public static Vector <double> BitmapToVector(Stream stream, BitmapChannel channel = BitmapChannel.Gray)
{
using var bitmap = Bitmap.FromStream(stream);
return(BitmapToVector(bitmap as Bitmap, channel));
}
public unsafe static Vector <double> BitmapToVector(Bitmap bitmap, BitmapChannel channel = BitmapChannel.Gray)
{
int width = bitmap.Width;
int height = bitmap.Height;
int pixelCount = width * height;
bool needDispose = false;
bool isGray = false;
var rect = new Rectangle(0, 0, width, height);
int depth = Bitmap.GetPixelFormatSize(bitmap.PixelFormat);
switch (bitmap.PixelFormat)
{
case PixelFormat.Format24bppRgb:
case PixelFormat.Format32bppArgb:
case PixelFormat.Format32bppPArgb:
case PixelFormat.Format32bppRgb:
break;
default:
bitmap = channel == BitmapChannel.Gray ? MakeGrayscale(bitmap) : MakeColor(bitmap);
needDispose = true;
break;
}
if (!needDispose && channel == BitmapChannel.Gray)
{
bitmap = MakeGrayscale(bitmap);
needDispose = true;
isGray = true;
}
var result = new double[pixelCount];
var bitmapData = bitmap.LockBits(rect, ImageLockMode.ReadOnly, bitmap.PixelFormat);
try
{
unsafe
{
byte *scan0 = (byte *)bitmapData.Scan0.ToPointer();
var ptr = bitmapData.Scan0;
int startIndex;
switch (depth)
{
case 8: // For 8 bpp get color value (Red, Green and Blue values are the same)
if (channel == BitmapChannel.Alpha)
{
break;
}
for (int y = 0; y < bitmapData.Height; y++)
{
var rowB = (byte *)bitmapData.Scan0 + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int x = 0; x < bitmapData.Width; x++)
{
result[startIndex + x] = rowB[x];
}
}
PointwiseDivideInPlace(result, 256.0);
break;
case 16: // For 16 bpp - gray with 65536 shades
if (channel == BitmapChannel.Alpha)
{
break;
}
for (int y = 0; y < bitmapData.Height; y++)
{
var rowS = (short *)bitmapData.Scan0 + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int x = 0; x < bitmapData.Width; x++)
{
result[startIndex + x] = rowS[x];
}
}
PointwiseDivideInPlace(result, 65536.0);
break;
case 24: // For 24 bpp get Red, Green and Blue
case 32: // For 32 bpp get Red, Green, Blue and Alpha
if (channel == BitmapChannel.Alpha && depth == 24)
{
break;
}
int step = depth / 8;
if (channel == BitmapChannel.Gray)
{
if (isGray && UseGrayConverter)
{
for (int y = 0; y < bitmapData.Height; y++)
{
var row3B = (byte *)bitmapData.Scan0.ToPointer() + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
result[startIndex + i] = row3B[x]; //In gray image (made with method MakeGray()) R = G = B.
}
}
PointwiseDivideInPlace(result, 256.0);
}
else if (UseAvx)
{
var vectorGrayCoeffAvx = Vector256.Create(0.11d, 0.59d, 0.3d, 0d);
for (int y = 0; y < bitmapData.Height; y++)
{
var row3B = (byte *)bitmapData.Scan0 + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
var vectorB = Vector128.Create((int)row3B[x], (int)row3B[x + 1], (int)row3B[x + 2], (int)0);
var vectorD = Avx.ConvertToVector256Double(vectorB);
var vectorGray = Avx.Multiply(vectorD, vectorGrayCoeffAvx);
double dGray = vectorGray.GetElement(0) + vectorGray.GetElement(1) + vectorGray.GetElement(2);
result[startIndex + i] = dGray;
}
}
PointwiseDivideInPlace(result, 256.0);
}
else if (UseSIMD)
{
var vectorGrayCoeff = new Numerics.Vector4(0.11f, 0.59f, 0.3f, 0f);
for (int y = 0; y < bitmapData.Height; y++)
{
var row3B = (byte *)bitmapData.Scan0 + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
var vectorF = new Numerics.Vector4(row3B[x], row3B[x + 1], row3B[x + 2], 0);
var fGray = Numerics.Vector4.Dot(vectorF, vectorGrayCoeff);
result[startIndex + i] = fGray;
}
}
PointwiseDivideInPlace(result, 256.0);
}
else
{
for (int y = 0; y < bitmapData.Height; y++)
{
var row3B = (byte *)bitmapData.Scan0.ToPointer() + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
double gray = 0.11d * row3B[x] + 0.59d * row3B[x + 1] + 0.11d * row3B[x + 2];
result[startIndex + i] = gray;
}
}
PointwiseDivideInPlace(result, 256.0);
}
}
else
{
for (int y = 0; y < bitmapData.Height; y++)
{
var row3B = (byte *)bitmapData.Scan0 + (y * bitmapData.Stride);
startIndex = y * bitmapData.Width;
if (bitmapData.Stride < 0)
{
startIndex = (pixelCount - bitmapData.Width) - startIndex;
}
switch (channel)
{
case BitmapChannel.Red:
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
result[startIndex + i] = row3B[x + 2];
}
break;
case BitmapChannel.Green:
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
result[startIndex + i] = row3B[x + 1];
}
break;
case BitmapChannel.Blue:
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
result[startIndex + i] = row3B[x];
}
break;
case BitmapChannel.Alpha:
if (depth == 32)
{
for (int i = 0, x = 0; i < bitmapData.Width; i++, x += step)
{
result[startIndex + i] = row3B[x + 3];
}
}
else
{
//Do nothing, 24bit images have no alpha channel
}
break;
}
}
PointwiseDivideInPlace(result, 256.0);
}
break;
}
}
}
finally
{
bitmap.UnlockBits(bitmapData);
if (needDispose)
{
bitmap.Dispose();
}
}
return(Vector <double> .Build.Dense(result));
}
public static Vector <double> BitmapToVector(string fileName, BitmapChannel channel = BitmapChannel.Gray)
{
using var bitmap = Bitmap.FromFile(fileName);
return(BitmapToVector(bitmap as Bitmap, channel));
}
