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/* Copyright (c) 2006-2013 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/HTTPRequest.js
* @requires OpenLayers/Tile/Image.js
*/
/**
* Class: OpenLayers.Layer.Grid
* Base class for layers that use a lattice of tiles. Create a new grid
* layer with the <OpenLayers.Layer.Grid> constructor.
*
* Inherits from:
* - <OpenLayers.Layer.HTTPRequest>
*/
OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
/**
* APIProperty: tileSize
* {<OpenLayers.Size>}
*/
tileSize: null,
/**
* Property: tileOriginCorner
* {String} If the <tileOrigin> property is not provided, the tile origin
* will be derived from the layer's <maxExtent>. The corner of the
* <maxExtent> used is determined by this property. Acceptable values
* are "tl" (top left), "tr" (top right), "bl" (bottom left), and "br"
* (bottom right). Default is "bl".
*/
tileOriginCorner: "bl",
/**
* APIProperty: tileOrigin
* {<OpenLayers.LonLat>} Optional origin for aligning the grid of tiles.
* If provided, requests for tiles at all resolutions will be aligned
* with this location (no tiles shall overlap this location). If
* not provided, the grid of tiles will be aligned with the layer's
* <maxExtent>. Default is ``null``.
*/
tileOrigin: null,
/** APIProperty: tileOptions
* {Object} optional configuration options for <OpenLayers.Tile> instances
* created by this Layer, if supported by the tile class.
*/
tileOptions: null,
/**
* APIProperty: tileClass
* {<OpenLayers.Tile>} The tile class to use for this layer.
* Defaults is OpenLayers.Tile.Image.
*/
tileClass: OpenLayers.Tile.Image,
/**
* Property: grid
* {Array(Array(<OpenLayers.Tile>))} This is an array of rows, each row is
* an array of tiles.
*/
grid: null,
/**
* APIProperty: singleTile
* {Boolean} Moves the layer into single-tile mode, meaning that one tile
* will be loaded. The tile's size will be determined by the 'ratio'
* property. When the tile is dragged such that it does not cover the
* entire viewport, it is reloaded.
*/
singleTile: false,
/** APIProperty: ratio
* {Float} Used only when in single-tile mode, this specifies the
* ratio of the size of the single tile to the size of the map.
* Default value is 1.5.
*/
ratio: 1.5,
/**
* APIProperty: buffer
* {Integer} Used only when in gridded mode, this specifies the number of
* extra rows and colums of tiles on each side which will
* surround the minimum grid tiles to cover the map.
* For very slow loading layers, a larger value may increase
* performance somewhat when dragging, but will increase bandwidth
* use significantly.
*/
buffer: 0,
/**
* APIProperty: transitionEffect
* {String} The transition effect to use when the map is zoomed.
* Two posible values:
*
* "resize" - Existing tiles are resized on zoom to provide a visual
* effect of the zoom having taken place immediately. As the
* new tiles become available, they are drawn on top of the
* resized tiles (this is the default setting).
* "map-resize" - Existing tiles are resized on zoom and placed below the
* base layer. New tiles for the base layer will cover existing tiles.
* This setting is recommended when having an overlay duplicated during
* the transition is undesirable (e.g. street labels or big transparent
* fills).
* null - No transition effect.
*
* Using "resize" on non-opaque layers can cause undesired visual
* effects. Set transitionEffect to null in this case.
*/
transitionEffect: "resize",
/**
* APIProperty: numLoadingTiles
* {Integer} How many tiles are still loading?
*/
numLoadingTiles: 0,
/**
* Property: serverResolutions
* {Array(Number}} This property is documented in subclasses as
* an API property.
*/
serverResolutions: null,
/**
* Property: loading
* {Boolean} Indicates if tiles are being loaded.
*/
loading: false,
/**
* Property: backBuffer
* {DOMElement} The back buffer.
*/
backBuffer: null,
/**
* Property: gridResolution
* {Number} The resolution of the current grid. Used for backbuffer and
* client zoom. This property is updated every time the grid is
* initialized.
*/
gridResolution: null,
/**
* Property: backBufferResolution
* {Number} The resolution of the current back buffer. This property is
* updated each time a back buffer is created.
*/
backBufferResolution: null,
/**
* Property: backBufferLonLat
* {Object} The top-left corner of the current back buffer. Includes lon
* and lat properties. This object is updated each time a back buffer
* is created.
*/
backBufferLonLat: null,
/**
* Property: backBufferTimerId
* {Number} The id of the back buffer timer. This timer is used to
* delay the removal of the back buffer, thereby preventing
* flash effects caused by tile animation.
*/
backBufferTimerId: null,
/**
* APIProperty: removeBackBufferDelay
* {Number} Delay for removing the backbuffer when all tiles have finished
* loading. Can be set to 0 when no css opacity transitions for the
* olTileImage class are used. Default is 0 for <singleTile> layers,
* 2500 for tiled layers. See <className> for more information on
* tile animation.
