/// <summary>
/// Create an SHA1 hash from the image data (pixels only) to allow us to find
/// duplicate images. Note that this ignores EXIF metadata, so the hash will
/// find duplicate images even if the metadata is different.
/// </summary>
/// <param name="source"></param>
/// <returns>String hash of the image data</returns>
public static string GetHash(SKBitmap sourceBitmap)
{
string result = null;
try
{
var hashWatch = new Stopwatch("HashImage");
var pixels = sourceBitmap.GetPixelSpan();
var hash = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
for (int row = 0; row < sourceBitmap.Height; row++)
{
var rowPixels = pixels.Slice(row * sourceBitmap.RowBytes, sourceBitmap.RowBytes);
byte[] rgbaBytes = MemoryMarshal.AsBytes(rowPixels).ToArray();
hash.AppendData(rgbaBytes);
}
result = hash.GetHashAndReset().ToHex(true);
hashWatch.Stop();
Logging.LogVerbose($"Hashed image ({result}) in {hashWatch.HumanElapsedTime}");
}
catch (Exception ex)
{
Logging.LogError($"Exception while calculating hash: {ex.Message}");
}
return(result);
}
private void InvertDraw(SKBitmap skBitmap, SKBitmap skBitmapInvert)
{
// Fast local copy
var originalBytes = skBitmap.GetPixelSpan();
var invertBytes = skBitmapInvert.GetPixelSpan();
int total = originalBytes.Length / 4;
for (int i = 0; i < total; i++)
{
// RGBA8888
int alphaByte = (i << 2) + 3;
if (invertBytes[alphaByte] == 0)
{
continue;
}
// Set color
var targetColor = SKColors.White;
if (originalBytes[alphaByte - 1] == 255)
{
targetColor = SKColors.Black;
}
int x, y;
y = Math.DivRem(i, skBitmapInvert.Width, out x);
skBitmap.SetPixel(x, y, targetColor);
}
}
private static void CompareToSkiaResultsImpl(TestImageProvider <Rgba32> provider, IPath shape)
{
using Image <Rgba32> image = provider.GetImage();
image.Mutate(c => c.Fill(Color.White, shape));
image.DebugSave(provider, "ImageSharp", appendPixelTypeToFileName: false, appendSourceFileOrDescription: false);
using var bitmap = new SKBitmap(new SKImageInfo(image.Width, image.Height));
using var skPath = new SKPath();
foreach (ISimplePath loop in shape.Flatten())
{
ReadOnlySpan <SKPoint> points = MemoryMarshal.Cast <PointF, SKPoint>(loop.Points.Span);
skPath.AddPoly(points.ToArray());
}
using var paint = new SKPaint
{
Style = SKPaintStyle.Fill,
Color = SKColors.White,
IsAntialias = true,
};
using var canvas = new SKCanvas(bitmap);
canvas.Clear(new SKColor(0, 0, 0));
canvas.DrawPath(skPath, paint);
using var skResultImage =
Image.LoadPixelData <Rgba32>(bitmap.GetPixelSpan(), image.Width, image.Height);
skResultImage.DebugSave(
provider,
"SkiaSharp",
appendPixelTypeToFileName: false,
appendSourceFileOrDescription: false);
ImageSimilarityReport <Rgba32, Rgba32> result = ImageComparer.Exact.CompareImagesOrFrames(image, skResultImage);
throw new Exception(result.DifferencePercentageString);
}
private static byte[] BitmapToBytes(SKBitmap bmp) => bmp.GetPixelSpan().ToArray();
internal static string EncodeInternal(int xComponent, int yComponent, SKBitmap bitmap) => CoreBlurHashEncoder.Encode(xComponent, yComponent, bitmap.Width, bitmap.Height, bitmap.GetPixelSpan(), bitmap.RowBytes, PixelFormat.RGB888x);
