diff --git a/cpdf.ml b/cpdf.ml
index ff7a9f4..7d82719 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -2554,7 +2554,7 @@ let hard_box pdf range boxname mediabox_if_missing fast =
                  then Pdf.parse_rectangle page.Pdfpage.mediabox
                  else error "hard_box: Box not found"
        in
-         let ops = [Pdfops.Op_re (minx, miny, maxx, maxy); Pdfops.Op_W; Pdfops.Op_n] in
+         let ops = [Pdfops.Op_re (minx, miny, maxx -. minx, maxy -. miny); Pdfops.Op_W; Pdfops.Op_n] in
            Pdfpage.prepend_operators pdf ops ~fast:fast page)
     pdf
     range
diff --git a/cpdfmanual.tex b/cpdfmanual.tex
index af14013..095a491 100644
--- a/cpdfmanual.tex
+++ b/cpdfmanual.tex
@@ -1,3 +1,4 @@
+%FIXME: Document new -hard-box option
 %FIXME: Document that -upright also shifts the page to 0,0
 \documentclass{book}
 \usepackage{palatino}