panofyForFacebook

#!/usr/bin/env bash
# Adds metadata to images so that Facebook displays them as panoramas.
# https://discuss.pixls.us/t/panorama-mode-in-facebook/3585
# By Harry Durgin and Morgan Hardwood

if [[ ! -f ${1} ]]; then
    printf '%s\n' "No input file specified or file not found." "Aborting."
    exit 1
fi

hfov=0
while [[ hfov -lt 100 || hfov -gt 360 ]]; do
    read -r -p "Enter horizontal field of view (100-360): " hfov
done

for f in "${@}"; do
    printf '%s\n' "" "Processing: $f"

    width="$(exiftool -T -ImageWidth "${f}")"
    height="$(exiftool -T -ImageHeight "${f}")"
    ratio=$((width/height))

    if [[ ratio -lt 2 ]]; then
        printf '%s\n' "Image must have a ratio of at least 2:1." "Skipping."
        continue
    fi

    width_full=$((360*width/hfov))
    height_full=$((180*width_full/hfov))
    height_full=$((width_full/2))
    left_crop=$(((width_full-width)/2))
    top_crop=$(((height_full-height)/2))

    exiftool \
        -overwrite_original \
        -FullPanoWidthPixels="$width_full" \
        -FullPanoHeightPixels="$height_full" \
        -CroppedAreaLeftPixels="$left_crop" \
        -CroppedAreaTopPixels="$top_crop" \
        -CroppedAreaImageWidthPixels="$width" \
        -CroppedAreaImageHeightPixels="$height" \
        -ProjectionType=equirectangular \
        -UsePanoramaViewer=True \
        "$f"
done