Fix leader length, add transparent pixels option

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### Change Log for Node-RED Worldmap
 
+ - v2.21.4 - fix speed leader length. Add transparentPixels option.
  - v2.21.3 - Add zoom to bounds action. Adjust map layers max zoom levels.
  - v2.21.2 - Expand ship nav to ship navigation.
  - v2.21.1 - Fix ui check callback to not use .

README.md

@@ -11,6 +11,7 @@ map web page for plotting "things" on.
 
 ### Updates
 
+- v2.21.4 - fix speed leader length. Add transparentPixels option..
 - v2.21.3 - Add zoom to bounds action. Adjust map layers max zoom levels.
 - v2.21.2 - Expand ship nav to ship navigation.
 - v2.21.1 - Fix ui check callback to not use .

package.json

@@ -1,6 +1,6 @@
 {
     "name": "node-red-contrib-web-worldmap",
-    "version": "2.21.3",
+    "version": "2.21.4",
     "description": "A Node-RED node to provide a web page of a world map for plotting things on.",
     "dependencies": {
         "@turf/bezier-spline": "~6.5.0",

worldmap/index.html

@@ -72,6 +72,7 @@
     <script src="leaflet/leaflet.latlng-graticule.js"></script>
     <script src="leaflet/VectorTileLayer.umd.min.js"></script>
     <script src="leaflet/Semicircle.js"></script>
+    <script src="leaflet/L.TileLayer.PixelFilter.js"></script>
     <script src="leaflet/dialog-polyfill.js"></script>
 
