Files
openlayers/src/ol/renderer/TileLayerRenderer.js
2012-07-07 16:50:22 -06:00

320 lines
9.1 KiB
JavaScript

goog.provide('ol.renderer.TileLayerRenderer');
goog.require('ol.renderer.LayerRenderer');
goog.require('ol.layer.TileLayer');
goog.require('ol.renderer.Composite');
goog.require('ol.TileSet');
goog.require('ol.Bounds');
goog.require('goog.style');
/**
* A single layer renderer that will be created by the composite map renderer.
*
* @constructor
* @param {!Element} container
* @param {!ol.layer.Layer} layer
* @extends {ol.renderer.LayerRenderer}
*/
ol.renderer.TileLayerRenderer = function(container, layer) {
goog.base(this, container, layer);
/**
* @type {Array.<number>}
*/
this.layerResolutions_ = layer.getResolutions();
/**
* @type {Array.<number>}
*/
this.tileOrigin_ = layer.getTileOrigin();
/**
* @type {Array.<number>}
*/
this.tileSize_ = layer.getTileSize();
/**
* @type {boolean}
*/
this.xRight_ = layer.getXRight();
/**
* @type {boolean}
*/
this.yDown_ = layer.getYDown();
/**
* @type {number|undefined}
* @private
*/
this.renderedResolution_ = undefined;
/**
* @type {number|undefined}
* @private
*/
this.renderedTop_ = undefined;
/**
* @type {number|undefined}
* @private
*/
this.renderedRight_ = undefined;
/**
* @type {number|undefined}
* @private
*/
this.renderedBottom_ = undefined;
/**
* @type {number|undefined}
* @private
*/
this.renderedLeft_ = undefined;
/**
* @type {number|undefined}
* @private
*/
this.renderedZ_ = undefined;
};
goog.inherits(ol.renderer.TileLayerRenderer, ol.renderer.LayerRenderer);
/**
* @param {number} resolution
* @return {Array.<number>}
*/
ol.renderer.TileLayerRenderer.prototype.getPreferredResAndZ_ = function(resolution) {
var minDiff = Number.POSITIVE_INFINITY;
var candidate, diff, z, r;
for (var i=0, ii=this.layerResolutions_.length; i<ii; ++i) {
// assumes sorted resolutions
candidate = this.layerResolutions_[i];
diff = Math.abs(resolution - candidate);
if (diff < minDiff) {
z = i;
r = candidate;
minDiff = diff;
} else {
break;
}
}
return [r, z];
};
/**
* Tiles rendered at the current resolution;
* @type {Object}
*/
ol.renderer.TileLayerRenderer.prototype.renderedTiles_ = {};
/**
* Render the layer.
*
* @param {!ol.Loc} center
* @param {number} resolution
*/
ol.renderer.TileLayerRenderer.prototype.draw = function(center, resolution) {
if (resolution !== this.renderedResolution_) {
this.changeResolution_(center, resolution);
}
var pair = this.getPreferredResAndZ_(resolution);
var tileResolution = pair[0];
var tileZ = pair[1];
var scale = resolution / tileResolution;
var containerSize = this.getContainerSize();
var xRight = this.xRight_;
var yDown = this.yDown_;
var halfMapWidth = (resolution * containerSize.width) / 2;
var halfMapHeight = (resolution * containerSize.height) / 2;
var centerX = center.getX();
var centerY = center.getY();
// calculate vector from tile origin to map top-left (in integer pixel space)
var tileOrigin = this.tileOrigin_;
var mapOrigin = [centerX - halfMapWidth, centerY + halfMapHeight];
var pxMap = [
Math.round((mapOrigin[0] - tileOrigin[0]) / resolution),
Math.round((tileOrigin[1] - mapOrigin[1]) / resolution)
];
// desired tile size in fractional pixels
var fpxTileWidth = this.tileSize_[0] / scale;
var fpxTileHeight = this.tileSize_[1] / scale;
// calculate vector from tile origin to top-left tile (in integer pixel space)
var colsLeft = Math.floor(pxMap[0] / fpxTileWidth);
var rowsAbove = Math.floor(pxMap[1] / fpxTileHeight);
var pxTile = [Math.round(colsLeft * fpxTileWidth), Math.round(rowsAbove * fpxTileHeight)];
// offset vector from container origin to top-left tile (in integer pixel space)
var pxOffsetX = Math.round(pxTile[0] - pxMap[0] - this.containerOffset_.x);
var pxOffsetY = Math.round(pxTile[1] - pxMap[1] - this.containerOffset_.y);
// index of the top left tile
var leftTileX = xRight ? colsLeft : (-colsLeft - 1);
var topTileY = yDown ? rowsAbove : (-rowsAbove - 1);
