protected override unsafe void ProcessFilter( UnmanagedImage image, Rectangle rect )
{
int pixelSize = Image.GetPixelFormatSize( image.PixelFormat ) / 8;
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;
RGB rgb = new RGB( );
HSL hsl = new HSL( );
float kl = 0, bl = 0;
float ks = 0, bs = 0;
// luminance line parameters
if ( inLuminance.Max != inLuminance.Min )
{
kl = ( outLuminance.Max - outLuminance.Min ) / ( inLuminance.Max - inLuminance.Min );
bl = outLuminance.Min - kl * inLuminance.Min;
}
// saturation line parameters
if ( inSaturation.Max != inSaturation.Min )
{
ks = ( outSaturation.Max - outSaturation.Min ) / ( inSaturation.Max - inSaturation.Min );
bs = outSaturation.Min - ks * inSaturation.Min;
}
// 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 )
{
rgb.Red = ptr[RGB.R];
rgb.Green = ptr[RGB.G];
rgb.Blue = ptr[RGB.B];
// convert to HSL
AForge.Imaging.HSL.FromRGB( rgb, hsl );
// do luminance correction
if ( hsl.Luminance >= inLuminance.Max )
hsl.Luminance = outLuminance.Max;
else if ( hsl.Luminance <= inLuminance.Min )
hsl.Luminance = outLuminance.Min;
else
hsl.Luminance = kl * hsl.Luminance + bl;
// do saturation correct correction
if ( hsl.Saturation >= inSaturation.Max )
hsl.Saturation = outSaturation.Max;
else if ( hsl.Saturation <= inSaturation.Min )
hsl.Saturation = outSaturation.Min;
else
hsl.Saturation = ks * hsl.Saturation + bs;
// convert back to RGB
AForge.Imaging.HSL.ToRGB( hsl, rgb );
ptr[RGB.R] = rgb.Red;
ptr[RGB.G] = rgb.Green;
ptr[RGB.B] = rgb.Blue;
}
ptr += offset;
}
}
}