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Diffstat (limited to 'misc/openlayers/examples/offline-storage.js')
| -rw-r--r-- | misc/openlayers/examples/offline-storage.js | 199 |
1 files changed, 0 insertions, 199 deletions
diff --git a/misc/openlayers/examples/offline-storage.js b/misc/openlayers/examples/offline-storage.js deleted file mode 100644 index e0b5929..0000000 --- a/misc/openlayers/examples/offline-storage.js +++ /dev/null @@ -1,199 +0,0 @@ -// 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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