*/
removeBackBufferDelay: null,
/**
* APIProperty: className
* {String} Name of the class added to the layer div. If not set in the
* options passed to the constructor then className defaults to
* "olLayerGridSingleTile" for single tile layers (see <singleTile>),
* and "olLayerGrid" for non single tile layers.
*
* Note:
*
* The displaying of tiles is not animated by default for single tile
* layers - OpenLayers' default theme (style.css) includes this:
* (code)
* .olLayerGrid .olTileImage {
* -webkit-transition: opacity 0.2s linear;
* -moz-transition: opacity 0.2s linear;
* -o-transition: opacity 0.2s linear;
* transition: opacity 0.2s linear;
* }
* (end)
* To animate tile displaying for any grid layer the following
* CSS rule can be used:
* (code)
* .olTileImage {
* -webkit-transition: opacity 0.2s linear;
* -moz-transition: opacity 0.2s linear;
* -o-transition: opacity 0.2s linear;
* transition: opacity 0.2s linear;
* }
* (end)
* In that case, to avoid flash effects, <removeBackBufferDelay>
* should not be zero.
*/
className: null,
/**
* Register a listener for a particular event with the following syntax:
* (code)
* layer.events.register(type, obj, listener);
* (end)
*
* Listeners will be called with a reference to an event object. The
* properties of this event depends on exactly what happened.
*
* All event objects have at least the following properties:
* object - {Object} A reference to layer.events.object.
* 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.
* tileloaded - Triggered when each new tile is
* loaded, as a means of progress update to listeners.
* listeners can access 'numLoadingTiles' if they wish to keep
* track of the loading progress. Listeners are called with an object
* with a 'tile' property as first argument, making the loaded tile
* available to the listener, and an 'aborted' property, which will be
* true when loading was aborted and no tile data is available.
* tileerror - Triggered before the tileloaded event (i.e. when the tile is
* 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.
*/
/**
* Property: gridLayout
* {Object} Object containing properties tilelon, tilelat, startcol,
* startrow
*/
gridLayout: null,
/**
* Property: rowSign
* {Number} 1 for grids starting at the top, -1 for grids starting at the
* bottom. This is used for several grid index and offset calculations.
*/
rowSign: null,
/**
* Property: transitionendEvents
* {Array} Event names for transitionend
*/
transitionendEvents: [
'transitionend', 'webkitTransitionEnd', 'otransitionend',
'oTransitionEnd'
],
/**
* Constructor: OpenLayers.Layer.Grid
* Create a new grid layer
*
* Parameters:
* name - {String}
* url - {String}
* params - {Object}
* options - {Object} Hashtable of extra options to tag onto the layer
*/
initialize: function(name, url, params, options) {
OpenLayers.Layer.HTTPRequest.prototype.initialize.apply(this,
arguments);
this.grid = [];
this._removeBackBuffer = OpenLayers.Function.bind(this.removeBackBuffer, this);
this.initProperties();
this.rowSign = this.tileOriginCorner.substr(0, 1) === "t" ? 1 : -1;
},
/**
* Method: initProperties
* Set any properties that depend on the value of singleTile.
* Currently sets removeBackBufferDelay and className
*/
initProperties: function() {
if (this.options.removeBackBufferDelay === undefined) {
this.removeBackBufferDelay = this.singleTile ? 0 : 2500;
}
if (this.options.className === undefined) {
this.className = this.singleTile ? 'olLayerGridSingleTile' :
'olLayerGrid';
}
},
/**
* Method: setMap
*
* Parameters:
* map - {<OpenLayers.Map>} The map.
*/
setMap: function(map) {
OpenLayers.Layer.HTTPRequest.prototype.setMap.call(this, map);
OpenLayers.Element.addClass(this.div, this.className);
},
/**
* Method: removeMap
* Called when the layer is removed from the map.
*
* Parameters:
* map - {<OpenLayers.Map>} The map.
*/
removeMap: function(map) {
this.removeBackBuffer();
},
/**
* APIMethod: destroy
* Deconstruct the layer and clear the grid.
*/
destroy: function() {
this.removeBackBuffer();
this.clearGrid();
this.grid = null;
this.tileSize = null;
OpenLayers.Layer.HTTPRequest.prototype.destroy.apply(this, arguments);
},
/**
* APIMethod: mergeNewParams
* Refetches tiles with new params merged, keeping a backbuffer. Each
* loading new tile will have a css class of '.olTileReplacing'. If a
* stylesheet applies a 'display: none' style to that class, any fade-in
* transition will not apply, and backbuffers for each tile will be removed
* as soon as the tile is loaded.
*
* Parameters:
* newParams - {Object}
*
* Returns:
* redrawn: {Boolean} whether the layer was actually redrawn.
