/// <summary>
/// Finds the bounding rectangle based on the first instance of any color component other
/// than the given one.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="bitmap">The <see cref="Image{TPixel}"/> to search within.</param>
/// <param name="componentValue">The color component value to remove.</param>
/// <param name="channel">The <see cref="RgbaComponent"/> channel to test against.</param>
/// <returns>
/// The <see cref="Rectangle"/>.
/// </returns>
public static Rectangle GetFilteredBoundingRectangle <TPixel>(ImageFrame <TPixel> bitmap, float componentValue, RgbaComponent channel = RgbaComponent.B)
where TPixel : struct, IPixel <TPixel>
{
int width = bitmap.Width;
int height = bitmap.Height;
Point topLeft = default;
Point bottomRight = default;
Func <ImageFrame <TPixel>, int, int, float, bool> delegateFunc;
// Determine which channel to check against
switch (channel)
{
case RgbaComponent.R:
delegateFunc = (pixels, x, y, b) => MathF.Abs(pixels[x, y].ToVector4().X - b) > Constants.Epsilon;
break;
case RgbaComponent.G:
delegateFunc = (pixels, x, y, b) => MathF.Abs(pixels[x, y].ToVector4().Y - b) > Constants.Epsilon;
break;
case RgbaComponent.B:
delegateFunc = (pixels, x, y, b) => MathF.Abs(pixels[x, y].ToVector4().Z - b) > Constants.Epsilon;
break;
default:
delegateFunc = (pixels, x, y, b) => MathF.Abs(pixels[x, y].ToVector4().W - b) > Constants.Epsilon;
break;
}
int GetMinY(ImageFrame <TPixel> pixels)
{
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
if (delegateFunc(pixels, x, y, componentValue))
{
return(y);
}
}
}
return(0);
}
int GetMaxY(ImageFrame <TPixel> pixels)
{
for (int y = height - 1; y > -1; y--)
{
for (int x = 0; x < width; x++)
{
if (delegateFunc(pixels, x, y, componentValue))
{
return(y);
}
}
}
return(height);
}
int GetMinX(ImageFrame <TPixel> pixels)
{
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
if (delegateFunc(pixels, x, y, componentValue))
{
return(x);
}
}
}
return(0);
}
int GetMaxX(ImageFrame <TPixel> pixels)
{
for (int x = width - 1; x > -1; x--)
{
for (int y = 0; y < height; y++)
{
if (delegateFunc(pixels, x, y, componentValue))
{
return(x);
}
}
}
return(height);
}
topLeft.Y = GetMinY(bitmap);
topLeft.X = GetMinX(bitmap);
bottomRight.Y = (GetMaxY(bitmap) + 1).Clamp(0, height);
bottomRight.X = (GetMaxX(bitmap) + 1).Clamp(0, width);
return(GetBoundingRectangle(topLeft, bottomRight));
}
