initial commit

diff --git a/xkcd-annotator.sh b/xkcd-annotator.sh
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+#!/bin/bash
+
+# annotate xkcd comics with title and alt-text
+# copyright Felix Kästner (fpunktk), GPL
+# expected fileformat: [^-]*-[0-9]+-.*\.(jpg|png)
+
+title_font="/usr/share/fonts/truetype/freefont/FreeSansBold.ttf"
+title_size="26"
+alt_font="/usr/share/fonts/truetype/freefont/FreeSans.ttf"
+alt_size="16"
+sourcedir="./"
+destdir="./xkcd-converted/"
+minwidth="500"
+am="1" # alt-text margin left and right
+
+# change margin for alt-text to manually prevent overflow
+case "$1" in
+    [0-9]|[1-9][0-9])
+        [ $1 -lt $(($minwidth / 10)) ] && am="$1"
+    ;;
+esac
+
+mkdir -pv "$destdir"
+
+for fn in xkcd*.png xkcd*.jpg
+do
+    [ -f "$fn" ] || continue
+    echo "$fn"
+    # get width and height from the original image
+    read cw ch <<<$(identify -format '%w %h' "$fn")
+    w="$cw"
+    [ $w -lt $minwidth ] && w="$minwidth"
+    # extract the number (between the -)
+    nn="${fn#*-}"
+    nn="${nn%%-*}"
+    # download the json with the image information if it does not exist
+    [ -r "$destdir${fn%\.*}.json" ] || wget -q -O "$destdir${fn%\.*}.json" "http://xkcd.com/$nn/info.0.json"
+    json="$(cat "$destdir${fn%\.*}.json")"
+    # extract title-text and alt-text from json (dirty hack, might break things)
+    tt="${json#*\"title\": \"}"
+    tt="${tt%%\", *}"
+    at="${json#*\"alt\": \"}"
+    at="${at%%\", *}"
+    # write title-text (with number) and alt-text to a new png image
+    convert -background white -border 2x0 -bordercolor white -fill black -font "$title_font" -pointsize "$title_size" -size $(($w-4))x -gravity Center caption:"xkcd $nn: $tt" tt.png
+    # TODO: sometimes text gets cut off for no obvious reason, can be prevented by specifying margin $am
+    convert -background '#FFF9BD' -bordercolor '#FFF9BD' -border ${am}x0 -bordercolor black -border 1x1 -fill black -font "$alt_font" -pointsize "$alt_size" -size $(($w-2-$am-$am))x -gravity Center caption:"$at" at.png
+    # get height from the new images
+    th="$(identify -format '%h' tt.png)"
+    ah="$(identify -format '%h' at.png)"
+    echo -e "$nn $w $ch $th $ah \n$tt \n$at \n"
+    # combine the images
+    convert -size ${w}x$(($ch+$th+$ah+5)) "xc:white" tt.png -geometry +0+0 -composite "$fn" -geometry +$((($w-$cw)/2))+$th -composite at.png -geometry +0+$(($th+$ch+5)) -composite "$destdir${fn%\.*}.png"
+    # delete temporary images
+    rm tt.png at.png
+done
+