This function generates a rectangular grid of locations in the plane,
tests whether each of these locations lies inside the
window `w`

, and stores the results as a binary pixel image
or `mask' (an object of class `"owin"`

, see `owin.object`

). The most common use of this function is to approximate the shape
of another window `w`

by a binary pixel image. In this case,
we will usually want to have a very fine grid of pixels.

This function can also be used to generate a coarsely-spaced grid of
locations inside a window, for purposes such as subsampling
and prediction.

The grid spacing and location are controlled by the
arguments `eps`

, `dimyx`

and `xy`

,
which are mutually incompatible.

If `eps`

is given, then the grid spacing will be
approximately `eps`

in both the $x$ and $y$ directions.

If `dimyx`

is given, then the pixel grid will be an
$m \times n$ rectangular grid
where $m, n$ are given by `dimyx[2]`

, `dimyx[1]`

respectively. **Warning:** `dimyx[1]`

is the number of
pixels in the $y$ direction, and `dimyx[2]`

is the number
in the $x$ direction.

If `xy`

is given, then this should be a structure
containing two elements `x`

and `y`

which are the
vectors of $x$ and `y`

coordinates of the margins
of the grid. The pixel coordinates will be generated
from these two vectors. In this case `w`

may be omitted.
If neither `eps`

nor `dimyx`

nor `xy`

is given,
the pixel raster dimensions are obtained from
`spatstat.options("npixel")`

.

There is no inverse of this function!