Adding Text Watermark to Images with Random Rotation using ImageMagick and Docker (Supports CJK)

watermark.md

Adding Text Watermark to Images with Random Rotation using ImageMagick and Docker (Supports CJK)

TL;DR

./watermark.sh input.jpg "僅供 linnil1 使用" output.jpg /OTF/TraditionalChinese/NotoSansCJKtc-Regular.otf

#!/bin/sh
podman run -it --rm \
    -v $4:/font/noto_sans_tc.otf:ro \
    -v $PWD:/app -w /app \
    docker.io/dpokidov/imagemagick \
    \( $1 -strip -interlace Plane -gaussian-blur 0.1 -resize 1500x1500 -quality 90% \) \
    \( -size 1500x1500 xc:none -pointsize 100 -fill "rgba(0,0,0,0.2)" -gravity center -font "/font/noto_sans_tc.otf" \
       -draw "rotate -$((RANDOM % 60)) text 0,0 '$2'" \) \
    -gravity center -composite $3

Requirements

• Docker or Podman installed
• Download a Chinese font, e.g., NotoSansCJK TC

Demo

Before:

After: I changed the color to rgba(255,255,255,0.2) and removed -gaussian-blur 0.1 for better text quality: