BitConverter.ToInt64(array, 0));
}
/// <summary>
/// Calculates a 16 bit difference hash.
/// </summary>
/// <param name="stream">
/// The image stream to hash.
/// </param>
/// <returns>
/// A 16 bit difference hash.
/// </returns>
public static short HashShort(Stream stream)
{
const int Width = 6;
const int Height = 4;
// TODO: allocations
ImagePipeline
.FromStream(stream)
.Resize(new ResizeOptions {
Canvas = Canvas.IgnoreAspectRatio,
Height = Height,
Width = Width,
})
.Grayscale()
.Normalize()
.Raw()
.ToBuffer(out var normalized);
var bitArray = new BitArray(16);
var bit = 0;
for (var x = 0; x < Width - 1; x++)
{
for (var y = 0; y < Height; y++)
{
if (IsCorner(x, y, Width, Height))
{
// skip corners
continue;
}
bitArray.Set(bit, normalized[y * Height + x] < normalized[y * Height + x + 1]);
bit++;
}
}
var array = new byte[2];
bitArray.CopyTo(array, 0);
return(BitConverter.ToInt16(array, 0));
}
public static void returns_pipeline()
{
using var stream = File.OpenRead(TestValues.InputPath);
ImagePipeline.FromStream(stream).ShouldNotBeNull();
}
