# HG changeset patch
# User Carnë Draug <carandraug@octave.org>
# Date 1404924356 -3600
# Node ID d316de4780cec0a680648740660130b1e2e63ae4
# Parent  1a31fbf8517bba4919c615625df9cacec25274c5
imcrop.m: do not confuse array of zeros as array of handles (bug #42714).

diff --git a/inst/imcrop.m b/inst/imcrop.m
--- a/inst/imcrop.m
+++ b/inst/imcrop.m
@@ -129,7 +129,11 @@
     ## use current figure
     from_fig = true;
     h = gcf ();
-  elseif (fnargin == 1 && ishandle (varargin{1}))
+  ## We check isscalar() because ishandle() accepts arrays of handles, and we
+  ## check "!= 0" because 0 is and handle for the "root figure" which is
+  ## invalid for imcrop (see bug #42714).
+  elseif (fnargin == 1 && isscalar (varargin{1})
+          && varargin{1} != 0 && ishandle (varargin{1}))
     ## use specified figure
     from_fig = true;
     h = varargin{1};
@@ -222,3 +226,7 @@
 %! assert (nthargout (2, @imcrop, a, rect), rect);
 %! assert (nthargout ([3 4], 4, @imcrop, a, rect), {a(30:35, 20:23) rect});
 
+## 0 is the root figure (always true figure handle), so make sure we use
+## scalar 0 as image data, not as figure handle.
+%!assert (imcrop (0, [0.5 0.5 0.9 0.9]), 0);
+%!assert (imcrop (zeros (5), [1 1 1 1]), zeros (2));