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Merge pull request #702 from ahocevar/smart-queue

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New tile image cache and tile queue improvements. r=@bartvde,@elemoine
This commit is contained in:
ahocevar
2013-01-07 06:38:07 -08:00
parent 9adbf431ca 4a3651b7da
commit 18d548f979
18 changed files with 656 additions and 237 deletions
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lib/OpenLayers.js
+1
View File
@@ -400,6 +400,7 @@
"OpenLayers/Lang.js",
"OpenLayers/Lang/en.js",
"OpenLayers/Spherical.js",
"OpenLayers/TileManager.js",
"OpenLayers/WPSClient.js",
"OpenLayers/WPSProcess.js"
]; // etc.
lib/OpenLayers/Layer/Bing.js
+7 -12
View File
@@ -197,20 +197,12 @@ OpenLayers.Layer.Bing = OpenLayers.Class(OpenLayers.Layer.XYZ, {
res.zoomMax + 1 - res.zoomMin, this.numZoomLevels
)
}, true);
if (!this.isBaseLayer) {
this.redraw();
}
this.updateAttribution();
},
/**
* Method: drawTileFromQueue
* Draws the first tile from the tileQueue, and unqueues that tile
*/
drawTileFromQueue: function() {
// don't start working on the queue before we have a url from initLayer
if (this.url) {
OpenLayers.Layer.XYZ.prototype.drawTileFromQueue.apply(this, arguments);
}
},
/**
* Method: getURL
*
@@ -218,6 +210,9 @@ OpenLayers.Layer.Bing = OpenLayers.Class(OpenLayers.Layer.XYZ, {
* bounds - {<OpenLayers.Bounds>}
*/
getURL: function(bounds) {
if (!this.url) {
return;
}
var xyz = this.getXYZ(bounds), x = xyz.x, y = xyz.y, z = xyz.z;
var quadDigits = [];
for (var i = z; i > 0; --i) {
lib/OpenLayers/Layer/Grid.js
+14 -122
View File
@@ -113,14 +113,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
*/
numLoadingTiles: 0,
/**
* APIProperty: tileLoadingDelay
* {Integer} Number of milliseconds before we shift and load
* tiles when panning. Ignored if <OpenLayers.Animation.isNative> is
* true. Default is 85.
*/
tileLoadingDelay: 85,
/**
* Property: serverResolutions
* {Array(Number}} This property is documented in subclasses as
@@ -128,32 +120,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
*/
serverResolutions: null,
/**
* Property: moveTimerId
* {Number} The id of the <deferMoveGriddedTiles> timer.
*/
moveTimerId: null,
/**
* Property: deferMoveGriddedTiles
* {Function} A function that defers execution of <moveGriddedTiles> by
* <tileLoadingDelay>. If <OpenLayers.Animation.isNative> is true, this
* is null and unused.
*/
deferMoveGriddedTiles: null,
/**
* Property: tileQueueId
* {Number} The id of the <drawTileFromQueue> animation.
*/
tileQueueId: null,
/**
* Property: tileQueue
* {Array(<OpenLayers.Tile>)} Tiles queued for drawing.
*/
tileQueue: null,
/**
* Property: loading
* {Boolean} Indicates if tiles are being loaded.
@@ -240,7 +206,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* should not be zero.
*/
className: null,
/**
* Register a listener for a particular event with the following syntax:
* (code)
@@ -255,6 +221,9 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* element - {DOMElement} A reference to layer.events.element.
*
* Supported event types:
* addtile - Triggered when a tile is added to this layer. Listeners receive
* an object as first argument, which has a tile property that
* references the tile that has been added.
* tileloadstart - Triggered when a tile starts loading. Listeners receive
* an object as first argument, which has a tile property that
* references the tile that starts loading.
@@ -269,6 +238,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* still hidden) if a tile failed to load. Listeners receive an object
* as first argument, which has a tile property that references the
* tile that could not be loaded.
* retile - Triggered when the layer recreates its tile grid.
*/
/**
@@ -308,18 +278,10 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
OpenLayers.Layer.HTTPRequest.prototype.initialize.apply(this,
arguments);
this.grid = [];
this.tileQueue = [];
this._removeBackBuffer = OpenLayers.Function.bind(this.removeBackBuffer, this);
this.initProperties();
if (!OpenLayers.Animation.isNative) {
this.deferMoveGriddedTiles = OpenLayers.Function.bind(function() {
this.moveGriddedTiles(true);
this.moveTimerId = null;
}, this);
}
this.rowSign = this.tileOriginCorner.substr(0, 1) === "t" ? 1 : -1;
},
@@ -358,15 +320,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* map - {<OpenLayers.Map>} The map.
