VirtualPixelMethod enum 
Enum of supported virtual pixel methods.
enum VirtualPixelMethod {
  BACKGROUND = 1,
  EDGE = 3,
  MIRROR = 4,
  RANDOM = 5,
  TILE = 6,
  TRANSPARENT = 7,
  BLACK = 9,
  GRAY = 10,
  WHITE = 11,
  HORIZONTAL_TILE = 12,
  VERTICAL_TILE = 13,
  HORIZONTAL_TILE_EDGE = 14,
  VERTICAL_TILE_EDGE = 15,
}Virtual pixels are pixels that are out of actual image bounds. There are different methods that can be used to get color of such pixels.
TIP
See virtual pixel methods behavior examples at ImageMagick docs.
Method descriptions 
BACKGROUND 
Uses image background color.
EDGE 
Uses color of closest image edge pixel.
MIRROR 
Behaves like if image is infinite pattern, and each next tile of that pattern is mirrored version of sibling tile.
RANDOM 
Uses random color from image color palette.
TILE 
Behaves like if image is infinite pattern.
TRANSPARENT 
Uses transparent color.
BLACK 
Uses black color.
GRAY 
Uses gray color.
WHITE 
Uses white color.
HORIZONTAL_TILE 
Behaves like image is infinitely tiled pattern across horizontal axis and uses background color for vertical axis.
VERTICAL_TILE 
Behaves like image is infinitely tiled pattern across vertical axis and uses background color for horizontal axis.
HORIZONTAL_TILE_EDGE 
Behaves like image is infinitely tiled pattern across horizontal axis and uses closest edge pixel color across vertical axis.
VERTICAL_TILE_EDGE 
Behaves like image is infinitely tiled pattern across vertical axis and uses closest edge pixel color across horizontal axis.
