protected abstract Rectangle GetBoundingBox(Image <TPixel> image, Rectangle rectangle, IBorderAnalysis borderAnalysis, int colorThreshold);
protected override Rectangle GetBoundingBox(Image <Rgb24> image, Rectangle rectangle, IBorderAnalysis borderAnalysis, int colorThreshold)
{
var w = rectangle.Right;
var h = rectangle.Bottom;
var backgroundColor = borderAnalysis.Background.ToPixel <Rgb24>();
// Calculated x-min
var xn = w;
// Calculated x-max
var xm = rectangle.X;
// Calculated y-min
var yn = h;
// Calculated y-max
var ym = rectangle.Y;
for (var y = rectangle.Y; y < h; y++)
{
var row = image.GetPixelRowSpan(y);
for (var x = rectangle.X; x < w; x++)
{
// Current pixel
var c = row[x];
// Delta color values
var bd = Math.Abs(c.B - backgroundColor.B);
var gd = Math.Abs(c.G - backgroundColor.G);
var rd = Math.Abs(c.R - backgroundColor.R);
// Grayscale operation on color delta
// This is done to properly evaluate if
// the perceptual differences are above threshold
if (0.299 * rd + 0.587 * gd + 0.114 * bd <= colorThreshold)
{
continue;
}
if (x < xn)
{
xn = x;
}
if (x > xm)
{
xm = x;
}
if (y < yn)
{
yn = y;
}
if (y > ym)
{
ym = y;
}
}
}
return(new Rectangle(xn, yn, xm - xn + 1, ym - yn + 1));
}
protected override Rectangle GetBoundingBox(Image <Rgba32> image, Rectangle rectangle, IBorderAnalysis borderAnalysis, int colorThreshold)
{
var h = rectangle.Bottom;
var w = rectangle.Right;
var backgroundColor = borderAnalysis.Background.ToPixel <Rgba32>();
var xn = w;
var xm = rectangle.X;
var yn = h;
var ym = rectangle.Y;
for (var y = rectangle.Y; y < h; y++)
{
var row = image.GetPixelRowSpan(y);
for (var x = rectangle.X; x < w; x++)
{
var c = row[x];
var ac = Math.Max(c.A * 0.003921568627451, 1);
var bd = Math.Abs(c.B - backgroundColor.B) * ac;
var gd = Math.Abs(c.G - backgroundColor.G) * ac;
var rd = Math.Abs(c.R - backgroundColor.R) * ac;
if (0.299 * rd + 0.587 * gd + 0.114 * bd <= colorThreshold)
{
var ad = Math.Abs(c.A - backgroundColor.A);
if (ad < colorThreshold)
{
continue;
}
}
if (x < xn)
{
xn = x;
}
if (x > xm)
{
xm = x;
}
if (y < yn)
{
yn = y;
}
if (y > ym)
{
ym = y;
}
}
}
return(new Rectangle(xn, yn, xm - xn + 1, ym - yn + 1));
}
