From e3cbf1bcbbc5b7181bb69171d108a2710a74a90d Mon Sep 17 00:00:00 2001
From: Oleg Pudeyev <code@olegp.name>
Date: Mon, 26 Jul 2021 21:27:30 -0400
Subject: [PATCH 1/2] Omit --mode argument when its value is the empty string

---
 scan | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scan b/scan
index bb49042..7798566 100755
--- a/scan
+++ b/scan
@@ -245,7 +245,10 @@ fi;
 
 echo >&2 "Scanning..."
 #eval strace -f -o /tmp/scan-trace.txt scanadf -d $DEVICE $MAXPAGE $PGHEIGHT $PGWIDTH -S $SCRIPT --script-wait --resolution $RESOLUTION --mode $MODE $DESKEW $CROP $SOURCE -o scan-%04d
-eval scanadf -d \'"$DEVICE"\' $MAXPAGE $PGHEIGHT $PGWIDTH -S $SCRIPT --script-wait --resolution $RESOLUTION --mode $MODE $DESKEW $CROP $DRIVER_OPTION $SOURCE -o $TMP_DIR/scan-%04d
+if test -n "$MODE"; then
+  mode="--mode $MODE"
+fi
+eval scanadf -d \'"$DEVICE"\' $MAXPAGE $PGHEIGHT $PGWIDTH -S $SCRIPT --script-wait --resolution $RESOLUTION $MODE $DESKEW $CROP $DRIVER_OPTION $SOURCE -o $TMP_DIR/scan-%04d
 
 shopt -s extglob nullglob
 pdffiles=($TMP_DIR/scan-[0-9]*.pdf)

From 9ef32aef3f2001d79c6144c67688d5b9f4fabbbb Mon Sep 17 00:00:00 2001
From: Oleg Pudeyev <code@olegp.name>
Date: Tue, 27 Jul 2021 10:47:28 -0400
Subject: [PATCH 2/2] add --mode-hw-default option

---
 README.md |  4 +++-
 scan      | 21 +++++++++++++++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 6d52b78..d627b3e 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,9 @@ OPTIONS
  -d, --duplex
    Duplex scanning
  -m, --mode
-   Mode e.g. Lineart (default), Halftone, Gray, Color, etc.
+   Mode e.g. Lineart (default), Halftone, Gray, Color, etc. Use --mode-hw-default to not set any mode
+ --mode-hw-default
+   Do not set the mode explicitly, use the hardware default
  -r, --resolution
    Resolution e.g 300 (default)
  -a, --append
diff --git a/scan b/scan
index 7798566..cb06317 100755
--- a/scan
+++ b/scan
@@ -10,6 +10,8 @@ USEARRAY=0
 APPEND=0
 RESOLUTION=300
 MODE=Lineart
+MODE_CHANGED=0
+MODE_HW_DEFAULT=0
 SCRIPT="$DIR/scan_perpage"
 DUPLEX=0
 UNPAPER=0
@@ -45,7 +47,9 @@ while [[ $# > 0 ]]; do
 
   -d|--duplex) DUPLEX=1 ;;
 
-  -m|--mode) shift; MODE=$1 ;;
+  -m|--mode) shift; MODE=$1; MODE_CHANGED=1 ;;
+
+  --mode-hw-default) shift; MODE_HW_DEFAULT=1 ;;
 
   -r|--resolution) shift; RESOLUTION=$1 ;;
 
@@ -100,7 +104,9 @@ if [[ $HELP == 1 ]]; then
   echo " -d, --duplex"
   echo "   Duplex scanning"
   echo " -m, --mode"
-  echo "   Mode e.g. Lineart (default), Halftone, Gray, Color, etc."
+  echo "   Mode e.g. Lineart (default), Halftone, Gray, Color, etc. Use --mode-hw-default to not set any mode"
+  echo " --mode-hw-default"
+  echo "   Do not set the mode explicitly, use the hardware default"
   echo " -r, --resolution"
   echo "   Resolution e.g 300 (default)"
   echo " -a, --append"
@@ -148,6 +154,11 @@ if [[ $USEARRAY == 1 && $USEOUTPUT == 1 ]]; then
   exit 1
 fi
 
+if [[ $MODE_CHANGED == 1 && $MODE_HW_DEFAULT == 1 ]]; then
+  echo >&2 "Use one of --mode or --mode-hardware-default. Aborting."
+  exit 1
+fi
+
 if [[ $USEOUTPUT == 1 && "$OUTPUT" == "" ]]; then
   echo >&2 "Output file must be specified. Aborting."
   exit 1
@@ -245,8 +256,10 @@ fi;
 
 echo >&2 "Scanning..."
 #eval strace -f -o /tmp/scan-trace.txt scanadf -d $DEVICE $MAXPAGE $PGHEIGHT $PGWIDTH -S $SCRIPT --script-wait --resolution $RESOLUTION --mode $MODE $DESKEW $CROP $SOURCE -o scan-%04d
-if test -n "$MODE"; then
-  mode="--mode $MODE"
+if [[ $MODE_HW_DEFAULT == 1 ]]; then
+  MODE=
+else
+  MODE="--mode $MODE"
 fi
 eval scanadf -d \'"$DEVICE"\' $MAXPAGE $PGHEIGHT $PGWIDTH -S $SCRIPT --script-wait --resolution $RESOLUTION $MODE $DESKEW $CROP $DRIVER_OPTION $SOURCE -o $TMP_DIR/scan-%04d