ffrgb / meshviewer

  function (L, rbush, helper) {

    'use strict';

    var labelLocations = [['left', 'middle', 0 / 8],

      ['center', 'top', 6 / 8],

      ['right', 'middle', 4 / 8],

      ['left', 'top', 7 / 8],

      ['left', 'ideographic', 1 / 8],

      ['right', 'top', 5 / 8],

      ['center', 'ideographic', 2 / 8],

      ['right', 'ideographic', 3 / 8]];

    var labelShadow;

    var bodyStyle = { fontFamily: 'sans-serif' };

    var nodeRadius = 4;

    var cFont = document.createElement('canvas').getContext('2d');

    function measureText(font, text) {

      cFont.font = font;

      return cFont.measureText(text);

    }

    function prepareLabel(fillStyle, fontSize, offset, stroke) {

      return function (d) {

        var font = fontSize + 'px ' + bodyStyle.fontFamily;

        return {

          position: L.latLng(d.nodeinfo.location.latitude, d.nodeinfo.location.longitude),

          label: d.nodeinfo.hostname,

          offset: offset,

          fillStyle: fillStyle,

          height: fontSize * 1.2,

          font: font,

          stroke: stroke,

          width: measureText(font, d.nodeinfo.hostname).width

        };

      };

    }

    function calcOffset(offset, loc) {

      return [offset * Math.cos(loc[2] * 2 * Math.PI),

        -offset * Math.sin(loc[2] * 2 * Math.PI)];

    }

    function labelRect(p, offset, anchor, label, minZoom, maxZoom, z) {

      var margin = 1 + 1.41 * (1 - (z - minZoom) / (maxZoom - minZoom));

      var width = label.width * margin;

      var height = label.height * margin;

      var dx = {

        left: 0,

        right: -width,

        center: -width / 2

      };

      var dy = {

        top: 0,

        ideographic: -height,

        middle: -height / 2

      };

      var x = p.x + offset[0] + dx[anchor[0]];

      var y = p.y + offset[1] + dy[anchor[1]];

      return { minX: x, minY: y, maxX: x + width, maxY: y + height };

    }

    return L.GridLayer.extend({

      onAdd: function (map) {

        L.GridLayer.prototype.onAdd.call(this, map);

        if (this.data) {

          this.prepareLabels();

        }

      },

      setData: function (d) {

        this.data = d;

        this.updateLayer();

      },

      updateLayer: function () {

        if (this._map) {

          this.prepareLabels();

        }

      },

      prepareLabels: function () {

        var d = this.data;

        // label:

        // - position (WGS84 coords)

        // - offset (2D vector in pixels)

        // - anchor (tuple, textAlignment, textBaseline)

        // - minZoom (inclusive)

        // - label (string)

        // - color (string)

        var labelsOnline = d.online.map(prepareLabel(null, 11, 8, true));

        var labelsOffline = d.offline.map(prepareLabel('rgba(212, 62, 42, 0.9)', 9, 5, false));

        var labelsNew = d.new.map(prepareLabel('rgba(48, 99, 20, 0.9)', 11, 8, true));

        var labelsLost = d.lost.map(prepareLabel('rgba(212, 62, 42, 0.9)', 11, 8, true));

        var labels = []

          .concat(labelsNew)

          .concat(labelsLost)

          .concat(labelsOnline)

          .concat(labelsOffline);

        var minZoom = this.options.minZoom;

        var maxZoom = this.options.maxZoom;

        var trees = [];

        var map = this._map;

        function nodeToRect(z) {

          return function (n) {

            var p = map.project(n.position, z);

            return { minX: p.x - nodeRadius, minY: p.y - nodeRadius, maxX: p.x + nodeRadius, maxY: p.y + nodeRadius };

          };

        }

        for (var z = minZoom; z <= maxZoom; z++) {

          trees[z] = rbush(9);

          trees[z].load(labels.map(nodeToRect(z)));

        }

        labels = labels.map(function (n) {

          var best = labelLocations.map(function (loc) {

            var offset = calcOffset(n.offset, loc);

            var i;

            for (i = maxZoom; i >= minZoom; i--) {

              var p = map.project(n.position, i);

              var rect = labelRect(p, offset, loc, n, minZoom, maxZoom, i);

              var candidates = trees[i].search(rect);

              if (candidates.length > 0) {

                break;

              }

            }

            return { loc: loc, z: i + 1 };

          }).filter(function (k) {

            return k.z <= maxZoom;

          }).sort(function (a, b) {

            return a.z - b.z;

          })[0];

          if (best !== undefined) {

            n.offset = calcOffset(n.offset, best.loc);

            n.minZoom = best.z;

            n.anchor = best.loc;

            for (var i = maxZoom; i >= best.z; i--) {

              var p = map.project(n.position, i);

              var rect = labelRect(p, n.offset, best.loc, n, minZoom, maxZoom, i);

              trees[i].insert(rect);

            }

            return n;

          }

          return undefined;

        }).filter(function (n) {

          return n !== undefined;

        });

        this.margin = 16;

        if (labels.length > 0) {

          this.margin += labels.map(function (n) {

            return n.width;

          }).sort().reverse()[0];

        }

        this.labels = rbush(9);

        this.labels.load(labels.map(mapRTree));

        this.redraw();

      },

      createTile: function (tilePoint) {

        var tile = L.DomUtil.create('canvas', 'leaflet-tile');

        var tileSize = this.options.tileSize;

        tile.width = tileSize;

        tile.height = tileSize;

        if (!this.labels) {

          return tile;

        }

        var s = tilePoint.multiplyBy(tileSize);

        var map = this._map;

        bodyStyle = window.getComputedStyle(document.querySelector('body'));

        labelShadow = bodyStyle.backgroundColor.replace(/rgb/i, 'rgba').replace(/\)/i, ',0.7)');

        function projectNodes(d) {

          var p = map.project(d.label.position);

          p.x -= s.x;

          p.y -= s.y;

          return { p: p, label: d.label };

        }

        var bbox = helper.getTileBBox(s, map, tileSize, this.margin);

        var labels = this.labels.search(bbox).map(projectNodes);

        var ctx = tile.getContext('2d');

        ctx.lineWidth = 5;

        ctx.strokeStyle = labelShadow;

        ctx.miterLimit = 2;

        function drawLabel(d) {

          ctx.font = d.label.font;

          ctx.textAlign = d.label.anchor[0];

          ctx.textBaseline = d.label.anchor[1];

          ctx.fillStyle = d.label.fillStyle === null ? bodyStyle.color : d.label.fillStyle;

          if (d.label.stroke) {

            ctx.strokeText(d.label.label, d.p.x + d.label.offset[0], d.p.y + d.label.offset[1]);

          }

          ctx.fillText(d.label.label, d.p.x + d.label.offset[0], d.p.y + d.label.offset[1]);

        }

        labels.filter(function (d) {

          return tilePoint.z >= d.label.minZoom;

        }).forEach(drawLabel);

        return tile;

      }

    });

  });