var numTilesWide = Math.ceil(containerSize.width / fpxTileWidth);
var numTilesHigh = Math.ceil(containerSize.height / fpxTileHeight);
if (this.containerOffset_.x !== -pxOffsetX) {
numTilesWide += 1;
}
if (this.containerOffset_.y !== -pxOffsetY) {
numTilesHigh += 1;
}
var pxMinX = pxOffsetX;
var pxMinY = pxOffsetY;
var pxTileLeft = pxMinX;
var tileX, tileY, tile, img, pxTileBottom, pxTileRight, pxTileTop, xyz, append;
var fragment = document.createDocumentFragment();
var newTiles = false;
for (var i=0; i<numTilesWide; ++i) {
pxTileTop = pxMinY;
tileX = xRight ? leftTileX + i : leftTileX - i;
if (scale !== 1) {
pxTileRight = Math.round(pxMinX + ((i+1) * fpxTileWidth));
} else {
pxTileRight = pxTileLeft + fpxTileWidth;
}
for (var j=0; j<numTilesHigh; ++j) {
append = false;
tileY = yDown ? topTileY + j : topTile - j;
xyz = tileX + "," + tileY + "," + tileZ;
if (scale !== 1) {
pxTileBottom = Math.round(pxMinY + ((j+1) * fpxTileHeight));
} else {
pxTileBottom = pxTileTop + fpxTileHeight;
}
img = null;
tile = this.renderedTiles_[xyz];
if (!tile) {
tile = this.layer_.getTileForXYZ(tileX, tileY, tileZ);
if (tile) {
if (!tile.isLoaded() && !tile.isLoading()) {
tile.load();
}
this.renderedTiles_[xyz] = tile;
img = tile.getImg();
img.style.top = pxTileTop + "px";
img.style.left = pxTileLeft + "px";
/**
* We need to set the size here even if the scale is 1
* because the image may have been scaled previously. If
* we want to avoid setting size unnecessarily, the tile
* should keep track of the scale.
*/
img.style.height = (pxTileRight - pxTileLeft) + "px";
img.style.width = (pxTileBottom - pxTileTop) + "px";
goog.dom.appendChild(fragment, img);
newTiles = true;
}
}
pxTileTop = pxTileBottom;
}
pxTileLeft = pxTileRight;
}
if (newTiles) {
this.container_.appendChild(fragment);
}
this.renderedResolution_ = resolution;
this.renderedTop_ = topTileY;
this.renderedRight_ = tileX;
this.renderedBottom_ = tileY;
this.renderedLeft_ = leftTileX;
this.renderedZ_ = tileZ;
this.removeInvisibleTiles_();
};
/**
* Get rid of tiles outside the rendered extent.
*/
ol.renderer.TileLayerRenderer.prototype.removeInvisibleTiles_ = function() {
var index, prune, x, y, z, tile;
var xRight = this.xRight_;
var yDown = this.yDown_;
var top = this.renderedTop_;
var right = this.renderedRight_;
var bottom = this.renderedBottom_;
var left = this.renderedLeft_;
for (var xyz in this.renderedTiles_) {
index = xyz.split(",");
x = +index[0];
y = +index[1];
z = +index[2];
prune = this.renderedZ_ !== z ||
// beyond on the left side
(xRight ? x < left : x > left) ||
// beyond on the right side
(xRight ? x > right : x < right) ||
// above
(yDown ? y < top : y > top) ||
// below
(yDown ? y > bottom : y < bottom);
if (prune) {
tile = this.renderedTiles_[xyz];
delete this.renderedTiles_[xyz];
this.container_.removeChild(tile.getImg());
}
}
};
/**
* Deal with changes in resolution.
* TODO: implement the animation
*
* @param {ol.Loc} center New center.
* @param {number} resolution New resolution.
*/
ol.renderer.TileLayerRenderer.prototype.changeResolution_ = function(center, resolution) {
this.renderedTiles_ = {};
goog.dom.removeChildren(this.container_);
};
/**
* Get an identifying string for this renderer.
*
* @export
* @returns {string}
*/
ol.renderer.TileLayerRenderer.getType = function() {
// TODO: revisit
return "tile";
};
/**
* Determine if this renderer type is supported in this environment.
*
* @export
* @return {boolean} This renderer is supported.
*/
ol.renderer.TileLayerRenderer.isSupported = function() {
return true;
};
/**
* Determine if this renderer can render the given layer.
*
* @export
* @param {ol.layer.Layer} layer The candidate layer.
* @return {boolean} This renderer is capable of rendering the layer.
*/
ol.renderer.TileLayerRenderer.canRender = function(layer) {
return layer instanceof ol.layer.TileLayer;
};
ol.renderer.Composite.register(ol.renderer.TileLayerRenderer);