makegif.sh

#!/bin/sh
# ------------------------------------------------------------------------------
# Uses ImageMagick to create an animated GIF from an image sequence and by using 
# a common palette. 
# Note: Providing a palette speeds up the encoding but can be disabled 
# by removing the “remap” option.
# The resulting GIF is passed to “ImageOptim” for filesize reduction. 
# Note: could eventually be replaced with Gifsicle or left out entirely.
#
# ------------------------------------------------------------------------------
# Usage:
# > sh makegif.sh imageFolder palette.png 3
# - imageFolder is a folder containing the images
# - palette.png is a global palette file (1 pixel per color)
# - 3 is the delay bewteen frames in 1/100 seconds (3 ≈ 30 fps)
# - outputs a file like “imageFolder_d3.gif”
#
# Note:
# The images inside the folder should be generated with leading zeroes
# to avoid reordering:
# 000.png, 001.png, 002.png, etc.

FOLDER=$1
PALETTE=$2
DELAY=${3:-3}

convert \
	-delay $DELAY \
	-monitor \
	-dither None \
	-remap $PALETTE \
	-loop 0  \
	"$FOLDER/frames/*.png" "${FOLDER}_d${DELAY}.gif";
	# Uncomment below for an extra ImageOptim pass
	# /Applications/ImageOptim.app/Contents/MacOS/ImageOptim "${FOLDER}_d${DELAY}.gif"

# ------------------------------------------------------------------------------
# Resources:
# https://legacy.imagemagick.org/Usage/quantize/