Adding jquery, flot and openlayers to be included with the GEM.v0.0.4

1 files changed, 199 insertions, 0 deletions

diff --git a/misc/openlayers/examples/offline-storage.js b/misc/openlayers/examples/offline-storage.js
new file mode 100644
index 0000000..e0b5929
--- /dev/null
+++ b/misc/openlayers/examples/offline-storage.js
@@ -0,0 +1,199 @@
+// Use proxy to get same origin URLs for tiles that don't support CORS.
+OpenLayers.ProxyHost = "proxy.cgi?url=";
+
+var map, cacheWrite, cacheRead1, cacheRead2;
+
+function init() {
+    map = new OpenLayers.Map({
+        div: "map",
+        projection: "EPSG:900913",
+        layers: [
+            new OpenLayers.Layer.OSM("OpenStreetMap (CORS)", null, {
+                eventListeners: {
+                    tileloaded: updateStatus,
+                    loadend: detect
+                }
+            }),
+            new OpenLayers.Layer.WMS("OSGeo (same origin - proxied)", "http://vmap0.tiles.osgeo.org/wms/vmap0", {
+                layers: "basic"
+            }, {
+                eventListeners: {
+                    tileloaded: updateStatus
+                }
+            })
+        ],
+        center: [0, 0],
+        zoom: 1
+    });
+    // try cache before loading from remote resource
+    cacheRead1 = new OpenLayers.Control.CacheRead({
+        eventListeners: {
+            activate: function() {
+                cacheRead2.deactivate();
+            }
+        }
+    });
+    // try loading from remote resource and fall back to cache
+    cacheRead2 = new OpenLayers.Control.CacheRead({
+        autoActivate: false,
+        fetchEvent: "tileerror",
+        eventListeners: {
+            activate: function() {
+                cacheRead1.deactivate();
+            }
+        }
+    });
+    cacheWrite = new OpenLayers.Control.CacheWrite({
+        imageFormat: "image/jpeg",
+        eventListeners: {
+            cachefull: function() {
+                if (seeding) {
+                    stopSeeding();
+                }
+                status.innerHTML = "Cache full.";
+            }
+        }
+    });
+    var layerSwitcher = new OpenLayers.Control.LayerSwitcher();
+    map.addControls([cacheRead1, cacheRead2, cacheWrite, layerSwitcher]);
+    layerSwitcher.maximizeControl();
+
+
+    
+    // add UI and behavior
+    var status = document.getElementById("status"),
+        hits = document.getElementById("hits"),
+        cacheHits = 0,
+        seeding = false;
+    var read = document.getElementById("read");
+    read.checked = true;
+    read.onclick = toggleRead;
+    var write = document.getElementById("write");
+    write.checked = false;
+    write.onclick = toggleWrite;
+    document.getElementById("clear").onclick = clearCache;
+    var tileloadstart = document.getElementById("tileloadstart");
+    tileloadstart.checked = "checked";
+    tileloadstart.onclick = setType;
+    document.getElementById("tileerror").onclick = setType;
+    document.getElementById("seed").onclick = startSeeding;
+    
+    // detect what the browser supports
+    function detect(evt) {
+        // detection is only done once, so we remove the listener.
+        evt.object.events.unregister("loadend", null, detect);
+        var tile = map.baseLayer.grid[0][0];
+        try {
+            var canvasContext = tile.getCanvasContext();
+            if (canvasContext) {
+                // will throw an exception if CORS image requests are not supported
+                canvasContext.canvas.toDataURL();
+            } else {
+                status.innerHTML = "Canvas not supported. Try a different browser.";
+            }
+        } catch(e) {
+            // we remove the OSM layer if CORS image requests are not supported.
+            map.setBaseLayer(map.layers[1]);
+            evt.object.destroy();
+            layerSwitcher.destroy();
+        }
+    }
+
+    // update the number of cache hits and detect missing CORS support
+    function updateStatus(evt) {
+        if (window.localStorage) {
+            status.innerHTML = localStorage.length + " entries in cache.";
+        } else {
+            status.innerHTML = "Local storage not supported. Try a different browser.";
+        }
+        if (evt && evt.tile.url.substr(0, 5) === "data:") {
+            cacheHits++;
+        }
+        hits.innerHTML = cacheHits + " cache hits.";
+    }
+    
+    // turn the cacheRead controls on and off
+    function toggleRead() {
+        if (!this.checked) {
+            cacheRead1.deactivate();
+            cacheRead2.deactivate();
+        } else {
+            setType();
+        }
+    }
+    
+    // turn the cacheWrite control on and off
+    function toggleWrite() {
+        cacheWrite[cacheWrite.active ? "deactivate" : "activate"]();
+    }
+    
+    // clear all tiles from the cache
+    function clearCache() {
+        OpenLayers.Control.CacheWrite.clearCache();
+        updateStatus();
+    }
+    
+    // activate the cacheRead control that matches the desired fetch strategy
+    function setType() {
+        if (tileloadstart.checked) {
+            cacheRead1.activate();
+        } else {
+            cacheRead2.activate();
+        }
+    }
+    
+    // start seeding the cache
+    function startSeeding() {
+        var layer = map.baseLayer,
+            zoom = map.getZoom();
+        seeding = {
+            zoom: zoom,
+            extent: map.getExtent(),
+            center: map.getCenter(),
+            cacheWriteActive: cacheWrite.active,
+            buffer: layer.buffer,
+            layer: layer
+        };
+        // make sure the next setCenter triggers a load
+        map.zoomTo(zoom === layer.numZoomLevels-1 ? zoom - 1 : zoom + 1);
+        // turn on cache writing
+        cacheWrite.activate();
+        // turn off cache reading
+        cacheRead1.deactivate();
+        cacheRead2.deactivate();
+        
+        layer.events.register("loadend", null, seed);
+        
+        // start seeding
+        map.setCenter(seeding.center, zoom);
+    }
+    
+    // seed a zoom level based on the extent at the time startSeeding was called
+    function seed() {
+        var layer = seeding.layer;
+        var tileWidth = layer.tileSize.w;
+        var nextZoom = map.getZoom() + 1;
+        var extentWidth = seeding.extent.getWidth() / map.getResolutionForZoom(nextZoom);
+        // adjust the layer's buffer size so we don't have to pan
+        layer.buffer = Math.ceil((extentWidth / tileWidth - map.getSize().w / tileWidth) / 2);
+        map.zoomIn();
+        if (nextZoom === layer.numZoomLevels-1) {
+            stopSeeding();
+        }
+    }
+    
+    // stop seeding (when done or when cache is full)
+    function stopSeeding() {
+        // we're done - restore previous settings
+        seeding.layer.events.unregister("loadend", null, seed);
+        seeding.layer.buffer = seeding.buffer;
+        map.setCenter(seeding.center, seeding.zoom);
+        if (!seeding.cacheWriteActive) {
+            cacheWrite.deactivate();
+        }
+        if (read.checked) {
+            setType();
+        }
+        seeding = false;
+    }
+}
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