public void TestComputeHash()
{
using (var imageStream = TestImage.Flora.GetStream())
using (var bmp = (Bitmap)Image.FromStream(imageStream))
{
var hash = BitmapHash.Compute(bmp);
Assert.NotNull(hash);
}
}
//public float Compare(Hash x, Hash y)
//{
// var hashVariants = new List<byte[]> { x.HashData }; // 0°
// hashVariants.Add(BitmapHash.RotateBitmapHash(hashVariants.Last())); // 90°
// hashVariants.Add(BitmapHash.RotateBitmapHash(hashVariants.Last())); // 180°
// hashVariants.Add(BitmapHash.RotateBitmapHash(hashVariants.Last())); // 270°
// return hashVariants.Select(x => BinaryUtils.ComputeByteArrayEquality(x, y.HashData)).Max();
//}
public HashContext CreateContext(Hash hash)
{
var variants = new ReadOnlyMemory <byte> [4];
variants[0] = hash.HashData.AsMemory(0, 32);
variants[1] = BitmapHash.RotateBitmapHash(variants[0].Span); // 90°
variants[2] = BitmapHash.RotateBitmapHash(variants[1].Span); // 180°
variants[3] = BitmapHash.RotateBitmapHash(variants[2].Span); // 270°
var colorData = hash.HashData.AsMemory(32);
return(new HashContext(colorData, variants));
}
public void TestCompareCompressedPicture()
{
using (var imageStream1 = TestImage.Flora.GetStream())
using (var bmp1 = (Bitmap)Image.FromStream(imageStream1))
using (var imageStream2 = TestImage.FloraCompressed.GetStream())
using (var bmp2 = (Bitmap)Image.FromStream(imageStream2))
{
var hash1 = BitmapHash.Compute(bmp1);
var hash2 = BitmapHash.Compute(bmp2);
var diff = BinaryUtils.ComputeByteArrayEquality(hash1, hash2);
Assert.True(diff > 0.9);
}
}
public void TestRotateBitmapHash()
{
byte[] matrix = new byte[] {
0b00010001, 0b00110001,
0b01100111, 0b01011101,
0b00111010, 0b10001010,
0b01110101, 0b11111101,
0b00011101, 0b01011101,
0b10100100, 0b00110011,
0b01101011, 0b11000100,
0b01110011, 0b10000111,
0b00010100, 0b01100101,
0b11001111, 0b00111110,
0b01100011, 0b10011100,
0b01000110, 0b01100000,
0b00011111, 0b01010110,
0b00010111, 0b11110001,
0b10011001, 0b00101101,
0b00010100, 0b10010010
};
byte[] expectedResult = new byte[]
{
0b01000010, 0b00100000,
0b00001110, 0b11001010,
0b00000100, 0b11101110,
0b11110001, 0b10011101,
0b01010010, 0b01010100,
0b10111011, 0b00111010,
0b00111110, 0b11000110,
0b01110110, 0b11011011,
0b10100100, 0b11001100,
0b00111001, 0b01011010,
0b01101011, 0b00101001,
0b10110110, 0b00111011,
0b01000110, 0b00011110,
0b01010111, 0b11011010,
0b10010010, 0b10100100,
0b01100001, 0b10111011,
};
var result = BitmapHash.RotateBitmapHash(matrix);
Assert.Equal(expectedResult, result);
}
public FileInformation Load(IFile file, Stream stream)
{
_logger.LogDebug("Load file information of {filename}", file.Filename);
PhotoProperties?properties;
Hash fileHash;
DateTimeOffset fileCreatedOn;
fileCreatedOn = GetCreationDate(stream, file);
stream.Position = 0;
try
{
using var bmp = new Bitmap(stream);
var width = bmp.Width;
var height = bmp.Height;
var bmpHash = new Hash(BitmapHash.Compute(bmp));
properties = new PhotoProperties(bmpHash, width, height);
}
catch (Exception)
{
properties = null;
}
stream.Position = 0;
fileHash = _fileHasher.ComputeHash(stream);
var fileInformation = new FileInformation(file.Filename, file.CreatedOn, file.ModifiedOn, fileHash, file.Length,
fileCreatedOn, properties, file.RelativeFilename);
_logger.LogDebug("FileInformation of file {filename} loaded: {@data}", file.Filename, fileInformation);
return(fileInformation);
}
