After upgrading to stretch the preview window is empty/unusable:
i.e. it seems bug 712281 should be reopened.

How to reproduce:

(no .sane/xsane yet)
start xsane
close the preview window
(at this point the preview window can still be reopened ok)
stop xsane
start xsane
open the preview

Result: an empty window, no buttons, and moving the mouse
generates strips of mostly black blobs on the top and left of
the window.

But -- quitting xsane now, and restarting it does result
in a working preview window again! So the problem seems to be
some missing initialization of the preview window when
starting without one.

As described in bug 712281,  rm -r ~/.sane/xsane also resolves
the problem, temporarily at least, but that is because
without .sane/xsane the default is to start _with_ the
preview window.

The work around as described in the Ubuntu version works ok for me.

https://bugs.launchpad.net/ubuntu/+source/xsane/+bug/1410756

Opening the preview page with the Ctrl-1 and then shutting down and
restarting it starts with the preview pane with all the buttons
displayed
and working properly. - Thank God for this work around - really
annoying otherwise.

Andrew

I can confirm the bug still exists in debian buster.
(the workaround deleting .sane/xsane works too.)

I am on Arch Linux but affected by the very same issue. There is another
workaround that worked for me:
running with --sync (i. e. xsane --sync)

Looks like the preview window gets created on each startup and then later -
corresponding to settings -
either it's left as is or hidden. Maybe if it's happening too fast (w/o
sync) this leads to corruption.

Quick and dirty semi-solution (certainly not ideal but al least working
100%) is to discard the hiding part (that is:
ignore the setting at startup):

--- xsane.c.orig 2020-09-23 12:14:13.366814683 +0200
+++ xsane.c 2020-09-23 12:14:17.106792054 +0200
@@ -5347,10 +5347,10 @@
   {
     gtk_widget_show(xsane.preview->top);
   }
-  else
-  {
-    gtk_widget_hide(xsane.preview->top);
-  }
+  //else
+  //{
+    //gtk_widget_hide(xsane.preview->top);
+  //}

 gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(xsane.show_preview_widget),
xsane.show_preview);

   xsane_define_maximum_output_size(); /* draw maximum output frame in
preview window if necessary */

I do hope someone knowledgeable steps in and prepare a proper fix.

BR, jose

I do not see what I am scanning. Hence I cannot adjust brightness,
contrast, dimensions. And as my last working xsane scan was not a full
page, I now stuck with those dimension. Don't tell me I could change
the dimensions in a submenue, I know.

Scanning blindly makes xsane unusuable!

BTW, as maybe it's related: I have enabled "preview" in the window (de:
Ansicht) pull-down menue. And then stored the settings. Nonetheless the
(empty) preview window does not get opened on start of xsane.

Hi

After some more research it seams this bug could be somehow DE related:

I normaly work in a fluxbox environment. And so I did today when I hit
this bug (not for the first time!). As I was in a hurry with some
documents I had to scan, I installed an other scanning application
(simple scan) which did the job.

On the same HW and same installation I later switched to a different
WM/DE: lxqt

When I started xsane while running lxqt, the preview window opened for a
fraction of a second, but closed instantly. I could reopen it and it
worked as it should. Even after closing and reopening xsane, the
preview window opened and stayed open from now on. It even worked after
a reboot. And, to my surprise, it now works in fluxbox, too. As if
there never was a bug.

Bug closed? NO!

This malfunction occurred over the last two years again and again 9 out
of 10 times I wanted to use xsane. And it is not clear why it happens
and when it will happen again.