/// <summary>
/// Crops the <see cref="Image"/> using rectangle calculated by <see cref="Image.BlackArea"/> method.
/// </summary>
/// <param name="dx">The amount by which to expand or shrink the left and right sides of the image black area.</param>
/// <param name="dy">The amount by which to expand or shrink the top and bottom sides of the image black area.</param>
/// <returns>
/// A new cropped <see cref="Image"/>.
/// </returns>
/// <exception cref="NotSupportedException">
/// <para>
/// The <see cref="Image{T}.BitsPerPixel"/> is not 1.
/// </para>
/// </exception>
public Image CropBlackArea(int dx, int dy)
{
// determine black area of the image
Rectangle blackArea = this.BlackArea();
if (dx == 0 && dy == 0)
{
// no frame - simply crop the black area
return(this.Crop(blackArea));
}
// expand target area
Rectangle bounds = Rectangle.Inflate(blackArea, dx, dy);
Image dst = new Image(bounds.Size, this);
if (!blackArea.IsEmpty)
{
Rectangle srcarea = Rectangle.Intersect(bounds, blackArea);
Rectangle dstarea = Rectangle.Offset(srcarea, -bounds.X, -bounds.Y);
Image.CopyArea(dst, dstarea.X, dstarea.Y, srcarea.Width, srcarea.Height, this, srcarea.X, srcarea.Y);
if (this.BitsPerPixel > 1)
{
// set frame to white
dst.SetWhiteBorder(dstarea);
}
}
else
{
if (this.BitsPerPixel > 1)
{
// set all image to white
Vectors.Set(dst.Bits.Length, ulong.MaxValue, dst.Bits, 0);
}
}
dst.AppendTransform(new MatrixTransform(-bounds.X, -bounds.Y));
return(dst);
}
