keystroke-animator

#!/usr/bin/env bash
set -e

# Join an array as delimited string.
# http://stackoverflow.com/a/17841619
function join { local IFS="$1"; shift; echo -E "$*"; }

function translateOnMac {
	local char="$1"
	shift

	# List key codes:
	# http://apple.stackexchange.com/questions/36943/how-do-i-automate-a-key-press-in-applescript
	# http://apple.stackexchange.com/a/36947
	# grep '^ *kVK' /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Headers/Events.h|tr -d ,|while read x y z;do printf '%d %s %s\n' $z $z ${x#kVK_};done|sort -n

	if [[ "$char" == "\"" ]];
	then # 39 0x27 ANSI_Quote
		echo "key code 39 using {shift down}"
	elif [[ "$char" == $'\n' ]];
	then # 36 0x24 Return
		echo "key code 36"
	else
		echo "keystroke \"${char}\""
	fi
}

function keystrokeOnMac {
	local char="$1"
	shift

	local translated=$(translateOnMac "$char")

	echo "tell application \"System Events\" to ${translated}" | osascript
}

function keystroke {
	local char="$1"
	shift

	# TODO: other platforms?
	keystrokeOnMac "$char"
}

function display {
	echo -nE "$char"
}

function animator {
	local animationOutputFilename="output.gif"
	local -a filesAndSettings

	while IFS= read -r -d '' file;
	do
		delay=$(echo "$file" | sed 's/.*_t\([[:digit:]][[:digit:]]*\).*/\1/g')

		# 100 imagemagick ticks per seconds
		filesAndSettings+=("-delay")
		filesAndSettings+=("${delay}x100")
		filesAndSettings+=("${file}")
		filesAndSettings+=("-alpha")
		filesAndSettings+=("remove")
	done

	convert -background "white" -alpha remove "${filesAndSettings[@]}" -layers "optimize" -loop 0 "$animationOutputFilename"
}

read -d '' getActiveWindowIdOnMacScript <<-'EOF' || true
	tell application "System Events"
		set frontApp to name of first application process whose frontmost is true
	end tell
	tell app frontApp to id of front window
EOF

function getActiveWindowIdOnMac {
	echo "$getActiveWindowIdOnMacScript" | osascript
}

function getActiveWindowId {
	# TODO: other platforms?
	getActiveWindowIdOnMac
}

function screenshotOnMac {
	local filename="${1}"
	shift

	local activeWindowId=$(getActiveWindowId)

	if [[ "$config_withShadow" == "false" ]];
	then
		screencapture -o "-l${activeWindowId}" "$filename"
	else
		screencapture "-l${activeWindowId}" "$filename"
	fi
}

function screenshot {
	local index=$(printf "%05d" "$1")
	shift
	local seconds="${1:-0.05}"
	shift

	# 100 imagemagick ticks per seconds
	local -i ticks="$(echo "${seconds} * 100" | bc | sed 's/\..*$//g')"

	local filename="keystroke-animator_i${index}_t${ticks}.png"

	screenshotOnMac "$filename"

	echo "${filename}"
}

function typeKeysFromStdin {
	local -r keySleep="${1:-0.05}"
	shift
	local -r lineSleep="${1:-1.0}"
	shift

	local screenshotList="screenshot-filelist.txt"
	local -i screenshotIndex=0
	local sleepSeconds
	local -a screenshotFiles

	[[ -s "$screenshotList" ]] && rm "$screenshotList"
	touch "$screenshotList"

	# Screenshot the initial state.
	screenshot $(( screenshotIndex++ )) "$lineSleep" >>"$screenshotList"

	while IFS= read -d '' -n 1 char; do
		if [[ "$char" == $'\n' ]];
		then
			sleepSeconds="$lineSleep"

			# Screenshot before and after return key.
			# This allows typed terminal commands to be perceived before they flash by.
			screenshot $(( screenshotIndex++ )) "$sleepSeconds" >>"$screenshotList"
		else
			sleepSeconds="$keySleep"
		fi

		display "$char"
		keystroke "$char"

		sleep "$sleepSeconds"
		screenshot $(( screenshotIndex++ )) "$sleepSeconds" >>"$screenshotList"
	done

	# Screenshot final state, and hold for a while.
	screenshot $(( screenshotIndex++ )) $(echo "5 * ${lineSleep}" | bc) >>"$screenshotList"

	cat "$screenshotList" | tr '\n' '\0' | animator
}

function keystroker {
	if [[ "$1" == "--no-shadow" ]];
	then
		config_withShadow="false"
		shift
	fi

	local -ri countdown="${1:-5}"
	shift || true
	local -r keySleep="${1:-0.05}"
	shift || true
	local -r lineSleep="${1:-1.0}"
	shift || true

	echo "keystroker: Now focus the window you want the typing to go in!"
	for i in $(seq "$(( countdown - 1 ))" 0);
	do
		echo "keystroker: ${i}..."
		sleep 1
	done

	echo "keystroker: Keystrokes are echoed in this window:"
	typeKeysFromStdin "$keySleep" "$lineSleep"
	echo "keystroker: End of input."
}

function main {
	if [[ "$1" == "--animator" ]];
	then
		shift
		animator "$@"
	else
		keystroker "$@"
	fi
}

declare config_withShadow="true"

main "$@"