From 13c40dcfce42f71dbfc32c3078af2d24463215f6 Mon Sep 17 00:00:00 2001
From: Dirk Surmann <4048472+surmann@users.noreply.github.com>
Date: Sat, 1 Jan 2022 13:23:44 +0100
Subject: [PATCH] update brightness and contrast control

---
 scan         | 11 ++++++-----
 scan_perpage | 11 ++++++-----
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/scan b/scan
index 6a4e644..b539283 100755
--- a/scan
+++ b/scan
@@ -32,7 +32,7 @@ DRIVER_OPTION=
 VERBOSE=0
 SKIP_EMPTY_PAGES=0
 WHITE_THRESHOLD=99.8
-BRIGHTNESS=0
+BRIGHTNESS_CONTRAST=
 SOURCE=""
 
 TMP_DIR=$(mktemp -d -p "" scan.XXXXXXXXXX)
@@ -98,7 +98,7 @@ while [[ $# > 0 ]]; do
 
   -xo|--driver-options) shift; DRIVER_OPTION=$1;;
 
-  --brightness) BRIGHTNESS=1 ;;
+  --brightness-contrast-sw) shift; BRIGHTNESS_CONTRAST=$1 ;;
 
   *) if [[ $USEARRAY == 1 ]]; then OUTPUTARR+=("$1"); else echo >&2 "Unknown argument: $1"; exit 1; fi ;;
 
@@ -153,8 +153,9 @@ if [[ $HELP == 1 ]]; then
   echo "   remove empty pages from resulting PDF document (e.g. one sided doc in duplex mode)"
   echo " --white-threshold"
   echo "   threshold to identify an empty page is a percentage value between 0 and 100. The default is 99.8"
-  echo " --brightness"
-  echo "   Increase brightness and contrast in post-processing"
+  echo " --brightness-contrast-sw"
+  echo "   Alter brightness and contrast via post-processing - prefer specifying brightness and/or"
+  echo "   contrast via --driver-options if supported by your hardware."
   echo ""
   echo "OUTPUT"
   echo " -o, --output <outputfile>"
@@ -278,7 +279,7 @@ export PGHEIGHTIN
 export PS2PDF_OPTS
 export SKIP_EMPTY_PAGES
 export WHITE_THRESHOLD
-export BRIGHTNESS
+export BRIGHTNESS_CONTRAST
 
 if [[ $VERBOSE == 1 ]]; then
   LOCKFILE=$(mktemp)
diff --git a/scan_perpage b/scan_perpage
index 5fa4a72..d3a2a74 100755
--- a/scan_perpage
+++ b/scan_perpage
@@ -14,7 +14,7 @@ usage()
   echo "  PGWIDTHIN"
   echo "  PGHEIGHTIN"
   echo "  SKIP_EMPTY_PAGES"
-  echo "  BRIGHTNESS"
+  echo "  BRIGHTNESS_CONTRAST"
   echo "  PS2PDF_OPTS (optional)"
   echo "  VERBOSE (optional)"
   echo "  LOCKFILE (required if VERBOSE=1)"
@@ -51,7 +51,7 @@ if [[ $# < 1 ]]; then
   exit 1
 fi
 
-if [[ "$UNPAPER" == "" || "$SEARCHABLE" == "" || "$RESOLUTION" == "" || "$RESOLUTION" == "" || "$SKIP_EMPTY_PAGES" == "" || "$BRIGHTNESS" == "" ]]; then
+if [[ "$UNPAPER" == "" || "$SEARCHABLE" == "" || "$RESOLUTION" == "" || "$RESOLUTION" == "" || "$SKIP_EMPTY_PAGES" == "" ]]; then
   usage
   exit 1
 fi
@@ -68,11 +68,12 @@ fi
 process_page() {
   log ""
   log "-------------------------------------------------------------------------------"
-  log "Post-processing scanned page ${IMAGE_PATH}, deskew=$UNPAPER, searchable=$SEARCHABLE, skip-empty-pages=$SKIP_EMPTY_PAGES, white-threshold=$WHITE_THRESHOLD, brightness=$BRIGHTNESS..."
+  log "Post-processing scanned page ${IMAGE_PATH}, deskew=$UNPAPER, searchable=$SEARCHABLE, skip-empty-pages=$SKIP_EMPTY_PAGES, white-threshold=$WHITE_THRESHOLD, brightness-contrast-sw=$BRIGHTNESS_CONTRAST..."
   log "-------------------------------------------------------------------------------"
 
-  if [[ $BRIGHTNESS == 1 ]]; then
-    convert "$IMAGE_PATH" -brightness-contrast 20x10 "$IMAGE_PATH"
+  if [[ "$BRIGHTNESS_CONTRAST" != "" ]]; then
+	log "Adjust brightness and contrast in ImageMagick by $BRIGHTNESS_CONTRAST"
+    convert "$IMAGE_PATH" -brightness-contrast $BRIGHTNESS_CONTRAST "$IMAGE_PATH"
   fi
 
   if [[ $SKIP_EMPTY_PAGES == 1 ]]; then