*/
/**
* Method: clearGrid
* Go through and remove all tiles from the grid, calling
* destroy() on each of them to kill circular references
*/
clearGrid:function() {
if (this.grid) {
for(var iRow=0, len=this.grid.length; iRow<len; iRow++) {
var row = this.grid[iRow];
for(var iCol=0, clen=row.length; iCol<clen; iCol++) {
var tile = row[iCol];
this.destroyTile(tile);
}
}
this.grid = [];
this.gridResolution = null;
this.gridLayout = null;
}
},
/**
* APIMethod: addOptions
*
* Parameters:
* newOptions - {Object}
* reinitialize - {Boolean} If set to true, and if resolution options of the
* current baseLayer were changed, the map will be recentered to make
* sure that it is displayed with a valid resolution, and a
* changebaselayer event will be triggered.
*/
addOptions: function (newOptions, reinitialize) {
var singleTileChanged = newOptions.singleTile !== undefined &&
newOptions.singleTile !== this.singleTile;
OpenLayers.Layer.HTTPRequest.prototype.addOptions.apply(this, arguments);
if (this.map && singleTileChanged) {
this.initProperties();
this.clearGrid();
this.tileSize = this.options.tileSize;
this.setTileSize();
this.moveTo(null, true);
}
},
/**
* APIMethod: clone
* Create a clone of this layer
*
* Parameters:
* obj - {Object} Is this ever used?
*
* Returns:
* {<OpenLayers.Layer.Grid>} An exact clone of this OpenLayers.Layer.Grid
*/
clone: function (obj) {
if (obj == null) {
obj = new OpenLayers.Layer.Grid(this.name,
this.url,
this.params,
this.getOptions());
}
//get all additions from superclasses
obj = OpenLayers.Layer.HTTPRequest.prototype.clone.apply(this, [obj]);
// copy/set any non-init, non-simple values here
if (this.tileSize != null) {
obj.tileSize = this.tileSize.clone();
}
// we do not want to copy reference to grid, so we make a new array
obj.grid = [];
obj.gridResolution = null;
// same for backbuffer
obj.backBuffer = null;
obj.backBufferTimerId = null;
obj.loading = false;
obj.numLoadingTiles = 0;
return obj;
},
/**
* Method: moveTo
* This function is called whenever the map is moved. All the moving
* of actual 'tiles' is done by the map, but moveTo's role is to accept
* a bounds and make sure the data that that bounds requires is pre-loaded.
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
* zoomChanged - {Boolean}
* dragging - {Boolean}
*/
moveTo:function(bounds, zoomChanged, dragging) {
OpenLayers.Layer.HTTPRequest.prototype.moveTo.apply(this, arguments);
bounds = bounds || this.map.getExtent();
if (bounds != null) {
// if grid is empty or zoom has changed, we *must* re-tile
var forceReTile = !this.grid.length || zoomChanged;
// total bounds of the tiles
var tilesBounds = this.getTilesBounds();
// the new map resolution
var resolution = this.map.getResolution();
// the server-supported resolution for the new map resolution
var serverResolution = this.getServerResolution(resolution);
if (this.singleTile) {
// We want to redraw whenever even the slightest part of the
// current bounds is not contained by our tile.
// (thus, we do not specify partial -- its default is false)
if ( forceReTile ||
(!dragging && !tilesBounds.containsBounds(bounds))) {
// In single tile mode with no transition effect, we insert
// a non-scaled backbuffer when the layer is moved. But if
// a zoom occurs right after a move, i.e. before the new
// image is received, we need to remove the backbuffer, or
// an ill-positioned image will be visible during the zoom
// transition.
if(zoomChanged && this.transitionEffect !== 'resize') {
this.removeBackBuffer();
}
if(!zoomChanged || this.transitionEffect === 'resize') {
this.applyBackBuffer(resolution);
}
this.initSingleTile(bounds);
}
} else {
// if the bounds have changed such that they are not even
// *partially* contained by our tiles (e.g. when user has
// programmatically panned to the other side of the earth on
// zoom level 18), then moveGriddedTiles could potentially have
// to run through thousands of cycles, so we want to reTile
// instead (thus, partial true).
forceReTile = forceReTile ||
!tilesBounds.intersectsBounds(bounds, {
worldBounds: this.map.baseLayer.wrapDateLine &&
this.map.getMaxExtent()
});
if(forceReTile) {
if(zoomChanged && (this.transitionEffect === 'resize' ||
this.gridResolution === resolution)) {
this.applyBackBuffer(resolution);
}
this.initGriddedTiles(bounds);
} else {
this.moveGriddedTiles();
}
}
}
},
/**
* Method: getTileData
* Given a map location, retrieve a tile and the pixel offset within that
* tile corresponding to the location. If there is not an existing
* tile in the grid that covers the given location, null will be
* returned.
