1 files changed, 53 insertions, 0 deletions
diff --git a/scripts/convert_maps.sh b/scripts/convert_maps.sh
new file mode 100755
index 0000000..32ef029
--- /dev/null
+++ b/scripts/convert_maps.sh
@@ -0,0 +1,53 @@
+#!/bin/bash
+# Convert a huge .png file into smaller chunks for LeafletJS.
+#
+# Copyright (C) 2020  Markus Koch <markus@notsyncing.net> 
+#
+# This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+# You can obtain a copy of the license at https://mozilla.org/MPL/2.0/.
+
+# TODO: The width of the input png has to be a multiple of TILESIZE, otherwise bad things will happen.
+#       Workaround for now is to add white borders on the bottom and right:
+#         `convert $MAPFILE -extent ${crop}x${crop} -gravity NorthWest $MAPFILE.scaled.png`
+
+TILESIZE=256
+MAPNAME="world-2020-04-09"
+MAPFILE="../$MAPNAME.png"
+
+width=`file "$MAPFILE" | sed -n "s/.* \([0-9]\+\) x \([0-9]\+\).*/\1/p"`
+crop=$TILESIZE
+zoom=0
+
+while true; do
+	out="$MAPNAME/$zoom"
+	tempfile=$out/temp.png
+	
+	echo ""
+	echo "Generating maps for zoomlevel $zoom to $out..."
+		
+	mkdir -p $out;
+	
+	if [ ! -f "$tempfile" ]; then
+		if [ $crop -ge $width ]; then
+			echo "  Reached max zoom at zoomlevel $zoom [using original zoom]"
+			cp $MAPFILE $tempfile
+			#convert $MAPFILE -extent ${crop}x${crop} -gravity NorthWest $tempfile
+		else
+			echo "  Scaling map for zoomlevel $zoom"
+			convert $MAPFILE -resize ${crop}x${crop} $tempfile
+		fi
+	else
+		echo "  Reusing existing scaled image"
+	fi
+
+	echo "  Generating tiles..."
+	convert $tempfile -crop ${TILESIZE}x${TILESIZE} +adjoin $out/%05d.png
+	
+	rm $tempfile
+	
+	if [ $crop -ge $width ]; then
+		break;
+	fi
+	crop=$(($crop * 2))
+	zoom=$(($zoom + 1))
+done;