Overlay logo over image, resizing logo to x% of the smallest dimension of the image

overlay.sh

#!/bin/bash

# Author: https://github.com/luismrsilva
# (c) 2019 luismrsilva

# Config

## percent of smaller dimension of image
## this size will be used on the largest side of the logo
LOGO_PERCENT=25
LOGO_OFFSET_PERCENT=3

# as per ImageMagic -gravity
# $ convert -list gravity
GRAVITY=southeast

######

if [ "$#" -lt 3 ]; then
	echo "Overlay logo over image, resizing logo to x% of the smallest dimension of the image"
	echo "Usage: $0 <logo> <out_dir> <img> [logo_gravity] [list-file]"
	echo
	echo "    [list-file]	file where to append a line with img and gravity"
	exit 1
fi

if [ "$#"  -gt 3 ]; then
	GRAVITY="$4"
fi

if [ "$#"  -gt 4 ]; then
	LIST_FILE="$5"
fi


LOGO=$1
OUT_DIR=$2
IMG=$3

# echo "LOGO: $LOGO" >&2
# echo "OUT_DIR: $OUT_DIR" >&2
# echo "IMG: $IMG" >&2


function getImgDim(){
	identify -format '%wx%h' "$1"
}

function getDimW(){
	echo "$1" | cut -d "x" -f1
}

function getDimH(){
	echo "$1" | cut -d "x" -f2
}

LOGO_DIM=$(getImgDim $LOGO)
LOGO_DIM_W=$(getDimW $LOGO_DIM)
LOGO_DIM_H=$(getDimH $LOGO_DIM)

IMG_DIM=$(getImgDim $IMG)
IMG_DIM_W=$(getDimW $IMG_DIM)
IMG_DIM_H=$(getDimH $IMG_DIM)


# echo Logo: ${LOGO_DIM_W}x${LOGO_DIM_H}
# echo IMG:  ${IMG_DIM_W}x${IMG_DIM_H}


# get min(w, h)
if [ "$IMG_DIM_W" -gt "$IMG_DIM_H" ]; then
	IMG_MIN_DIM=$IMG_DIM_H
else
	IMG_MIN_DIM=$IMG_DIM_W
fi

LOGO_OUT_DIM=$((LOGO_PERCENT*IMG_MIN_DIM/100))
LOGO_OUT_OFFSET=$((LOGO_OFFSET_PERCENT*IMG_MIN_DIM/100))

# echo "LOGO_OUT_DIM=$LOGO_OUT_DIM"
# echo "LOGO_OUT_OFFSET=$LOGO_OUT_OFFSET"
# echo "GRAVITY=$GRAVITY"

BASENAME=$(basename "$IMG")
echo "BASENAME: $BASENAME"

OUT=$(echo $OUT_DIR/$BASENAME)

echo "Out: $OUT"

# note: the -resize option resizes the image to fit inside a rectangle, preserving AR.

mkdir -p "$OUT_DIR"

convert "$IMG" -auto-level -auto-orient \( "$LOGO" -resize ${LOGO_OUT_DIM}x${LOGO_OUT_DIM} \) -gravity $GRAVITY -geometry +$LOGO_OUT_OFFSET+$LOGO_OUT_OFFSET -composite $OUT


if [ "$?" -eq "0" ] && ! [ "$LIST_FILE" == "" ]; then
	echo "$IMG	$GRAVITY" | tee -a "$LIST_FILE"
fi