*/
removeMap: function(map) {
if (this.moveTimerId !== null) {
window.clearTimeout(this.moveTimerId);
this.moveTimerId = null;
}
this.clearTileQueue();
if(this.backBufferTimerId !== null) {
window.clearTimeout(this.backBufferTimerId);
this.backBufferTimerId = null;
}
this.removeBackBuffer();
},
/**
@@ -388,7 +342,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* destroy() on each of them to kill circular references
*/
clearGrid:function() {
this.clearTileQueue();
if (this.grid) {
for(var iRow=0, len=this.grid.length; iRow<len; iRow++) {
var row = this.grid[iRow];
@@ -456,13 +409,10 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
// we do not want to copy reference to grid, so we make a new array
obj.grid = [];
obj.gridResolution = null;
// same for backbuffer and tile queue
// same for backbuffer
obj.backBuffer = null;
obj.backBufferTimerId = null;
obj.tileQueue = [];
obj.tileQueueId = null;
obj.loading = false;
obj.moveTimerId = null;
return obj;
},
@@ -608,50 +558,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
return data;
},
/**
* Method: queueTileDraw
* Adds a tile to the animation queue that will draw it.
*
* Parameters:
* evt - {Object} Listener argument of the tile's beforedraw event
*/
queueTileDraw: function(evt) {
var tile = evt.object;
if (!~OpenLayers.Util.indexOf(this.tileQueue, tile)) {
// queue only if not in queue already
this.tileQueue.push(tile);
}
if (!this.tileQueueId) {
this.tileQueueId = OpenLayers.Animation.start(
OpenLayers.Function.bind(this.drawTileFromQueue, this),
null, this.div
);
}
return false;
},
/**
* Method: drawTileFromQueue
* Draws the first tile from the tileQueue, and unqueues that tile
*/
drawTileFromQueue: function() {
if (this.tileQueue.length === 0) {
this.clearTileQueue();
} else {
this.tileQueue.shift().draw(true);
}
},
/**
* Method: clearTileQueue
* Clears the animation queue
*/
clearTileQueue: function() {
OpenLayers.Animation.stop(this.tileQueueId);
this.tileQueueId = null;
this.tileQueue = [];
},
/**
* Method: destroyTile
*
@@ -881,7 +787,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* bounds - {<OpenLayers.Bounds>}
*/
initSingleTile: function(bounds) {
this.clearTileQueue();
this.events.triggerEvent("retile");
//determine new tile bounds
var center = bounds.getCenterLonLat();
@@ -1014,7 +920,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* bounds - {<OpenLayers.Bounds>}
*/
initGriddedTiles:function(bounds) {
this.clearTileQueue();
this.events.triggerEvent("retile");
// work out mininum number of rows and columns; this is the number of
// tiles required to cover the viewport plus at least one for panning
@@ -1093,8 +999,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
//shave off exceess rows and colums
this.removeExcessTiles(rowidx, colidx);
var resolution = this.getServerResolution(),
immediately = resolution === this.gridResolution;
var resolution = this.getServerResolution();
// store the resolution of the grid
this.gridResolution = resolution;
@@ -1103,7 +1008,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
return a.distance - b.distance;
});
for (var i=0, ii=tileData.length; i<ii; ++i) {
tileData[i].tile.draw(immediately);
tileData[i].tile.draw();
}
},
@@ -1134,7 +1039,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
var tile = new this.tileClass(
this, position, bounds, null, this.tileSize, this.tileOptions
);
tile.events.register("beforedraw", this, this.queueTileDraw);
this.events.triggerEvent("addtile", {tile: tile});
return tile;
},
@@ -1165,7 +1070,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
aborted: evt.type === "unload"
});
//if that was the last tile, then trigger a 'loadend' on the layer
if (this.tileQueue.length === 0 && this.numLoadingTiles === 0) {
if (this.numLoadingTiles === 0) {
this.loading = false;
this.events.triggerEvent("loadend");
if(this.backBuffer) {
@@ -1218,21 +1123,8 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
/**
* Method: moveGriddedTiles
*
* Parameter:
* deferred - {Boolean} true if this is a deferred call that should not
* be delayed.
