Create scrolling text gifs for Slack

README.md

(Forked from yolo.sh that works on mac)

Makes little scrolly text jiffs in Flywheel colors.

Prerequisites

• imagemagick sudo apt install imagemagick
• gifsicle sudo apt install gifsicle
• u linux

Usage

usage: ./yolo.sh [options] <message>

Options:

  -h                Show this help message

  -o <output.gif>   Path to output gif. Default: output.gif

  -c <color>        Choose color set, valid options are:
                    red, orange, yellow, green, blue, purple,
                    pink, black, white.  Default: blue

  -d <delay>        Delay between frames. Default: 6

  -s <step>         How many pixels to step each frame. Default: 10

  -H <height>       Image height. Default: 128

  -f <font name>    The font name. Default: helvetica

 -w                 Force white text color

Examples

$ yolo.sh -c orange -o gtfo.gif GTFO

yolo.sh

#!/usr/bin/env bash

contains() {
  local e
  for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
  return 1
}

usage() {
  if [ "$1" != "" ]; then
    echo -e "Error: $1\n" >&2
  fi
  echo "usage: $0 [options] <message>"
  echo
  echo "Options:"
  echo
  echo "  -h                Show this help message"
  echo
  echo "  -o <output.gif>   Path to output gif. Default: output.gif"
  echo
  echo "  -c <color>        Choose color set, valid options are:"
  echo "                    red, orange, yellow, green, blue, purple,"
  echo "                    pink, black, white.  Default: blue"
  echo
  echo "  -d <delay>        Delay between frames. Default: 6"
  echo
  echo "  -s <step>         How many pixels to step each frame. Default: 10"
  echo
  echo "  -H <height>       Image height. Default: 128"
  echo
  echo "  -f <font name>    The font name. Default: helvetica"
  echo
  echo " -w                 Force white text color"
  exit 1
}


VALID_COLORS=("red" "orange" "yellow" "green" "blue" "purple" "pink" "black" "white")
COLOR="black"
OUTPUT="output.gif"
FONT_NAME="helvetica"
FORCE_WHITE_TEXT=0
SPEED=16
DELAY=6
HEIGHT=128

while getopts ":c:o:f:s:d:H:hw" opt; do
  case $opt in
    h)
      usage
      ;;
    w)
      FORCE_WHITE_TEXT=1
      ;;
    c)
      if contains "$OPTARG" "${VALID_COLORS[@]}"; then
        COLOR="$OPTARG"
      else
        usage "Invalid color: $OPTARG"
      fi
      ;;
    o)
      OUTPUT="$OPTARG"
      ;;
    H)
      HEIGHT="$OPTARG"
      ;;
    f)
      FONT_NAME="$OPTARG"
      ;;
    d)
      DELAY="$OPTARG"
      ;;
    s)
      SPEED="$OPTARG"
      ;;
    \?)
      usage "Invalid option: -$OPTARG"
      ;;
    :)
      usage "Option -$OPTARG requires an argument."
      exit 1
      ;;
  esac
done

shift $((OPTIND - 1))

# Find our font before we do anything.
FONT_PATH="$( fc-match "${FONT_NAME}" -f'%{file}' )"
if [ "$FONT_PATH" == "" ]; then
  usage "Could not find '${FONT_NAME}' font. Is it installed?"
else
  echo "Using ${FONT_PATH} for ${FONT_NAME} font."
fi

MESSAGE="$*"
if [ "$MESSAGE" == "" ]; then
  usage "A message is required."
fi

case $COLOR in
  red)
    BACKGROUND="#ef4e65"
    FILL="#8c2738"
    ;;
  orange)
    BACKGROUND="#f47820"
    FILL="#8e4402"
    ;;
  yellow)
    BACKGROUND="#f0ce15"
    FILL="#947c00"
    ;;
  green)
    BACKGROUND="#51bb7b"
    FILL="#267048"
    ;;
  blue)
    BACKGROUND="#50c6db"
    FILL="#01516e"
    ;;
  purple)
    BACKGROUND="#8351a0"
    FILL="#4e2760"
    ;;
  pink)
    BACKGROUND="#e0368c"
    FILL="#851252"
    ;;
  black)
    BACKGROUND="#ffffff"
    FILL="#111111"
    ;;
  white)
    BACKGROUND="#ffffff"
    FILL="#000000"
    ;;
esac

if [ "$FORCE_WHITE_TEXT" == 1 ]; then
  FILL="#ffffff"
fi

# Make a "unique" prefix for this run
PREFIX="$(head -c 32 /dev/urandom  | shasum | cut -b 1-10)"

# Generate image from text input
convert -background "$BACKGROUND" -fill "$FILL" -font "$FONT_PATH" -density 200 -pointsize 100 "label:${MESSAGE}" "/tmp/${PREFIX}_label.png"

# Resize to 128px high
convert -resize x${HEIGHT} "/tmp/${PREFIX}_label.png" "/tmp/${PREFIX}_sized.png"

# Add white space to front and back for empty frames
WIDTH="$(identify -format "%[fx:w]" "/tmp/${PREFIX}_sized.png")"
CANVAS_SIZE=$((WIDTH + HEIGHT + HEIGHT + (HEIGHT / 4))) # HEIGHT in front, HEIGHT / 4 in back
convert -size ${CANVAS_SIZE}x${HEIGHT} "xc:$BACKGROUND" "/tmp/${PREFIX}_canvas.png"
convert "/tmp/${PREFIX}_canvas.png" "/tmp/${PREFIX}_sized.png" -geometry +"${HEIGHT}"+0 -composite "/tmp/${PREFIX}_padded.png"

# Generate individual frames
STEP=$((HEIGHT / (64 / SPEED)))
OFFSET=0
I=0
LIMIT=$((CANVAS_SIZE - HEIGHT))
while [[ "$OFFSET" -lt "$LIMIT" ]]; do
  convert "/tmp/${PREFIX}_padded.png" -crop "${HEIGHT}x${HEIGHT}+${OFFSET}+0!" "$(printf "/tmp/${PREFIX}_frame_%05d.png" $I)"
  I=$((I + 1))
  OFFSET=$((OFFSET + STEP))
done

# Compile to gif
convert -delay "$DELAY" -loop 0 "/tmp/${PREFIX}_frame_*.png" "$OUTPUT"

# Smush it
gifsicle -bO "$OUTPUT"

# Clean up!
rm /tmp/${PREFIX}_*.png

For macos users with homebrew:

brew install fontconfig imagemagick gifsicle