Return the \(x\) and \(y\) coordinates of each pixel in a pixel image or binary mask.

```
raster.x(w, drop=FALSE)
raster.y(w, drop=FALSE)
raster.xy(w, drop=FALSE)
```

w

A pixel image (object of class `"im"`

) or a
mask window (object of class `"owin"`

of type `"mask"`

).

drop

Logical.
If `TRUE`

, then coordinates of pixels that lie outside the
window are removed.
If `FALSE`

(the default) then the coordinates of every
pixel in the containing rectangle are retained.

`raster.xy`

returns a list with components `x`

and `y`

which are numeric vectors of equal length containing the pixel coordinates.

If `drop=FALSE`

,
`raster.x`

and `raster.y`

return
a matrix of the same dimensions as the pixel grid in `w`

,
and giving the value of the \(x\) (or \(y\)) coordinate
of each pixel in the raster.

If `drop=TRUE`

,
`raster.x`

and `raster.y`

return numeric vectors.

The argument `w`

should be either
a pixel image (object of class `"im"`

)
or a mask window (an object of class
`"owin"`

of type `"mask"`

).

If `drop=FALSE`

(the default), the
functions `raster.x`

and `raster.y`

return
a matrix of the same dimensions as the
pixel image or mask itself, with entries giving the \(x\) coordinate
(for `raster.x`

) or \(y\) coordinate (for `raster.y`

)
of each pixel in the pixel grid.

If `drop=TRUE`

, pixels that lie outside the
window `w`

(or outside the domain of the image `w`

)
are removed, and `raster.x`

and `raster.y`

return numeric vectors containing the coordinates of the
pixels that are inside the window `w`

.

The function `raster.xy`

returns a list
with components `x`

and `y`

which are numeric vectors of equal length containing the pixel coordinates.

# NOT RUN { u <- owin(c(-1,1),c(-1,1)) # square of side 2 w <- as.mask(u, eps=0.01) # 200 x 200 grid X <- raster.x(w) Y <- raster.y(w) disc <- owin(c(-1,1), c(-1,1), mask=(X^2 + Y^2 <= 1)) # plot(disc) # approximation to the unit disc # }