/// <summary>
/// Traces the edges of a given <see cref="Image"/>.
/// TODO: Move this to another class.
/// </summary>
/// <param name="source">
/// The source <see cref="Image"/>.
/// </param>
/// <param name="destination">
/// The destination <see cref="Image"/>.
/// </param>
/// <param name="threshold">
/// The threshold (between 0 and 255).
/// </param>
/// <returns>
/// The a new instance of <see cref="Bitmap"/> traced.
/// </returns>
private static Bitmap Trace(Image source, Image destination, byte threshold = 0)
{
int width = source.Width;
int height = source.Height;
// Grab the edges converting to greyscale, and invert the colors.
ConvolutionFilter filter = new ConvolutionFilter(new SobelEdgeFilter(), true);
using (Bitmap temp = filter.Process2DFilter(source))
{
destination = new InvertMatrixFilter().TransformImage(temp, destination);
// Darken it slightly to aid detection
destination = Adjustments.Brightness(destination, -5);
}
// Loop through and replace any colors more white than the threshold
// with a transparent one.
using (FastBitmap destinationBitmap = new FastBitmap(destination))
{
Parallel.For(
0,
height,
y =>
{
for (int x = 0; x < width; x++)
{
// ReSharper disable AccessToDisposedClosure
Color color = destinationBitmap.GetPixel(x, y);
if (color.B >= threshold)
{
destinationBitmap.SetPixel(x, y, Color.Transparent);
}
// ReSharper restore AccessToDisposedClosure
}
});
}
// Darken it again to average out the color.
destination = Adjustments.Brightness(destination, -5);
return((Bitmap)destination);
}
/// <summary>
/// Traces the edges of a given <see cref="Image"/>.
/// </summary>
/// <param name="source">
/// The source <see cref="Image"/>.
/// </param>
/// <param name="destination">
/// The destination <see cref="Image"/>.
/// </param>
/// <param name="threshold">
/// The threshold (between 0 and 255).
/// </param>
/// <returns>
/// The a new instance of <see cref="Bitmap"/> traced.
/// </returns>
public static Bitmap Trace(Image source, Image destination, byte threshold = 0)
{
int width = source.Width;
int height = source.Height;
// Grab the edges converting to greyscale, and invert the colors.
ConvolutionFilter filter = new ConvolutionFilter(new SobelEdgeFilter(), true);
using (Bitmap temp = filter.Process2DFilter(source))
{
destination = new InvertMatrixFilter().TransformImage(temp, destination);
// Darken it slightly to aid detection
destination = Adjustments.Brightness(destination, -5);
}
// Loop through and replace any colors more white than the threshold
// with a transparent one.
using (FastBitmap destinationBitmap = new FastBitmap(destination))
{
Parallel.For(
0,
height,
y =>
{
for (int x = 0; x < width; x++)
{
// ReSharper disable AccessToDisposedClosure
Color color = destinationBitmap.GetPixel(x, y);
if (color.B >= threshold)
{
destinationBitmap.SetPixel(x, y, Color.Transparent);
}
// ReSharper restore AccessToDisposedClosure
}
});
}
// Darken it again to average out the color.
destination = Adjustments.Brightness(destination, -5);
return (Bitmap)destination;
}
