Circle Images

This script uses ImageMagick, a powerful command-line image processing tool. You must have it installed for this script to work.

The Bash Script

You can save this code as circularize.sh.

#!/bin/bash

# A script to convert an image into a circular one with a transparent background.
#
# DEPENDENCY: ImageMagick (must be installed)
# USAGE: ./circularize.sh /path/to/your/image.jpg

# --- Configuration ---
# Use 'magick' (ImageMagick v7+) or 'convert' (v6 or legacy)
# By default, we check for 'magick' first.
if command -v magick &> /dev/null; then
    IM_COMMAND="magick"
elif command -v convert &> /dev/null; then
    IM_COMMAND="convert"
else
    echo "Error: ImageMagick is not installed." >&2
    echo "Please install ImageMagick (https://imagemagick.org) to use this script." >&2
    exit 1
fi

# --- Input Validation ---
if [ -z "$1" ]; then
    echo "Usage: $0 <input_image>" >&2
    exit 1
fi

INPUT_FILE="$1"

if [ ! -f "$INPUT_FILE" ]; then
    echo "Error: File not found: $INPUT_FILE" >&2
    exit 1
fi

# --- File Naming ---
# Get the input file's directory and base name
DIRNAME=$(dirname -- "$INPUT_FILE")
INPUT_BASENAME=$(basename -- "$INPUT_FILE")

# Remove the old extension (e.g., .jpg, .png)
FILENAME_NO_EXT="${INPUT_BASENAME%.*}"

# Define the output file path
OUTPUT_FILE="${DIRNAME}/${FILENAME_NO_EXT}_circular.png"

echo "Processing '$INPUT_FILE'..."

# --- Get Image Dimensions ---
# Get dimensions as a single "widthxheight" string
DIMS=$($IM_COMMAND identify -format "%wx%h" "$INPUT_FILE")
# Split into width and height
WIDTH=$(echo $DIMS | cut -dx -f1)
HEIGHT=$(echo $DIMS | cut -dx -f2)

# Determine the smallest dimension to create a square crop
if [ $WIDTH -lt $HEIGHT ]; then
    SIZE=$WIDTH
else
    SIZE=$HEIGHT
fi

# Calculate the center coordinate (half the size)
# This is used for drawing the circle
C=$(($SIZE / 2))

# --- ImageMagick Command ---
# This is the core logic
$IM_COMMAND "$INPUT_FILE" \
    -alpha set \
    -gravity center \
    -crop ${SIZE}x${SIZE}+0+0 +repage \
    \( \
        +clone \
        -channel A -evaluate set 0 \
        -fill white \
        -draw "circle $C,$C $C,0" \
    \) \
    -compose DstIn \
    -composite \
    "$OUTPUT_FILE"

# --- Final Check ---
if [ $? -eq 0 ]; then
    echo "✅ Success! Circular image saved to: $OUTPUT_FILE"
else
    echo "❌ Error: ImageMagick command failed." >&2
    exit 1
fi

How to Use It

Install ImageMagick:
- Fedora/RHEL: sudo dnf install ImageMagick
Save the Script:
Copy the code above and save it to a file named circularize.sh.
Make it Executable:
In your terminal, navigate to where you saved the file and run:
```
chmod +x circularize.sh
```

Run the Script:
Pass the path to your image as an argument:

./circularize.sh my_photo.jpg

Or:

./circularize.sh /home/user/pictures/avatar.png

If you provided my_photo.jpg, the script will create a new file named my_photo_circular.png in the same directory.

How the ImageMagick Command Works

Here's a breakdown of the main command:

$IM_COMMAND "$INPUT_FILE": Loads your input image.
-alpha set: Ensures the image has a transparency (alpha) channel, even if it's a JPG.
-gravity center -crop ${SIZE}x${SIZE}+0+0 +repage:
- -gravity center: Sets the "anchor" point for the crop to the center.
- -crop ${SIZE}x${SIZE}+0+0: Crops the image into a square based on the smallest dimension ($SIZE).
- +repage: Resets the image's "page" geometry, which is necessary after cropping.
$ ... $: This starts an in-memory "sub-process". We are building a mask inside these parentheses.
+clone: Makes a copy of our (now square) image. This copy will become the mask.
-channel A -evaluate set 0: Selects the alpha channel (A) of the clone and sets it to 0 (fully transparent).
-fill white -draw "circle $C,$C $C,0": Draws a solid white circle onto the transparent clone. The circle's center is at $C,$C and one edge is at $C,0 (the top-middle edge).
\): The sub-process is done. We now have two images in memory: the original cropped photo and our white-circle-on-transparent-background mask.
-compose DstIn -composite: This is the magic.
- -compose DstIn: Sets the composition method to "Destination In".
- -composite: Applies the composition. It keeps the parts of the Destination (our photo) that are In the Source (our white circle mask).
"$OUTPUT_FILE": Saves the final result to the output PNG file.

#Circle Images

#The Bash Script

#How to Use It

#How the ImageMagick Command Works

Circle Images

The Bash Script

How to Use It

How the ImageMagick Command Works