*
* Parameters:
* loc - {<OpenLayers.LonLat>} map location
*
* Returns:
* {Object} Object with the following properties: tile ({<OpenLayers.Tile>}),
* i ({Number} x-pixel offset from top left), and j ({Integer} y-pixel
* offset from top left).
*/
getTileData: function(loc) {
var data = null,
x = loc.lon,
y = loc.lat,
numRows = this.grid.length;
if (this.map && numRows) {
var res = this.map.getResolution(),
tileWidth = this.tileSize.w,
tileHeight = this.tileSize.h,
bounds = this.grid[0][0].bounds,
left = bounds.left,
top = bounds.top;
if (x < left) {
// deal with multiple worlds
if (this.map.baseLayer.wrapDateLine) {
var worldWidth = this.map.getMaxExtent().getWidth();
var worldsAway = Math.ceil((left - x) / worldWidth);
x += worldWidth * worldsAway;
}
}
// tile distance to location (fractional number of tiles);
var dtx = (x - left) / (res * tileWidth);
var dty = (top - y) / (res * tileHeight);
// index of tile in grid
var col = Math.floor(dtx);
var row = Math.floor(dty);
if (row >= 0 && row < numRows) {
var tile = this.grid[row][col];
if (tile) {
data = {
tile: tile,
// pixel index within tile
i: Math.floor((dtx - col) * tileWidth),
j: Math.floor((dty - row) * tileHeight)
};
}
}
}
return data;
},
/**
* Method: destroyTile
*
* Parameters:
* tile - {<OpenLayers.Tile>}
*/
destroyTile: function(tile) {
this.removeTileMonitoringHooks(tile);
tile.destroy();
},
/**
* Method: getServerResolution
* Return the closest server-supported resolution.
*
* Parameters:
* resolution - {Number} The base resolution. If undefined the
* map resolution is used.
*
* Returns:
* {Number} The closest server resolution value.
*/
getServerResolution: function(resolution) {
var distance = Number.POSITIVE_INFINITY;
resolution = resolution || this.map.getResolution();
if(this.serverResolutions &&
OpenLayers.Util.indexOf(this.serverResolutions, resolution) === -1) {
var i, newDistance, newResolution, serverResolution;
for(i=this.serverResolutions.length-1; i>= 0; i--) {
newResolution = this.serverResolutions[i];
newDistance = Math.abs(newResolution - resolution);
if (newDistance > distance) {
break;
}
distance = newDistance;
serverResolution = newResolution;
}
resolution = serverResolution;
}
return resolution;
},
/**
* Method: getServerZoom
* Return the zoom value corresponding to the best matching server
* resolution, taking into account <serverResolutions> and <zoomOffset>.
*
* Returns:
* {Number} The closest server supported zoom. This is not the map zoom
* level, but an index of the server's resolutions array.
*/
getServerZoom: function() {
var resolution = this.getServerResolution();
return this.serverResolutions ?
OpenLayers.Util.indexOf(this.serverResolutions, resolution) :
this.map.getZoomForResolution(resolution) + (this.zoomOffset || 0);
},
/**
* Method: applyBackBuffer
* Create, insert, scale and position a back buffer for the layer.
*
* Parameters:
* resolution - {Number} The resolution to transition to.
*/
applyBackBuffer: function(resolution) {
if(this.backBufferTimerId !== null) {
this.removeBackBuffer();
}
var backBuffer = this.backBuffer;
if(!backBuffer) {
backBuffer = this.createBackBuffer();
if(!backBuffer) {
return;
}
if (resolution === this.gridResolution) {
this.div.insertBefore(backBuffer, this.div.firstChild);
} else {
this.map.baseLayer.div.parentNode.insertBefore(backBuffer, this.map.baseLayer.div);
}
this.backBuffer = backBuffer;
// set some information in the instance for subsequent
// calls to applyBackBuffer where the same back buffer
// is reused
var topLeftTileBounds = this.grid[0][0].bounds;
this.backBufferLonLat = {
lon: topLeftTileBounds.left,
lat: topLeftTileBounds.top
};
this.backBufferResolution = this.gridResolution;
}
var ratio = this.backBufferResolution / resolution;
// scale the tiles inside the back buffer
var tiles = backBuffer.childNodes, tile;
for (var i=tiles.length-1; i>=0; --i) {
tile = tiles[i];
tile.style.top = ((ratio * tile._i * tile._h) | 0) + 'px';
tile.style.left = ((ratio * tile._j * tile._w) | 0) + 'px';
tile.style.width = Math.round(ratio * tile._w) + 'px';
tile.style.height = Math.round(ratio * tile._h) + 'px';
}
// and position it (based on the grid's top-left corner)
var position = this.getViewPortPxFromLonLat(
this.backBufferLonLat, resolution);
var leftOffset = this.map.layerContainerOriginPx.x;
var topOffset = this.map.layerContainerOriginPx.y;
backBuffer.style.left = Math.round(position.x - leftOffset) + 'px';
backBuffer.style.top = Math.round(position.y - topOffset) + 'px';
},
/**
* Method: createBackBuffer
* Create a back buffer.
