protected override unsafe void ProcessFilter( UnmanagedImage image, Rectangle rect )
{
// get pixel size
int pixelSize = ( image.PixelFormat == PixelFormat.Format24bppRgb ) ? 3 : 4;
int startX = rect.Left;
int startY = rect.Top;
int stopX = startX + rect.Width;
int stopY = startY + rect.Height;
int offset = image.Stride - rect.Width * pixelSize;
int radius2 = radius * radius;
int dr, dg, db;
// sphere's center
int cR = center.Red;
int cG = center.Green;
int cB = center.Blue;
// fill color
byte fR = fill.Red;
byte fG = fill.Green;
byte fB = fill.Blue;
// do the job
byte* ptr = (byte*) image.ImageData.ToPointer( );
// allign pointer to the first pixel to process
ptr += ( startY * image.Stride + startX * pixelSize );
// for each row
for ( int y = startY; y < stopY; y++ )
{
// for each pixel
for ( int x = startX; x < stopX; x++, ptr += pixelSize )
{
dr = cR - ptr[RGB.R];
dg = cG - ptr[RGB.G];
db = cB - ptr[RGB.B];
// calculate the distance
if ( dr * dr + dg * dg + db * db <= radius2 )
{
// inside sphere
if ( !fillOutside )
{
ptr[RGB.R] = fR;
ptr[RGB.G] = fG;
ptr[RGB.B] = fB;
}
}
else
{
// outside sphere
if ( fillOutside )
{
ptr[RGB.R] = fR;
ptr[RGB.G] = fG;
ptr[RGB.B] = fB;
}
}
}
ptr += offset;
}
}
}