     <script src="images/emoji.js"></script>

worldmap/leaflet/L.TileLayer.PixelFilter.js

@@ -0,0 +1,152 @@
+/*
+ * L.TileLayer.PixelFilter
+ * https://github.com/greeninfo/L.TileLayer.PixelFilter
+ * http://greeninfo-network.github.io/L.TileLayer.PixelFilter/
+ */
+L.tileLayerPixelFilter = function (url, options) {
+    return new L.TileLayer.PixelFilter(url, options);
+}
+
+L.TileLayer.PixelFilter = L.TileLayer.extend({
+    // the constructor saves settings and throws a fit if settings are bad, as typical
+    // then adds the all-important 'tileload' event handler which basically "detects" an unmodified tile and performs the pxiel-swap
+    initialize: function (url, options) {
+        options = L.extend({}, L.TileLayer.prototype.options, {
+            matchRGBA: null,
+            missRGBA: null,
+            pixelCodes: [],
+            crossOrigin: 'Anonymous',  // per issue 15, this is how you do it in Leaflet 1.x
+        }, options);
+        L.TileLayer.prototype.initialize.call(this, url, options);
+        L.setOptions(this, options);
+
+        // go ahead and save our settings
+        this.setMatchRGBA(this.options.matchRGBA);
+        this.setMissRGBA(this.options.missRGBA);
+        this.setPixelCodes(this.options.pixelCodes);
+
+        // and add our tile-load event hook which triggers us to do the pixel-swap
+        this.on('tileload', function (event) {
+            this.applyFiltersToTile(event.tile);
+        });
+    },
+
+    // settings setters
+    setMatchRGBA: function (rgba) {
+        // save the setting
+        if (rgba !== null && (typeof rgba !== 'object' || typeof rgba.length !== 'number' || rgba.length !== 4) ) throw "L.TileLayer.PixelSwap expected matchRGBA to be RGBA [r,g,b,a] array or else null";
+        this.options.matchRGBA = rgba;
+
+        // force a redraw, which means new tiles, which mean new tileload events; the circle of life
+        this.redraw(true);
+    },
+    setMissRGBA: function (rgba) {
+        // save the setting
+        if (rgba !== null && (typeof rgba !== 'object' || typeof rgba.length !== 'number' || rgba.length !== 4) ) throw "L.TileLayer.PixelSwap expected missRGBA to be RGBA [r,g,b,a] array or else null";
+        this.options.missRGBA = rgba;
+
+        // force a redraw, which means new tiles, which mean new tileload events; the circle of life
+        this.redraw(true);
+    },
+    setPixelCodes: function (pixelcodes) {
+        // save the setting
+        if (typeof pixelcodes !== 'object' || typeof pixelcodes.length !== 'number') throw "L.TileLayer.PixelSwap expected pixelCodes to be a list of triplets: [ [r,g,b], [r,g,b], ... ]";
+        this.options.pixelCodes = pixelcodes;
+
+        // force a redraw, which means new tiles, which mean new tileload events; the circle of life
+        this.redraw(true);
+    },
+
+    // extend the _createTile function to add the .crossOrigin attribute, since loading tiles from a separate service is a pretty common need
+    // and the Canvas is paranoid about cross-domain image data. see issue #5
+    // this is really only for Leaflet 0.7; as of 1.0 L.TileLayer has a crossOrigin setting which we define as a layer option
+    _createTile: function () {
+        var tile = L.TileLayer.prototype._createTile.call(this);
+        tile.crossOrigin = "Anonymous";
+        return tile;
+    },
+
+    // the heavy lifting to do the pixel-swapping
+    // called upon 'tileload' and passed the IMG element
+    // tip: when the tile is saved back to the IMG element that counts as a tileload event too! thus an infinite loop, as wel as comparing the pixelCodes against already-replaced pixels!
+    //      so, we tag the already-swapped tiles so we know when to quit
+    // if the layer is redrawn, it's a new IMG element and that means it would not yet be tagged
+    applyFiltersToTile: function (imgelement) {
+        // already processed, see note above
+        if (imgelement.getAttribute('data-PixelFilterDone')) return;
+
+        // copy the image data onto a canvas for manipulation
+        var width  = imgelement.width;
+        var height = imgelement.height;
+        var canvas    = document.createElement("canvas");
+        canvas.width  = width;
+        canvas.height = height;
+        var context = canvas.getContext("2d");
+        context.drawImage(imgelement, 0, 0);
+
+        // create our target imagedata
+        var output = context.createImageData(width, height);
+
+        // extract out our RGBA trios into separate numbers, so we don't have to use rgba[i] a zillion times
+        var matchRGBA = this.options.matchRGBA, missRGBA = this.options.missRGBA;
+        if (matchRGBA !== null) {
+            var match_r = matchRGBA[0], match_g = matchRGBA[1], match_b = matchRGBA[2], match_a = matchRGBA[3];
+        }
+        if (missRGBA !== null) {
+            var miss_r = missRGBA[0], miss_g = missRGBA[1], miss_b = missRGBA[2], miss_a = missRGBA[3];
+        }
+
+        // go over our pixel-code list and generate the list of integers that we'll use for RGB matching
+        // 1000000*R + 1000*G + B = 123123123 which is an integer, and finding an integer inside an array is a lot faster than finding an array inside an array
+        var pixelcodes = [];
+        for (var i=0, l=this.options.pixelCodes.length; i<l; i++) {
+            var value = 1000000 * this.options.pixelCodes[i][0] + 1000 * this.options.pixelCodes[i][1] + this.options.pixelCodes[i][2];
+            pixelcodes.push(value);
+        }
+
+        // iterate over the pixels (each one is 4 bytes, RGBA)
+        // and see if they are on our list (recall the "addition" thing so we're comparing integers in an array for performance)
+        // per issue #5 catch a failure here, which is likely a cross-domain problem
+        try {
+            var pixels = context.getImageData(0, 0, width, height).data;
+        } catch(e) {
+            throw "L.TileLayer.PixelFilter getImageData() failed. Likely a cross-domain issue?";
+        }
+        for(var i = 0, n = pixels.length; i < n; i += 4) {
+            var r = pixels[i  ];
+            var g = pixels[i+1];
+            var b = pixels[i+2];
+            var a = pixels[i+3];
+
+            // bail condition: if the alpha is 0 then it's already transparent, likely nodata, and we should skip it
+            if (a == 0) {
+                output.data[i  ] = 255;
+                output.data[i+1] = 255;
+                output.data[i+2] = 255;
+                output.data[i+3] = 0;
+                continue;
+            }
+
+            // default to matching, so that if we are not in fact filtering by code it's an automatic hit
+            // number matching trick: 1000000*R + 1000*G + 1*B = 123,123,123 a simple number that either is or isn't on the list
+            var match = true;
+            if (pixelcodes.length) {
+                var sum = 1000000 * r + 1000 * g + b;
+                if (-1 === pixelcodes.indexOf(sum)) match = false;
+            }
+
+            // did it match? either way we push a R, a G, and a B onto the image blob
+            // if the target RGBA is a null, then we push exactly the same RGBA as we found in the source pixel
+            output.data[i  ] = match ? (matchRGBA===null ? r : match_r) : (missRGBA===null ? r : miss_r);
+            output.data[i+1] = match ? (matchRGBA===null ? g : match_g) : (missRGBA===null ? g : miss_g);
+            output.data[i+2] = match ? (matchRGBA===null ? b : match_b) : (missRGBA===null ? b : miss_b);
+            output.data[i+3] = match ? (matchRGBA===null ? a : match_a) : (missRGBA===null ? a : miss_a);
+        }
+
+        // write the image back to the canvas, and assign its base64 back into the on-screen tile to visualize the change
+        // tag the tile as having already been updated, so we don't process a 'load' event again and re-process a tile that surely won't match any target RGB codes, in an infinite loop!
+        context.putImageData(output, 0, 0);
+        imgelement.setAttribute('data-PixelFilterDone', true);
+        imgelement.src = canvas.toDataURL();
+    }
+});

