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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Custom Tile Server\n",
    "\n",
    "This example implements a minimal map tile server that serves map tiles from two different basemaps in a chess board pattern."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from multiprocessing import Process\n",
    "\n",
    "from flask import Flask, Response\n",
    "from requests import get as fetch\n",
    "from ipyleaflet import Map, basemaps"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Build and Run a Tile Server"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "app = Flask(__name__)\n",
    "\n",
    "@app.route(\"/scramble/<int:z>/<int:x>/<int:y>\")\n",
    "def scramble(z, x, y):\n",
    "    \"Serve scrambled tiles from two basemaps.\"\n",
    "\n",
    "    urls = [basemaps.Esri[name]['url'] for name in ['WorldStreetMap', 'WorldTopoMap']]\n",
    "    url = urls[(x + y) % 2].format(x=x, y=y, z=z)\n",
    "    img = fetch(url).content\n",
    "    return Response(img, mimetype='image/png')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "p = Process(target=app.run)\n",
    "p.start()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Show a \"Scrambled Tiles\" Map"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "url = 'http://localhost:5000/scramble/{z}/{x}/{y}'\n",
    "bm = {'url': url, 'attribution': 'Scrambled Tiles'}\n",
    "Map(center=(48.86, 2.34), level=10, basemap=bm)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Stop the Tile Server"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "p.kill()"
   ]
  }
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