odesa_aerofoto_proxy

proxy.js

var express = require('express');
var Promise = require('promise');
var rp = require('request-promise'); 
var Jimp = require("jimp");
var Canvas = require('canvas')
  , Image = Canvas.Image
  , canvas = new Canvas(200, 200, "png")
  , ctx = canvas.getContext('2d');


var app = express();

function getImageUrl(z, x, y) {
  var url = "http://195.138.92.34:6080/arcgis/rest/services/Aerofoto/MapServer/WMTS/tile/1.0.0/Aerofoto/default/default028mm/" + z + '/' + y + '/' + x;
  console.log(url);
  return url;
}

function merge4(leftTop, rightTop, leftBottom, rightBottom) {
  var lT, rT, lB, rB, a;
  lt = Jimp.read(leftTop);
  rt = Jimp.read(rightTop);
  lb = Jimp.read(leftBottom);
  rb = Jimp.read(rightBottom);
  return Promise.all([lt, rt, lb, rb]).then(function (images) {
    lt = images[0];
    rt = images[1];
    lb = images[2];
    rb = images[3];
    a = lt.bitmap.width;
    return new Jimp(a * 2, a * 2);
  }).then(function(image) {
    return image
      .blit(lt, 0, 0)
      .blit(rt, a, 0)
      .blit(lb, 0, a)
      .blit(rb, a, a);
  })
}

function scale(image, fx, fy) {
  var w = image.bitmap.width * fx;
  var h = image.bitmap.height * fy;
  return image.resize(w, h);
}

function getBuffer(jimpImage) {
  return new Promise(function(resolve, reject) {
    jimpImage.getBuffer(Jimp.MIME_JPEG, function(err, buffer) {
      if(!err) {
        resolve(buffer);
      } else {
        reject(err);
      }
    });
  });
}

function getTileBytes(z, xOsm, yOsm, scaleFactorX, scaleFactorY) {
  var osmTileWidth = 256, osmTileHeight = 256;

  var xOsm0 = 38340.35295573333 * 2 * 2 * 2 * 2;
  //var xAero0 = 8287.7175 * 5;
  var xAero0 = 8287.7175 * 20;
  var xRelOsm = xOsm - xOsm0;
  var xRelAero = xRelOsm / scaleFactorX;
  var xAero = xRelAero + xAero0; // fractional tile number

  console.log("xAero = " + xAero);

  var yOsm0 = 23149.52 * 2 * 2 * 2 * 2;
  //var yAero0 = 14742.299 * 5;
  //var yAero0 = 14742.304 * 5;
  var yAero0 = 14742.304 * 20;
  var yRelOsm = yOsm - yOsm0;
  var yRelAero = yRelOsm / scaleFactorY;
  var yAero = yRelAero + yAero0;

  console.log("yAero = " + yAero);

  var jpg1 = getImageUrl(z, Math.floor(xAero), Math.floor(yAero));
  var jpg2 = getImageUrl(z, Math.floor(xAero + 1), Math.floor(yAero));
  var jpg3 = getImageUrl(z, Math.floor(xAero), Math.floor(yAero) + 1);
  var jpg4 = getImageUrl(z, Math.floor(xAero + 1), Math.floor(yAero) + 1);
  var mergeJpg = merge4(jpg1, jpg2, jpg3, jpg4);
  return mergeJpg
  .then(function(image) {
    return scale(image, scaleFactorX, scaleFactorY);
  })
  .then(function(image) {
    var tileWidth = image.bitmap.width / 2;
    var tileHeight = image.bitmap.height / 2;
    var cropX1 = (xAero % 1) * tileWidth;
    var cropY1 = (yAero % 1) * tileHeight;
    return image.crop(Math.floor(cropX1), Math.floor(cropY1), osmTileWidth, osmTileWidth);
  })
  .then(function(image) {
    ctx.fillStyle = '#f0f';
    ctx.fillRect(0, 0, canvas.width, canvas.height);
    ctx.font = "35px Arial bold";
    ctx.fillStyle = '#000';
    ctx.fillText(xAero, 10, 50);
    ctx.fillText(yAero, 10, 100);

    var slowBuffer = canvas.toBuffer();
    var buffer = new Buffer(slowBuffer.length);
    slowBuffer.copy(buffer);
    return Jimp.read(buffer).then(function (text) {
      return image.mask(text, 0, 0);
    })
  })
  .then(getBuffer);
}

app.get('/:z/:y/:x.png', function (req, res) {
  var z = parseInt(req.params.z);
  var x = parseInt(req.params.x);
  var y = parseInt(req.params.y);
  console.log('Requesting ' + z + '/' + x + '/' + y)
  if(z == 13) {
    var base_offset_x = -3135;
    var base_offset_y = 55;
    z = 1;
    x = x + base_offset_x;
    y = y + base_offset_y;
  }
  else if(z == 20) {
    z = 6;
    getTileBytes(z, x, y, 1.286, 1.2899/*1.607, 1.6116*/).then(function(buf) {
      var img = buf;
      res.writeHead(200, {
        'Content-Type': Jimp.MIME_JPEG,
        'Content-Length': img.length
      });
      res.end(img);
    }).catch(function(e) {
      console.log(e.message);
      res.status(404).send('Not found');
    });
    return;
  }
  else {
    console.log(404);
    res.status(404).send('Not found');
    return;
  }
  var redir = getImageUrl(z, x, y);
  console.log(redir);
  res.redirect(redir);
});

app.listen(8082, function () {
  console.log('Odessa Aero app listening on port 8082!');
});