takeScreenshots

#!/usr/bin/env bash
# Produces a bunch of `cmatrix` screenshots and screencasts.
# This script requires X and the following:
#apt-get install rxvt byzanz

# NOTE We use rxvt, as we can get a screenshot without fuss (scrollbars, menu, ...),
#   it is fairly simple,
#   and it supports X fonts (unlike xterm and uxterm).
TERM_EMULATOR_BASE="rxvt +sb"

CAPTURES_DIR="data/img"

# Function to take a single cmatrix screenshot (takes about 3.5s to execute)
# or optionally, a screencast of choosable length.
captureCMatrix() {
	CAPTURE_FILE="$1"
	CMATRIX_OPTIONS="$2"
	# If 0 (default if no 3rd param is given),
	# we make a screenshot instead of a screencast.
	SCREENCAST_DURATION="${3:-0}"

	if [ "${SCREENCAST_DURATION}" -gt 0 ]
	then
		KILL_DELAY="$((SCREENCAST_DURATION + 1))"
		CAPTURE_FILE="${CAPTURE_FILE}.gif"
	else
		KILL_DELAY=3
		CAPTURE_FILE="${CAPTURE_FILE}.png"
	fi
	WINDOW_TITLE="CMatrix capture ${CAPTURE_FILE}"

	# NOTE the "-PIPE" prevents output of the "Terminated: ..." message
	( cmdpid=$BASHPID; ( sleep "${KILL_DELAY}"; kill -PIPE "$cmdpid" ) & exec ${TERM_EMULATOR_BASE} -name "${WINDOW_TITLE}" -title "${WINDOW_TITLE}" -e bash -c "
		if [ ${SCREENCAST_DURATION} -gt 0 ]
		then
			# Take screencast (animated GIF)

			# Get this windows X-window-info
			myXwininfo=\$(xwininfo -name \"${WINDOW_TITLE}\")
			# Extract location and size
			read X < <(awk -F: '/Absolute upper-left X/{print \$2}' <<< \"\$myXwininfo\")
			read Y < <(awk -F: '/Absolute upper-left Y/{print \$2}' <<< \"\$myXwininfo\")
			read W < <(awk -F: '/Width/{print \$2}' <<< \"\$myXwininfo\")
			read H < <(awk -F: '/Height/{print \$2}' <<< \"\$myXwininfo\")
			# Record a screencast as gif
			byzanz-record -c --delay=0 --duration=${SCREENCAST_DURATION} --x=\$X --y=\$Y --width=\$W --height=\$H "${CAPTURE_FILE}" &
		else
			# Take screen-shot (PNG image)

			# Take screenshot in 2 seconds
			( sleep 2 ; xwd -nobdrs -name \"${WINDOW_TITLE}\" -silent | xwdtopnm 2> /dev/null | pnmtopng 2> /dev/null > ${CAPTURE_FILE} ) &
		fi

		# Run cmatrix until the process gets killed
		cmatrix ${CMATRIX_OPTIONS}
		" )
}

CMD_CS="captureCMatrix"
CAPTURE_FILE_BASE="${CAPTURES_DIR}/capture_"
mkdir -p "${CAPTURES_DIR}"

# Capture a screen session ("video"/animated GIF)
${CMD_CS} "${CAPTURE_FILE_BASE}orig" "-xba" "5"
${CMD_CS} "${CAPTURE_FILE_BASE}rainbow" "-xbar" "5"

# From here on, we take several screenshots with different arguments.
${CMD_CS} "${CAPTURE_FILE_BASE}default" ""
${CMD_CS} "${CAPTURE_FILE_BASE}bold" "-b"
${CMD_CS} "${CAPTURE_FILE_BASE}bold_font" "-bx"
for color in green red blue white yellow cyan magenta black
do
	${CMD_CS} "${CAPTURE_FILE_BASE}bold_C_${color}" "-b -C ${color}"
done
${CMD_CS} "${CAPTURE_FILE_BASE}bold_rainbow" "-b -r"