worldmap/worldmap.js

@@ -1983,7 +1983,7 @@ function setMarker(data) {
     else if (data.heading !== undefined) { track = data.heading; }
     else if (data.bearing !== undefined) { track = data.bearing; }
     if (track != undefined) {  // if there is a heading
-        if (data.speed != null && !data.length) {  // and a speed - lets convert to a leader length
+        if (data.speed != null && data.length === undefined) {  // and a speed - lets convert to a leader length
             data.length = parseFloat(data.speed || "0") * 60;
             var re1 = new RegExp('kn|knot|kt','i');
             var re2 = new RegExp('kph|kmh','i');
@@ -1992,7 +1992,7 @@ function setMarker(data) {
             else if ( re2.test(""+data.speed) ) { data.length = data.length * 0.44704; }
             else if ( re3.test(""+data.speed) ) { data.length = data.length * 0.277778; }
         }
-        if (data.length != null) {
+        if (data.length !== undefined) {
             if (polygons[data.name] != null && !polygons[data.name].hasOwnProperty("_layers")) {
                 map.removeLayer(polygons[data.name]);
             }
@@ -2452,6 +2452,11 @@ function doCommand(cmd) {
         else if (cmd.map.url.slice(-4).toLowerCase() === ".pbf") {
             overlays[cmd.map.overlay] = VectorTileLayer(cmd.map.url, cmd.map.opt);
         }
+        else if (cmd.map.hasOwnProperty("transparentPixels")) {
+            cmd.map.opt.pixelCodes =  cmd.map.transparentPixels;
+            cmd.map.opt.matchRGBA = [ 0,0,0,0 ];
+            overlays[cmd.map.overlay] = L.tileLayerPixelFilter(cmd.map.url, cmd.map.opt);
+        }
         else {
             overlays[cmd.map.overlay] = L.tileLayer(cmd.map.url, cmd.map.opt);
         }

worldmap/worldmaphead.html

@@ -42,6 +42,7 @@
 <script src="leaflet/Leaflet.Coordinates.js"></script>
 <script src="leaflet/leaflet.latlng-graticule.js"></script>
 <script src="leaflet/Semicircle.js"></script>
+<script src="leaflet/L.TileLayer.PixelFilter.js"></script>
 <script src="leaflet/dialog-polyfill.js"></script>
 
 <script src="images/emoji.js"></script>