To obtain the pixel dimensions of an image, load the image using
load-image
and then use the readers
image-width
and
image-height
. The first argument to
load-image
must be a pane in a displayed interface.
To query the dimensions before displaying anything you can create and "display" an interface made with the
:display-state :hidden
initarg. Call
load-image
with this hidden interface and your
external-image
object, and then use the readers
image-width
and
image-height
.