*/
moveGriddedTiles: function(deferred) {
if (!deferred && !OpenLayers.Animation.isNative) {
if (this.moveTimerId != null) {
window.clearTimeout(this.moveTimerId);
}
this.moveTimerId = window.setTimeout(
this.deferMoveGriddedTiles, this.tileLoadingDelay
);
return;
}
moveGriddedTiles: function() {
var buffer = this.buffer + 1;
while(true) {
var tlTile = this.grid[0][0];
lib/OpenLayers/Map.js
+17
View File
@@ -370,6 +370,14 @@ OpenLayers.Map = OpenLayers.Class({
* property at the time the control is added to the map.
*/
displayProjection: null,
/**
* APIProperty: tileManager
* {<OpenLayers.TileManager>} If configured at construction time, the map
* will use the TileManager to queue image requests and to cache tile image
* elements.
*/
tileManager: null,
/**
* APIProperty: fallThrough
@@ -579,6 +587,10 @@ OpenLayers.Map = OpenLayers.Class({
this, this.viewPortDiv, null, this.fallThrough,
{includeXY: true}
);
if (this.tileManager) {
this.tileManager.addMap(this);
}
// the layerContainerDiv is the one that holds all the layers
id = this.id + "_OpenLayers_Container";
@@ -778,6 +790,11 @@ OpenLayers.Map = OpenLayers.Class({
this.viewPortDiv.parentNode.removeChild(this.viewPortDiv);
}
this.viewPortDiv = null;
if (this.tileManager) {
this.tileManager.removeMap(this);
this.tileManager = null;
}
if(this.eventListeners) {
this.events.un(this.eventListeners);
lib/OpenLayers/Tile.js
+10 -9
View File
@@ -193,22 +193,23 @@ OpenLayers.Tile = OpenLayers.Class({
* is to call <clear> and return the result from <shouldDraw>.
*
* Parameters:
* immediately - {Boolean} When e.g. drawing was aborted by returning false
* from a *beforedraw* listener, the queue manager needs to pass true,
* so the tile will not be cleared and immediately be drawn. Otherwise,
* the tile will be cleared and a *beforedraw* event will be fired.
* force - {Boolean} If true, the tile will not be cleared and no beforedraw
* event will be fired. This is used for drawing tiles asynchronously
* after drawing has been cancelled by returning false from a beforedraw
* listener.
*
* Returns:
* {Boolean} Whether or not the tile should actually be drawn.
* {Boolean} Whether or not the tile should actually be drawn. Returns null
* if a beforedraw listener returned false.
*/
draw: function(immediately) {
if (!immediately) {
draw: function(force) {
if (!force) {
//clear tile's contents and mark as not drawn
this.clear();
}
var draw = this.shouldDraw();
if (draw && !immediately) {
draw = this.events.triggerEvent("beforedraw") !== false;
if (draw && !force && this.events.triggerEvent("beforedraw") === false) {
draw = null;
}
return draw;
},
lib/OpenLayers/Tile/Image.js
+55 -12
View File
@@ -20,6 +20,23 @@
*/
OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
/**
* APIProperty: events
* {<OpenLayers.Events>} An events object that handles all
* events on the tile.
*
* Register a listener for a particular event with the following syntax:
* (code)
* tile.events.register(type, obj, listener);
* (end)
*
* Supported event types (in addition to the <OpenLayers.Tile> events):
* beforeload - Triggered before an image is prepared for loading, when the
* url for the image is known already. Listeners may call <setImage> on
* the tile instance. If they do so, that image will be used and no new
* one will be created.
*/
/**
* APIProperty: url
* {String} The URL of the image being requested. No default. Filled in by
@@ -146,11 +163,12 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
* Check that a tile should be drawn, and draw it.
*
* Returns:
* {Boolean} Was a tile drawn?
* {Boolean} Was a tile drawn? Or null if a beforedraw listener returned
* false.
*/
draw: function() {
var drawn = OpenLayers.Tile.prototype.draw.apply(this, arguments);
if (drawn) {
var shouldDraw = OpenLayers.Tile.prototype.draw.apply(this, arguments);
if (shouldDraw) {
// The layer's reproject option is deprecated.
if (this.layer != this.layer.map.baseLayer && this.layer.reproject) {
// getBoundsFromBaseLayer is defined in deprecated.js.
