Add gitignore, fetch script, and postprocess script

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

postprocess.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+# Postprocesses all fetched comics from the fetch-comics.py file
+set -euo pipefail
+
+HERE="$(dirname "$0")"
+DATA_DIR="$HERE/data"
+IMAGE_DIR="$DATA_DIR/images"
+OUT_DIR="$HERE/out"
+#alt_json="$HERE/alt_text.json"
+alt_json="$DATA_DIR/alt_text.json"
+
+if [[ ! -f "$alt_json" ]]; then
+    echo "Could not find $alt_json - have you run the fetch script?"
+    exit 1
+fi
+
+mkdir -vp "$OUT_DIR"
+
+# Get the list of all comic dates
+readarray -t dates < <(jq -r 'keys[]' < "$alt_json")
+
+#echo ${#dates[@]}
+for date in "${dates[@]}"; do
+    echo -n "Processing comic $date ... "
+    image_in="$IMAGE_DIR/$date.gif"
+    image_out="$OUT_DIR/$date.png"
+    if [[ -f "$image_out" ]]; then
+        echo "already exists, skipping"
+        continue
+    fi
+    alt_text="$(jq -r ".[\"$date\"]" < "$alt_json")"
+
+    if [[ -z "$alt_text" ]]; then
+        convert "$image_in" \
+            -background white -alpha background \
+            "$image_out"
+    else
+        convert "$image_in" \
+            -background white -alpha background \
+            -gravity center \
+            -pointsize 12 -size 360x caption:"$alt_text" \
+            -append \
+            "$image_out"
+    fi
+
+    echo "OK"
+done