*
* Returns:
* {DOMElement} The DOM element for the back buffer, undefined if the
* grid isn't initialized yet.
*/
createBackBuffer: function() {
var backBuffer;
if(this.grid.length > 0) {
backBuffer = document.createElement('div');
backBuffer.id = this.div.id + '_bb';
backBuffer.className = 'olBackBuffer';
backBuffer.style.position = 'absolute';
var map = this.map;
backBuffer.style.zIndex = this.transitionEffect === 'resize' ?
this.getZIndex() - 1 :
// 'map-resize':
map.Z_INDEX_BASE.BaseLayer -
(map.getNumLayers() - map.getLayerIndex(this));
for(var i=0, lenI=this.grid.length; i<lenI; i++) {
for(var j=0, lenJ=this.grid[i].length; j<lenJ; j++) {
var tile = this.grid[i][j],
markup = this.grid[i][j].createBackBuffer();
if (markup) {
markup._i = i;
markup._j = j;
markup._w = tile.size.w;
markup._h = tile.size.h;
markup.id = tile.id + '_bb';
backBuffer.appendChild(markup);
}
}
}
}
return backBuffer;
},
/**
* Method: removeBackBuffer
* Remove back buffer from DOM.
*/
removeBackBuffer: function() {
if (this._transitionElement) {
for (var i=this.transitionendEvents.length-1; i>=0; --i) {
OpenLayers.Event.stopObserving(this._transitionElement,
this.transitionendEvents[i], this._removeBackBuffer);
}
delete this._transitionElement;
}
if(this.backBuffer) {
if (this.backBuffer.parentNode) {
this.backBuffer.parentNode.removeChild(this.backBuffer);
}
this.backBuffer = null;
this.backBufferResolution = null;
if(this.backBufferTimerId !== null) {
window.clearTimeout(this.backBufferTimerId);
this.backBufferTimerId = null;
}
}
},
/**
* Method: moveByPx
* Move the layer based on pixel vector.
*
* Parameters:
* dx - {Number}
* dy - {Number}
*/
moveByPx: function(dx, dy) {
if (!this.singleTile) {
this.moveGriddedTiles();
}
},
/**
* APIMethod: setTileSize
* Check if we are in singleTile mode and if so, set the size as a ratio
* of the map size (as specified by the layer's 'ratio' property).
*
* Parameters:
* size - {<OpenLayers.Size>}
*/
setTileSize: function(size) {
if (this.singleTile) {
size = this.map.getSize();
size.h = parseInt(size.h * this.ratio, 10);
size.w = parseInt(size.w * this.ratio, 10);
}
OpenLayers.Layer.HTTPRequest.prototype.setTileSize.apply(this, [size]);
},
/**
* APIMethod: getTilesBounds
* Return the bounds of the tile grid.
*
* Returns:
* {<OpenLayers.Bounds>} A Bounds object representing the bounds of all the
* currently loaded tiles (including those partially or not at all seen
* onscreen).
*/
getTilesBounds: function() {
var bounds = null;
var length = this.grid.length;
if (length) {
var bottomLeftTileBounds = this.grid[length - 1][0].bounds,
width = this.grid[0].length * bottomLeftTileBounds.getWidth(),
height = this.grid.length * bottomLeftTileBounds.getHeight();
bounds = new OpenLayers.Bounds(bottomLeftTileBounds.left,
bottomLeftTileBounds.bottom,
bottomLeftTileBounds.left + width,
bottomLeftTileBounds.bottom + height);
}
return bounds;
},
/**
* Method: initSingleTile
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
*/
initSingleTile: function(bounds) {
this.events.triggerEvent("retile");
//determine new tile bounds
var center = bounds.getCenterLonLat();
var tileWidth = bounds.getWidth() * this.ratio;
var tileHeight = bounds.getHeight() * this.ratio;
var tileBounds =
new OpenLayers.Bounds(center.lon - (tileWidth/2),
center.lat - (tileHeight/2),
center.lon + (tileWidth/2),
center.lat + (tileHeight/2));
var px = this.map.getLayerPxFromLonLat({
lon: tileBounds.left,
lat: tileBounds.top
});
if (!this.grid.length) {
this.grid[0] = [];
}
var tile = this.grid[0][0];
if (!tile) {
tile = this.addTile(tileBounds, px);
this.addTileMonitoringHooks(tile);
tile.draw();
this.grid[0][0] = tile;
} else {
tile.moveTo(tileBounds, px);
}
//remove all but our single tile
this.removeExcessTiles(1,1);
// store the resolution of the grid
this.gridResolution = this.getServerResolution();
},
/**
* Method: calculateGridLayout
* Generate parameters for the grid layout.