@@ -158,17 +176,17 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
}
if (this.isLoading) {
//if we're already loading, send 'reload' instead of 'loadstart'.
this._loadEvent = "reload";
this._loadEvent = "reload";
} else {
this.isLoading = true;
this._loadEvent = "loadstart";
}
this.positionTile();
this.renderTile();
} else {
this.positionTile();
} else if (shouldDraw === false) {
this.unload();
}
return drawn;
return shouldDraw;
},
/**
@@ -177,7 +195,6 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
* position it correctly, and set its url.
*/
renderTile: function() {
this.layer.div.appendChild(this.getTile());
if (this.layer.async) {
// Asynchronous image requests call the asynchronous getURL method
// on the layer to fetch an image that covers 'this.bounds'.
@@ -278,18 +295,34 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
return this.imgDiv;
},
/**
* APIMethod: setImage
* Sets the image element for this tile. This method should only be called
* from beforeload listeners.
*
* Parameters
* img - {HTMLImageElement} The image to use for this tile.
*/
setImage: function(img) {
this.imgDiv = img;
},
/**
* Method: initImage
* Creates the content for the frame on the tile.
*/
initImage: function() {
this.events.triggerEvent('beforeload');
this.layer.div.appendChild(this.getTile());
this.events.triggerEvent(this._loadEvent);
var img = this.getImage();
if (this.url && img.getAttribute("src") == this.url) {
this.onImageLoad();
this._loadTimeout = window.setTimeout(
OpenLayers.Function.bind(this.onImageLoad, this), 0
);
} else {
OpenLayers.Event.stopObservingElement(img);
this.stopLoading();
if (this.crossOriginKeyword) {
img.removeAttribute("crossorigin");
}
@@ -328,7 +361,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
} else {
// Remove reference to the image, and leave it to the browser's
// caching and garbage collection.
OpenLayers.Event.stopObservingElement(this.imgDiv);
this.stopLoading();
this.imgDiv = null;
if (img.parentNode) {
img.parentNode.removeChild(img);
@@ -378,7 +411,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
*/
onImageLoad: function() {
var img = this.imgDiv;
OpenLayers.Event.stopObservingElement(img);
this.stopLoading();
img.style.visibility = 'inherit';
img.style.opacity = this.layer.opacity;
this.isLoading = false;
@@ -409,6 +442,16 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
}
}
},
/**
* Method: stopLoading
* Stops a loading sequence so <onImageLoad> won't be executed.
*/
stopLoading: function() {
OpenLayers.Event.stopObservingElement(this.imgDiv);
window.clearTimeout(this._loadTimeout);
delete this._loadTimeout;
},
/**
* APIMethod: getCanvasContext
lib/OpenLayers/TileManager.js
+404
View File
@@ -0,0 +1,404 @@
/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the 2-clause BSD license.
* See license.txt in the OpenLayers distribution or repository for the
* full text of the license. */
/**
* @requires OpenLayers/Layer/Grid.js
* @requires OpenLayers/Util.js
* @requires OpenLayers/BaseTypes.js
* @requires OpenLayers/BaseTypes/Element.js
*/
/**
* Class: OpenLayers.TileManager
* Provides queueing of image requests and caching of image elements.
*
* Queueing avoids unnecessary image requests while changing zoom levels
* quickly, and helps improve dragging performance on mobile devices that show
* a lag in dragging when loading of new images starts. <zoomDelay> and
* <moveDelay> are the configuration options to control this behavior.
*
* Caching avoids setting the src on image elements for images that have already
* been used. Several maps can share a TileManager instance, in which case each
* map gets its own tile queue, but all maps share the same tile cache.
*/
OpenLayers.TileManager = OpenLayers.Class({
/**
* APIProperty: cacheSize
* {Number} Number of image elements to keep referenced in this instance's
* cache for fast reuse. Default is 256.
*/
cacheSize: 256,
/**
* APIProperty: moveDelay
* {Number} Delay in milliseconds after a map's move event before loading
* tiles. Default is 100.
*/
moveDelay: 100,
/**
* APIProperty: zoomDelay
* {Number} Delay in milliseconds after a map's zoomend event before loading
* tiles. Default is 200.
*/
zoomDelay: 200,
/**
* Property: maps
* {Array(<OpenLayers.Map>)} The maps to manage tiles on.
