Files
openlayers/src/ol/renderer/canvas/canvastilelayerrenderer.js
2016-02-29 21:13:31 +01:00

327 lines
11 KiB
JavaScript

// FIXME find correct globalCompositeOperation
goog.provide('ol.renderer.canvas.TileLayer');
goog.require('goog.asserts');
goog.require('ol.TileRange');
goog.require('ol.TileState');
goog.require('ol.array');
goog.require('ol.dom');
goog.require('ol.extent');
goog.require('ol.layer.Tile');
goog.require('ol.object');
goog.require('ol.render.EventType');
goog.require('ol.renderer.canvas.Layer');
goog.require('ol.source.Tile');
/**
* @constructor
* @extends {ol.renderer.canvas.Layer}
* @param {ol.layer.Tile} tileLayer Tile layer.
*/
ol.renderer.canvas.TileLayer = function(tileLayer) {
goog.base(this, tileLayer);
/**
* @private
* @type {!Object.<string, Array.<ol.Extent>>}
*/
this.clipExtents_ = {};
/**
* @private
* @type {CanvasRenderingContext2D}
*/
this.context_ = ol.dom.createCanvasContext2D();
/**
* @private
* @type {Array.<ol.Tile|undefined>}
*/
this.renderedTiles_ = null;
/**
* @private
* @type {ol.Extent}
*/
this.tmpExtent_ = ol.extent.createEmpty();
};
goog.inherits(ol.renderer.canvas.TileLayer, ol.renderer.canvas.Layer);
/**
* @inheritDoc
*/
ol.renderer.canvas.TileLayer.prototype.composeFrame = function(
frameState, layerState, context) {
var pixelRatio = frameState.pixelRatio;
var viewState = frameState.viewState;
var center = viewState.center;
var projection = viewState.projection;
var resolution = viewState.resolution;
var size = frameState.size;
var pixelScale = pixelRatio / resolution;
var layer = this.getLayer();
var source = layer.getSource();
goog.asserts.assertInstanceof(source, ol.source.Tile,
'source is an ol.source.Tile');
var tileGutter = source.getGutter(projection);
var transform = this.getTransform(frameState, 0);
this.dispatchPreComposeEvent(context, frameState, transform);
var renderContext;
if (layer.hasListener(ol.render.EventType.RENDER)) {
// resize and clear
this.context_.canvas.width = context.canvas.width;
this.context_.canvas.height = context.canvas.height;
renderContext = this.context_;
} else {
renderContext = context;
}
var offsetX = Math.round(pixelRatio * size[0] / 2);
var offsetY = Math.round(pixelRatio * size[1] / 2);
// for performance reasons, context.save / context.restore is not used
// to save and restore the transformation matrix and the opacity.
// see http://jsperf.com/context-save-restore-versus-variable
var alpha = renderContext.globalAlpha;
renderContext.globalAlpha = layerState.opacity;
var tileGrid = source.getTileGridForProjection(projection);
var tilesToDraw = this.renderedTiles_;
var clipExtents, clipExtent, currentZ, i, ii, j, jj, insertPoint;
var origin, tile, tileExtent, tileHeight, tileOffsetX, tileOffsetY;
var tilePixelSize, tileWidth;
for (i = 0, ii = tilesToDraw.length; i < ii; ++i) {
tile = tilesToDraw[i];
tileExtent = tileGrid.getTileCoordExtent(
tile.getTileCoord(), this.tmpExtent_);
clipExtents = this.clipExtents_[tile.tileCoord.toString()];
if (clipExtents) {
// Create a clip mask for regions in this low resolution tile that will be
// filled by a higher resolution tile
renderContext.save();
renderContext.beginPath();
renderContext.moveTo((tileExtent[0] - center[0]) * pixelScale + offsetX,
(center[1] - tileExtent[1]) * pixelScale + offsetY);
renderContext.lineTo((tileExtent[2] - center[0]) * pixelScale + offsetX,
(center[1] - tileExtent[1]) * pixelScale + offsetY);
renderContext.lineTo((tileExtent[2] - center[0]) * pixelScale + offsetX,
(center[1] - tileExtent[3]) * pixelScale + offsetY);
renderContext.lineTo((tileExtent[0] - center[0]) * pixelScale + offsetX,
(center[1] - tileExtent[3]) * pixelScale + offsetY);
renderContext.closePath();
for (j = 0, jj = clipExtents.length; j < jj; ++j) {
clipExtent = clipExtents[j];
renderContext.moveTo((clipExtent[0] - center[0]) * pixelScale + offsetX,
(center[1] - clipExtent[1]) * pixelScale + offsetY);
renderContext.lineTo((clipExtent[0] - center[0]) * pixelScale + offsetX,
(center[1] - clipExtent[3]) * pixelScale + offsetY);
renderContext.lineTo((clipExtent[2] - center[0]) * pixelScale + offsetX,
(center[1] - clipExtent[3]) * pixelScale + offsetY);
renderContext.lineTo((clipExtent[2] - center[0]) * pixelScale + offsetX,
(center[1] - clipExtent[1]) * pixelScale + offsetY);
renderContext.closePath();
}
renderContext.clip();
}
currentZ = tile.getTileCoord()[0];