*
* Parameters:
* bounds - {<OpenLayers.Bound>|Object} OpenLayers.Bounds or an
* object with a 'left' and 'top' properties.
* origin - {<OpenLayers.LonLat>|Object} OpenLayers.LonLat or an
* object with a 'lon' and 'lat' properties.
* resolution - {Number}
*
* Returns:
* {Object} Object containing properties tilelon, tilelat, startcol,
* startrow
*/
calculateGridLayout: function(bounds, origin, resolution) {
var tilelon = resolution * this.tileSize.w;
var tilelat = resolution * this.tileSize.h;
var offsetlon = bounds.left - origin.lon;
var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
var rowSign = this.rowSign;
var offsetlat = rowSign * (origin.lat - bounds.top + tilelat);
var tilerow = Math[~rowSign ? 'floor' : 'ceil'](offsetlat/tilelat) - this.buffer * rowSign;
return {
tilelon: tilelon, tilelat: tilelat,
startcol: tilecol, startrow: tilerow
};
},
/**
* Method: getTileOrigin
* Determine the origin for aligning the grid of tiles. If a <tileOrigin>
* property is supplied, that will be returned. Otherwise, the origin
* will be derived from the layer's <maxExtent> property. In this case,
* the tile origin will be the corner of the <maxExtent> given by the
* <tileOriginCorner> property.
*
* Returns:
* {<OpenLayers.LonLat>} The tile origin.
*/
getTileOrigin: function() {
var origin = this.tileOrigin;
if (!origin) {
var extent = this.getMaxExtent();
var edges = ({
"tl": ["left", "top"],
"tr": ["right", "top"],
"bl": ["left", "bottom"],
"br": ["right", "bottom"]
})[this.tileOriginCorner];
origin = new OpenLayers.LonLat(extent[edges[0]], extent[edges[1]]);
}
return origin;
},
/**
* Method: getTileBoundsForGridIndex
*
* Parameters:
* row - {Number} The row of the grid
* col - {Number} The column of the grid
*
* Returns:
* {<OpenLayers.Bounds>} The bounds for the tile at (row, col)
*/
getTileBoundsForGridIndex: function(row, col) {
var origin = this.getTileOrigin();
var tileLayout = this.gridLayout;
var tilelon = tileLayout.tilelon;
var tilelat = tileLayout.tilelat;
var startcol = tileLayout.startcol;
var startrow = tileLayout.startrow;
var rowSign = this.rowSign;
return new OpenLayers.Bounds(
origin.lon + (startcol + col) * tilelon,
origin.lat - (startrow + row * rowSign) * tilelat * rowSign,
origin.lon + (startcol + col + 1) * tilelon,
origin.lat - (startrow + (row - 1) * rowSign) * tilelat * rowSign
);
},
/**
* Method: initGriddedTiles
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
*/
initGriddedTiles:function(bounds) {
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
var viewSize = this.map.getSize();
var origin = this.getTileOrigin();
var resolution = this.map.getResolution(),
serverResolution = this.getServerResolution(),
ratio = resolution / serverResolution,
tileSize = {
w: this.tileSize.w / ratio,
h: this.tileSize.h / ratio
};
var minRows = Math.ceil(viewSize.h/tileSize.h) +
2 * this.buffer + 1;
var minCols = Math.ceil(viewSize.w/tileSize.w) +
2 * this.buffer + 1;
var tileLayout = this.calculateGridLayout(bounds, origin, serverResolution);
this.gridLayout = tileLayout;
var tilelon = tileLayout.tilelon;
var tilelat = tileLayout.tilelat;
var layerContainerDivLeft = this.map.layerContainerOriginPx.x;
var layerContainerDivTop = this.map.layerContainerOriginPx.y;
var tileBounds = this.getTileBoundsForGridIndex(0, 0);
var startPx = this.map.getViewPortPxFromLonLat(
new OpenLayers.LonLat(tileBounds.left, tileBounds.top)
);
startPx.x = Math.round(startPx.x) - layerContainerDivLeft;
startPx.y = Math.round(startPx.y) - layerContainerDivTop;
var tileData = [], center = this.map.getCenter();
var rowidx = 0;
do {
var row = this.grid[rowidx];
if (!row) {
row = [];
this.grid.push(row);
}
var colidx = 0;
do {
tileBounds = this.getTileBoundsForGridIndex(rowidx, colidx);
var px = startPx.clone();
px.x = px.x + colidx * Math.round(tileSize.w);
px.y = px.y + rowidx * Math.round(tileSize.h);
var tile = row[colidx];
if (!tile) {
tile = this.addTile(tileBounds, px);
this.addTileMonitoringHooks(tile);
row.push(tile);
} else {
tile.moveTo(tileBounds, px, false);
}
var tileCenter = tileBounds.getCenterLonLat();
tileData.push({
tile: tile,
distance: Math.pow(tileCenter.lon - center.lon, 2) +
Math.pow(tileCenter.lat - center.lat, 2)
});
colidx += 1;
} while ((tileBounds.right <= bounds.right + tilelon * this.buffer)
|| colidx < minCols);
rowidx += 1;
} while((tileBounds.bottom >= bounds.bottom - tilelat * this.buffer)
|| rowidx < minRows);
//shave off exceess rows and colums
this.removeExcessTiles(rowidx, colidx);
var resolution = this.getServerResolution();
// store the resolution of the grid
this.gridResolution = resolution;
//now actually draw the tiles
tileData.sort(function(a, b) {
return a.distance - b.distance;
});
for (var i=0, ii=tileData.length; i<ii; ++i) {
tileData[i].tile.draw();
}
},
/**
* Method: getMaxExtent
* Get this layer's maximum extent. (Implemented as a getter for
* potential specific implementations in sub-classes.)