*/
maps: null,
/**
* Property: tileQueueId
* {Object} The ids of the <drawTilesFromQueue> loop, keyed by map id.
*/
tileQueueId: null,
/**
* Property: tileQueue
* {Object(Array(<OpenLayers.Tile>))} Tiles queued for drawing, keyed by
* map id.
*/
tileQueue: null,
/**
* Property: tileCache
* {Object} Cached image elements, keyed by URL.
*/
tileCache: null,
/**
* Property: tileCacheIndex
* {Array(String)} URLs of cached tiles. First entry is the least recently
* used.
*/
tileCacheIndex: null,
/**
* Constructor: OpenLayers.TileManager
* Constructor for a new <OpenLayers.TileManager> instance.
*
* Parameters:
* options - {Object} Configuration for this instance.
*/
initialize: function(options) {
OpenLayers.Util.extend(this, options);
this.maps = [];
this.tileQueueId = {};
this.tileQueue = {};
this.tileCache = {};
this.tileCacheIndex = [];
},
/**
* Method: addMap
* Binds this instance to a map
*
* Parameters:
* map - {<OpenLayers.Map>}
*/
addMap: function(map) {
if (this._destroyed) {
return;
}
this.maps.push(map);
this.tileQueue[map.id] = [];
for (var i=0, ii=map.layers.length; i<ii; ++i) {
this.addLayer({layer: map.layers[i]});
}
map.events.on({
move: this.move,
zoomend: this.zoomEnd,
addlayer: this.addLayer,
preremovelayer: this.removeLayer,
scope: this
});
},
/**
* Method: removeMap
* Unbinds this instance from a map
*
* Parameters:
* map - {<OpenLayers.Map>}
*/
removeMap: function(map) {
if (this._destroyed) {
return;
}
window.clearTimeout(this.tileQueueId[map.id]);
if (map.layers) {
for (var i=0, ii=map.layers.length; i<ii; ++i) {
this.removeLayer({layer: map.layers[i]});
}
}
if (map.events) {
map.events.un({
move: this.move,
zoomend: this.zoomEnd,
addlayer: this.addLayer,
preremovelayer: this.removeLayer,
scope: this
});
}
delete this.tileQueue[map.id];
delete this.tileQueueId[map.id];
OpenLayers.Util.removeItem(this.maps, map);
},
/**
* Method: move
* Handles the map's move event
*
* Parameters:
* evt - {Object} Listener argument
*/
move: function(evt) {
this.updateTimeout(evt.object, this.moveDelay);
},
/**
* Method: zoomEnd
* Handles the map's zoomEnd event
*
* Parameters:
* evt - {Object} Listener argument
*/
zoomEnd: function(evt) {
this.updateTimeout(evt.object, this.zoomDelay);
},
/**
* Method: addLayer
* Handles the map's addlayer event
*
* Parameters:
* evt - {Object} The listener argument
*/
addLayer: function(evt) {
var layer = evt.layer;
if (layer instanceof OpenLayers.Layer.Grid) {
layer.events.on({
addtile: this.addTile,
retile: this.clearTileQueue,
scope: this
});
var i, j, tile;
for (i=layer.grid.length-1; i>=0; --i) {
for (j=layer.grid[i].length-1; j>=0; --j) {
tile = layer.grid[i][j];
this.addTile({tile: tile});
if (tile.url) {
this.manageTileCache({object: tile});
}
}
}
}
},
/**
* Method: removeLayer
* Handles the map's preremovelayer event
*
* Parameters:
* evt - {Object} The listener argument
*/
removeLayer: function(evt) {
var layer = evt.layer;
if (layer instanceof OpenLayers.Layer.Grid) {
this.clearTileQueue({object: layer});
if (layer.events) {
layer.events.un({
addtile: this.addTile,
retile: this.clearTileQueue,
scope: this
});
}
if (layer.grid) {
var i, j, tile;
for (i=layer.grid.length-1; i>=0; --i) {
for (j=layer.grid[i].length-1; j>=0; --j) {
tile = layer.grid[i][j];
this.unloadTile({object: tile});
if (tile.url) {
this.manageTileCache({object: tile});
}
}
}
}
}
},
/**
* Method: updateTimeout
* Applies the <moveDelay> or <zoomDelay> to the <drawTilesFromQueue> loop.
