Calculates the dimensions of suitable rectangles for use with with-page-transform.

The ```
get-page-area
```

function is provided to simplify the calculation of suitable rectangles for use with with-page-transform. It calculates and returns the width and height of the rectangle in the user's coordinate space that corresponds to one printable page, based on the logical resolution of the user's coordinate space in dpi.

For example, if a logical resolution of 72 dpi was specified, this means that each unit in user space would map onto 1/72 of an inch on the printed page, assuming that no *
scale*
is specified.

If *
dpi*
is ```
nil
```

or unspecified, the logical resolution of the specified screen is used, or the logical resolution of the default screen if no screen is specified. The *
dpi*
argument can be a number, or a list of two elements representing the logical resolution of the coordinate spaces in the x and y directions respectively.

If *
scale*
is specified the rectangle is calculated so that the image is scaled by this factor when printed. It defaults to 1.0.

*CAPI Reference Manual - 15 Dec 2011*