From eea2c495d93042e1b09a3a0e68b23d389dc0fc4e Mon Sep 17 00:00:00 2001
From: Raman Gupta <rocketraman@gmail.com>
Date: Wed, 19 Apr 2023 12:46:49 -0400
Subject: [PATCH] warn on deskew but no crop

Best practices from the sane mailing list indicate that deskew should
be used in combination with crop for best results. Warn if not doing
so.
---
 scan | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/scan b/scan
index c23dad2..f2246da 100755
--- a/scan
+++ b/scan
@@ -258,6 +258,13 @@ case "$SIZE" in
 
 esac
 
+if [[ $DESKEW == 1 ]]; then
+  if [[ $CROP != 1 ]]; then
+    echo >&2 'Warning: `--deskew` specified, but `--crop` not specified. It is recommended to scan at max height/width and then crop to give deskew the best chance of working correctly.'
+  fi
+  DESKEW="--swdeskew=yes"
+fi
+
 if [[ $CROP != 1 && "$PGHEIGHT" != "" ]]; then
   PGHEIGHTIN=$(units --compact -1 "$PGHEIGHT mm" 'in')
   PGHEIGHT="--page-height $PGHEIGHT -y $PGHEIGHT"
@@ -279,10 +286,6 @@ if [[ $CROP == 1 ]]; then
   PS2PDF_OPTS="-dEPSCrop"
 fi
 
-if [[ $DESKEW == 1 ]]; then
-  DESKEW="--swdeskew=yes"
-fi
-
 if [[ $SKIP_EMPTY_PAGES == 1 && ! -x "$(command -v bc)" ]]; then
   echo >&2 'Warning: `--skip-empty-pages` specified, but `bc` not available. Disabling empty page detection.'
   SKIP_EMPTY_PAGES=0