*
* Returns:
* {<OpenLayers.Bounds>}
*/
getMaxExtent: function() {
return this.maxExtent;
},
/**
* APIMethod: addTile
* Create a tile, initialize it, and add it to the layer div.
*
* Parameters
* bounds - {<OpenLayers.Bounds>}
* position - {<OpenLayers.Pixel>}
*
* Returns:
* {<OpenLayers.Tile>} The added OpenLayers.Tile
*/
addTile: function(bounds, position) {
var tile = new this.tileClass(
this, position, bounds, null, this.tileSize, this.tileOptions
);
this.events.triggerEvent("addtile", {tile: tile});
return tile;
},
/**
* Method: addTileMonitoringHooks
* This function takes a tile as input and adds the appropriate hooks to
* the tile so that the layer can keep track of the loading tiles.
*
* Parameters:
* tile - {<OpenLayers.Tile>}
*/
addTileMonitoringHooks: function(tile) {
var replacingCls = 'olTileReplacing';
tile.onLoadStart = function() {
//if that was first tile then trigger a 'loadstart' on the layer
if (this.loading === false) {
this.loading = true;
this.events.triggerEvent("loadstart");
}
this.events.triggerEvent("tileloadstart", {tile: tile});
this.numLoadingTiles++;
if (!this.singleTile && this.backBuffer && this.gridResolution === this.backBufferResolution) {
OpenLayers.Element.addClass(tile.getTile(), replacingCls);
}
};
tile.onLoadEnd = function(evt) {
this.numLoadingTiles--;
var aborted = evt.type === 'unload';
this.events.triggerEvent("tileloaded", {
tile: tile,
aborted: aborted
});
if (!this.singleTile && !aborted && this.backBuffer && this.gridResolution === this.backBufferResolution) {
var tileDiv = tile.getTile();
if (OpenLayers.Element.getStyle(tileDiv, 'display') === 'none') {
var bufferTile = document.getElementById(tile.id + '_bb');
if (bufferTile) {
bufferTile.parentNode.removeChild(bufferTile);
}
}
OpenLayers.Element.removeClass(tileDiv, replacingCls);
}
//if that was the last tile, then trigger a 'loadend' on the layer
if (this.numLoadingTiles === 0) {
if (this.backBuffer) {
if (this.backBuffer.childNodes.length === 0) {
// no tiles transitioning, remove immediately
this.removeBackBuffer();
} else {
// wait until transition has ended or delay has passed
this._transitionElement = aborted ?
this.div.lastChild : tile.imgDiv;
var transitionendEvents = this.transitionendEvents;
for (var i=transitionendEvents.length-1; i>=0; --i) {
OpenLayers.Event.observe(this._transitionElement,
transitionendEvents[i],
this._removeBackBuffer);
}
// the removal of the back buffer is delayed to prevent
// flash effects due to the animation of tile displaying
this.backBufferTimerId = window.setTimeout(
this._removeBackBuffer, this.removeBackBufferDelay
);
}
}
this.loading = false;
this.events.triggerEvent("loadend");
}
};
tile.onLoadError = function() {
this.events.triggerEvent("tileerror", {tile: tile});
};
tile.events.on({
"loadstart": tile.onLoadStart,
"loadend": tile.onLoadEnd,
"unload": tile.onLoadEnd,
"loaderror": tile.onLoadError,
scope: this
});
},
/**
* Method: removeTileMonitoringHooks
* This function takes a tile as input and removes the tile hooks
* that were added in addTileMonitoringHooks()
*
* Parameters:
* tile - {<OpenLayers.Tile>}
*/
removeTileMonitoringHooks: function(tile) {
tile.unload();
tile.events.un({
"loadstart": tile.onLoadStart,
"loadend": tile.onLoadEnd,
"unload": tile.onLoadEnd,
"loaderror": tile.onLoadError,
scope: this
});
},
/**
* Method: moveGriddedTiles
*/
moveGriddedTiles: function() {
var buffer = this.buffer + 1;
while(true) {
var tlTile = this.grid[0][0];
var tlViewPort = {
x: tlTile.position.x +
this.map.layerContainerOriginPx.x,
y: tlTile.position.y +
this.map.layerContainerOriginPx.y
};
var ratio = this.getServerResolution() / this.map.getResolution();
var tileSize = {
w: Math.round(this.tileSize.w * ratio),
h: Math.round(this.tileSize.h * ratio)
};
if (tlViewPort.x > -tileSize.w * (buffer - 1)) {
this.shiftColumn(true, tileSize);
} else if (tlViewPort.x < -tileSize.w * buffer) {
this.shiftColumn(false, tileSize);
} else if (tlViewPort.y > -tileSize.h * (buffer - 1)) {
this.shiftRow(true, tileSize);
} else if (tlViewPort.y < -tileSize.h * buffer) {
this.shiftRow(false, tileSize);
} else {
break;
}
}
},
/**
* Method: shiftRow
* Shifty grid work
*
* Parameters:
* prepend - {Boolean} if true, prepend to beginning.
