/// <summary>
/// Apply convolution to given image
/// </summary>
/// <param name="invert">Whether to invert the resulting convolution</param>
/// <param name="intensity">Value by which to multiply inversion strength</param>
internal Bitmap ApplyTo(Bitmap imageSource, bool invert, float intensity)
{
ColorMatrix source = new ColorMatrix(imageSource);
ColorMatrix target = ColorMatrix.Blank(source.Width, source.Height);
float a, r, g, b;
float factor = 0.0f;
int offsetX, offsetY;
int sourceY, sourceX, matrixY, matrixX;
int width = source.Width, height = source.Height;
int startX = 0, startY = 0;
if (!_includeEdges)
{
height -= _radius; width -= _radius; startX = startY = _radius;
}
for (sourceY = startY; sourceY < height; sourceY++)
{
for (sourceX = startX; sourceX < width; sourceX++)
{
a = r = g = b = 0.0f;
if (!(_preserveTransparency && source.IsTransparent(sourceX, sourceY)))
{
// do not convolve alpha channel
a = source.Color[sourceX, sourceY, ColorMatrix.Channel.Alpha];
for (matrixY = -_radius; matrixY <= _radius; matrixY++)
{
// now analyze pixels under matrix
offsetY = Idaho.Utility.Constrain(sourceY + matrixY, 0, height - 1);
for (matrixX = -_radius; matrixX <= _radius; matrixX++)
{
factor = _matrix[matrixY + _radius, matrixX + _radius];
offsetX = Idaho.Utility.Constrain(sourceX + matrixX, 0, width - 1);
// track sum of all color values separately in area
// covered by matrix
r += factor * source.Color[offsetX, offsetY, ColorMatrix.Channel.Red];
g += factor * source.Color[offsetX, offsetY, ColorMatrix.Channel.Green];
b += factor * source.Color[offsetX, offsetY, ColorMatrix.Channel.Blue];
}
}
r /= _total; g /= _total; b /= _total;
}
// apply convolved color to single pixel under consideration
target.SetPixel(sourceX, sourceY, a, r, g, b);
}
}
if (invert)
{
source.CombineWith(target, new ColorMatrix.CombineDelegate(Invert), intensity);
return(source.ToBitmap());
}
else
{
return(target.ToBitmap());
}
}