*
* Parameters:
* map - {<OpenLayers.Map>} The map to update the timeout for
* delay - {Number} The delay to apply
*/
updateTimeout: function(map, delay) {
window.clearTimeout(this.tileQueueId[map.id]);
if (this.tileQueue[map.id].length) {
this.tileQueueId[map.id] = window.setTimeout(
OpenLayers.Function.bind(function() {
this.drawTilesFromQueue(map);
}, this), delay
);
}
},
/**
* Method: addTile
* Listener for the layer's addtile event
*
* Parameters:
* evt - {Object} The listener argument
*/
addTile: function(evt) {
evt.tile.events.on({
beforedraw: this.queueTileDraw,
beforeload: this.manageTileCache,
loadend: this.addToCache,
unload: this.unloadTile,
scope: this
});
},
/**
* Method: unloadTile
* Listener for the tile's unload event
*
* Parameters:
* evt - {Object} The listener argument
*/
unloadTile: function(evt) {
var tile = evt.object;
tile.events.un({
beforedraw: this.queueTileDraw,
beforeload: this.manageTileCache,
loadend: this.addToCache,
unload: this.unloadTile,
scope: this
});
OpenLayers.Util.removeItem(this.tileQueue[tile.layer.map.id], tile);
},
/**
* Method: queueTileDraw
* Adds a tile to the queue that will draw it.
*
* Parameters:
* evt - {Object} Listener argument of the tile's beforedraw event
*/
queueTileDraw: function(evt) {
var tile = evt.object;
var queued = false;
var layer = tile.layer;
// queue only if image with same url not cached already
if (layer.url && (layer.async ||
!this.tileCache[layer.getURL(tile.bounds)])) {
// add to queue only if not in queue already
var tileQueue = this.tileQueue[layer.map.id];
if (!~OpenLayers.Util.indexOf(tileQueue, tile)) {
tileQueue.push(tile);
}
queued = true;
}
return !queued;
},
/**
* Method: drawTilesFromQueue
* Draws tiles from the tileQueue, and unqueues the tiles
*/
drawTilesFromQueue: function(map) {
var tileQueue = this.tileQueue[map.id];
while (tileQueue.length) {
tileQueue.shift().draw(true);
}
},
/**
* Method: manageTileCache
* Adds, updates, removes and fetches cache entries.
*
* Parameters:
* evt - {Object} Listener argument of the tile's beforeload event
*/
manageTileCache: function(evt) {
var tile = evt.object;
var img = this.tileCache[tile.url];
// only use image from cache if it is not on a layer already
if (img && (!img.parentNode ||
OpenLayers.Element.hasClass(img.parentNode, 'olBackBuffer'))) {
if (tile.layer.backBuffer) {
img.style.opacity = 0;
img.style.visibility = 'hidden';
}
tile.setImage(img);
// LRU - move tile to the end of the array to mark it as the most
// recently used
OpenLayers.Util.removeItem(this.tileCacheIndex, tile.url);
this.tileCacheIndex.push(tile.url);
}
},
/**
* Method: addToCache
*
* Parameters:
* evt - {Object} Listener argument for the tile's loadend event
*/
addToCache: function(evt) {
var tile = evt.object;
if (!this.tileCache[tile.url]) {
if (!OpenLayers.Element.hasClass(tile.imgDiv, 'olImageLoadError')) {
if (this.tileCacheIndex.length >= this.cacheSize) {
delete this.tileCache[this.tileCacheIndex[0]];
this.tileCacheIndex.shift();
}
this.tileCache[tile.url] = tile.imgDiv;
this.tileCacheIndex.push(tile.url);
}
}
},
/**
* Method: clearTileQueue
* Clears the tile queue from tiles of a specific layer
*
* Parameters:
* evt - {Object} Listener argument of the layer's retile event
*/
clearTileQueue: function(evt) {
var layer = evt.object;
var tileQueue = this.tileQueue[layer.map.id];
for (var i=tileQueue.length-1; i>=0; --i) {
if (tileQueue[i].layer === layer) {
tileQueue.splice(i, 1);
}
}
},
/**
* Method: destroy
*/
destroy: function() {
for (var i=this.maps.length-1; i>=0; --i) {
this.removeMap(this.maps[i]);
}
this.maps = null;
this.tileQueue = null;
this.tileQueueId = null;
this.tileCache = null;
this.tileCacheIndex = null;
this._destroyed = true;
}
});