* if false, then append to end
* tileSize - {Object} rendered tile size; object with w and h properties
*/
shiftRow: function(prepend, tileSize) {
var grid = this.grid;
var rowIndex = prepend ? 0 : (grid.length - 1);
var sign = prepend ? -1 : 1;
var rowSign = this.rowSign;
var tileLayout = this.gridLayout;
tileLayout.startrow += sign * rowSign;
var modelRow = grid[rowIndex];
var row = grid[prepend ? 'pop' : 'shift']();
for (var i=0, len=row.length; i<len; i++) {
var tile = row[i];
var position = modelRow[i].position.clone();
position.y += tileSize.h * sign;
tile.moveTo(this.getTileBoundsForGridIndex(rowIndex, i), position);
}
grid[prepend ? 'unshift' : 'push'](row);
},
/**
* Method: shiftColumn
* Shift grid work in the other dimension
*
* Parameters:
* prepend - {Boolean} if true, prepend to beginning.
* if false, then append to end
* tileSize - {Object} rendered tile size; object with w and h properties
*/
shiftColumn: function(prepend, tileSize) {
var grid = this.grid;
var colIndex = prepend ? 0 : (grid[0].length - 1);
var sign = prepend ? -1 : 1;
var tileLayout = this.gridLayout;
tileLayout.startcol += sign;
for (var i=0, len=grid.length; i<len; i++) {
var row = grid[i];
var position = row[colIndex].position.clone();
var tile = row[prepend ? 'pop' : 'shift']();
position.x += tileSize.w * sign;
tile.moveTo(this.getTileBoundsForGridIndex(i, colIndex), position);
row[prepend ? 'unshift' : 'push'](tile);
}
},
/**
* Method: removeExcessTiles
* When the size of the map or the buffer changes, we may need to
* remove some excess rows and columns.
*
* Parameters:
* rows - {Integer} Maximum number of rows we want our grid to have.
* columns - {Integer} Maximum number of columns we want our grid to have.
*/
removeExcessTiles: function(rows, columns) {
var i, l;
// remove extra rows
while (this.grid.length > rows) {
var row = this.grid.pop();
for (i=0, l=row.length; i<l; i++) {
var tile = row[i];
this.destroyTile(tile);
}
}
// remove extra columns
for (i=0, l=this.grid.length; i<l; i++) {
while (this.grid[i].length > columns) {
var row = this.grid[i];
var tile = row.pop();
this.destroyTile(tile);
}
}
},
/**
* Method: onMapResize
* For singleTile layers, this will set a new tile size according to the
* dimensions of the map pane.
*/
onMapResize: function() {
if (this.singleTile) {
this.clearGrid();
this.setTileSize();
}
},
/**
* APIMethod: getTileBounds
* Returns The tile bounds for a layer given a pixel location.
*
* Parameters:
* viewPortPx - {<OpenLayers.Pixel>} The location in the viewport.
*
* Returns:
* {<OpenLayers.Bounds>} Bounds of the tile at the given pixel location.
*/
getTileBounds: function(viewPortPx) {
var maxExtent = this.maxExtent;
var resolution = this.getResolution();
var tileMapWidth = resolution * this.tileSize.w;
var tileMapHeight = resolution * this.tileSize.h;
var mapPoint = this.getLonLatFromViewPortPx(viewPortPx);
var tileLeft = maxExtent.left + (tileMapWidth *
Math.floor((mapPoint.lon -
maxExtent.left) /
tileMapWidth));
var tileBottom = maxExtent.bottom + (tileMapHeight *
Math.floor((mapPoint.lat -
maxExtent.bottom) /
tileMapHeight));
return new OpenLayers.Bounds(tileLeft, tileBottom,
tileLeft + tileMapWidth,
tileBottom + tileMapHeight);
},
CLASS_NAME: "OpenLayers.Layer.Grid"
});