kmap-ui/src/components/ol/source/DFCI.js

A components of zmap base on vue2.X

/*	Copyright (c) 2018 Jean-Marc VIGLINO, 
	released under the CeCILL-B license (French BSD license)
	(http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt).
*/

import ol_ext_inherits from '../util/ext'
import ol_geom_Polygon from 'ol/geom/Polygon'
import ol_Feature from 'ol/Feature'
import ol_source_Vector from 'ol/source/Vector'
import {ol_coordinate_toDFCI} from '../geom/DFCI'
import {transformExtent as ol_proj_transformExtent} from 'ol/proj'
import {register as ol_proj_proj4_register} from 'ol/proj/proj4.js';
import proj4 from 'proj4';

/** DFCI source: a source to display the French DFCI grid on a map
 * @see http://ccffpeynier.free.fr/Files/dfci.pdf
 * @constructor ol_source_DFCI
 * @extends {ol/source/Vector}
 * @param {any} options Vector source options
 *  @param {Array<Number>} resolutions a list of resolution to change the drawing level, default [1000,100,20]
 */
var ol_source_DFCI = function(options) {
	options = options || {};

	options.loader = this._calcGrid;
  options.strategy =  function(extent, resolution) {
    if (this.resolution && this.resolution != resolution){
      this.clear();
      this.refresh();
    }
    return [extent];
  }
  
  this._bbox = [[0,1600000],[11*100000, 1600000+10*100000]];
  ol_source_Vector.call (this, options);

  this.set('resolutions', options.resolutions || [1000,100,20]);

  // Add Lambert IIe proj 
  if (!proj4.defs["EPSG:27572"]) proj4.defs("EPSG:27572","+proj=lcc +lat_1=46.8 +lat_0=46.8 +lon_0=0 +k_0=0.99987742 +x_0=600000 +y_0=2200000 +a=6378249.2 +b=6356515 +towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs");
  ol_proj_proj4_register(proj4);
};
ol_ext_inherits(ol_source_DFCI, ol_source_Vector);


/** Cacluate grid according extent/resolution
 */
ol_source_DFCI.prototype._calcGrid = function (extent, resolution, projection) {
  // Show step 0
  var f, ext, res = this.get('resolutions');
  if (resolution > (res[0] || 1000)) {
    if (this.resolution != resolution) {
      if (!this._features0) {
        ext = [this._bbox[0][0], this._bbox[0][1],this._bbox[1][0], this._bbox[1][1]];
        this._features0 = this._getFeatures(0, ext, projection);
      }
      this.addFeatures(this._features0);
    }
  }
  else if (resolution > (res[1] || 100)) {
    this.clear();
    ext = ol_proj_transformExtent(extent, projection, 'EPSG:27572');
    f = this._getFeatures(1, ext, projection)
    this.addFeatures(f);
  }
  else if (resolution > (res[2] || 0)) {
    this.clear();
    ext = ol_proj_transformExtent(extent, projection, 'EPSG:27572');
    f = this._getFeatures(2, ext, projection)
    this.addFeatures(f);
  }
  else {
    this.clear();
    ext = ol_proj_transformExtent(extent, projection, 'EPSG:27572');
    f = this._getFeatures(3, ext, projection)
    this.addFeatures(f);
  }

  // reset load
  this.resolution = resolution;
};

/**
 * Get middle point
 * @private
 */
ol_source_DFCI.prototype._midPt = function(p1,p2) {
  return [(p1[0]+p2[0])/2, (p1[1]+p2[1])/2];
};

/**
 * Get feature with geom
 * @private
 */
ol_source_DFCI.prototype._trFeature = function(geom, id, level, projection) {
  var g  = new ol_geom_Polygon([geom]);
  var f = new ol_Feature(g.transform('EPSG:27572', projection));
  f.set('id', id);
  f.set('level', level);
  return f;
};

/** Get features
 * 
 */
ol_source_DFCI.prototype._getFeatures = function (level, extent, projection) {
  var features = [];
  var i;
  var step = 100000;
  if (level>0) step /= 5;
  if (level>1) step /= 10;
  var p0 = [
    Math.max(this._bbox[0][0], Math.floor(extent[0]/step)*step), 
    Math.max(this._bbox[0][1], Math.floor(extent[1]/step)*step)
  ];
  var p1 = [
    Math.min(this._bbox[1][0]+99999, Math.floor(extent[2]/step)*step), 
    Math.min(this._bbox[1][1]+99999, Math.floor(extent[3]/step)*step)
  ];
  for (var x=p0[0]; x<=p1[0]; x += step) {
    for (var y=p0[1]; y<=p1[1]; y += step) {
      var p, geom = [ [x,y], [x+step, y], [x+step, y+step], [x , y+step], [x,y]];
      if (level>2) {
        var m = this._midPt(geom[0],geom[2]);
        // .5
        var g = [];
        for (i=0; i<geom.length; i++) {
          g.push(this._midPt(geom[i],m))
        }
        features.push(this._trFeature(g, ol_coordinate_toDFCI([x,y], 2)+'.5', level, projection));
        // .1 > .4
        for (i=0; i<4; i++) {
          g = [];
          g.push(geom[i]);
          g.push(this._midPt(geom[i],geom[(i+1)%4]));
          g.push(this._midPt(m,g[1]));
          g.push(this._midPt(m,geom[i]));
          p = this._midPt(geom[i],geom[(i+3)%4]);
          g.push(this._midPt(m,p));
          g.push(p);
          g.push(geom[i]);
          features.push(this._trFeature(g, ol_coordinate_toDFCI([x,y], 2)+'.'+(4-i), level, projection));
        }
      } else {
        features.push(this._trFeature(geom, ol_coordinate_toDFCI([x,y], level), level, projection));
      }
    }
  }
  return features
};

export default ol_source_DFCI