"Return pixel size in micrometers."
(let ((pixel-dim (pixel-dimensions format-spec))
(imager-dim (imager-dimensions format-spec)))
- (values (* 1000 (/ (car imager-dim) (car pixel-dim)))
- (* 1000 (/ (cdr imager-dim) (cdr pixel-dim))))))
+ (when (and pixel-dim imager-dim)
+ (values (* 1000 (/ (car imager-dim) (car pixel-dim)))
+ (* 1000 (/ (cdr imager-dim) (cdr pixel-dim)))))))
+
(defun output-dimensions (format-spec)
"Returns the output dimensions in mm of a FORMAT."
(getf (find-format format-spec) :output))