tilePixelSize = source.getTilePixelSize(currentZ, pixelRatio, projection);
insertPoint = ol.extent.getTopLeft(tileExtent);
tileWidth = Math.round(ol.extent.getWidth(tileExtent) * pixelScale);
tileHeight = Math.round(ol.extent.getHeight(tileExtent) * pixelScale);
// Calculate all insert points from a common origin and tile widths to avoid
// gaps caused by rounding
origin = ol.extent.getBottomLeft(tileGrid.getTileCoordExtent(
tileGrid.getTileCoordForCoordAndZ(center, currentZ)));
tileOffsetX = offsetX + Math.round((origin[0] - center[0]) * pixelScale);
tileOffsetY = offsetY + Math.round((center[1] - origin[1]) * pixelScale);
renderContext.drawImage(tile.getImage(), tileGutter, tileGutter,
tilePixelSize[0], tilePixelSize[1],
Math.round((insertPoint[0] - origin[0]) * pixelScale / tileWidth) *
tileWidth + tileOffsetX,
Math.round((origin[1] - insertPoint[1]) * pixelScale / tileHeight) *
tileHeight + tileOffsetY, tileWidth, tileHeight);
if (clipExtents) {
renderContext.restore();
}
}
if (renderContext != context) {
this.dispatchRenderEvent(renderContext, frameState, transform);
context.drawImage(renderContext.canvas, 0, 0);
}
renderContext.globalAlpha = alpha;
this.dispatchPostComposeEvent(context, frameState, transform);
};
/**
* @inheritDoc
*/
ol.renderer.canvas.TileLayer.prototype.prepareFrame = function(
frameState, layerState) {
var pixelRatio = frameState.pixelRatio;
var viewState = frameState.viewState;
var projection = viewState.projection;
var tileLayer = this.getLayer();
goog.asserts.assertInstanceof(tileLayer, ol.layer.Tile,
'layer is an instance of ol.layer.Tile');
var tileSource = tileLayer.getSource();
var tileGrid = tileSource.getTileGridForProjection(projection);
var z = tileGrid.getZForResolution(viewState.resolution);
var tileResolution = tileGrid.getResolution(z);
var center = viewState.center;
var extent;
if (tileResolution == viewState.resolution) {
center = this.snapCenterToPixel(center, tileResolution, frameState.size);
extent = ol.extent.getForViewAndSize(
center, tileResolution, viewState.rotation, frameState.size);
} else {
extent = frameState.extent;
}
if (layerState.extent !== undefined) {
extent = ol.extent.getIntersection(extent, layerState.extent);
}
if (ol.extent.isEmpty(extent)) {
// Return false to prevent the rendering of the layer.
return false;
}
var tileRange = tileGrid.getTileRangeForExtentAndResolution(
extent, tileResolution);
/**
* @type {Object.<number, Object.<string, ol.Tile>>}
*/
var tilesToDrawByZ = {};
tilesToDrawByZ[z] = {};
var findLoadedTiles = this.createLoadedTileFinder(
tileSource, projection, tilesToDrawByZ);
var useInterimTilesOnError = tileLayer.getUseInterimTilesOnError();
var tmpExtent = ol.extent.createEmpty();
var tmpTileRange = new ol.TileRange(0, 0, 0, 0);
var childTileRange, fullyLoaded, tile, x, y;
var drawableTile = (
/**
* @param {!ol.Tile} tile Tile.
* @return {boolean} Tile is selected.
*/
function(tile) {
var tileState = tile.getState();
return tileState == ol.TileState.LOADED ||
tileState == ol.TileState.EMPTY ||
tileState == ol.TileState.ERROR && !useInterimTilesOnError;
});
for (x = tileRange.minX; x <= tileRange.maxX; ++x) {
for (y = tileRange.minY; y <= tileRange.maxY; ++y) {
tile = tileSource.getTile(z, x, y, pixelRatio, projection);
if (!drawableTile(tile) && tile.interimTile) {
tile = tile.interimTile;
}
goog.asserts.assert(tile);
if (drawableTile(tile)) {
tilesToDrawByZ[z][tile.tileCoord.toString()] = tile;
continue;
}
fullyLoaded = tileGrid.forEachTileCoordParentTileRange(
tile.tileCoord, findLoadedTiles, null, tmpTileRange, tmpExtent);
if (!fullyLoaded) {
childTileRange = tileGrid.getTileCoordChildTileRange(
tile.tileCoord, tmpTileRange, tmpExtent);
if (childTileRange) {
findLoadedTiles(z + 1, childTileRange);
}
}
}
}
/** @type {Array.<number>} */
var zs = Object.keys(tilesToDrawByZ).map(Number);
zs.sort(ol.array.numberSafeCompareFunction);
var renderables = [];
var i, ii, currentZ, tileCoordKey, tilesToDraw;
for (i = 0, ii = zs.length; i < ii; ++i) {
currentZ = zs[i];
tilesToDraw = tilesToDrawByZ[currentZ];
for (tileCoordKey in tilesToDraw) {
tile = tilesToDraw[tileCoordKey];
if (tile.getState() == ol.TileState.LOADED) {
renderables.push(tile);
}
}
}
this.renderedTiles_ = renderables;
ol.object.clear(this.clipExtents_);
if (!(tileSource.getOpaque(projection) && layerState.opacity == 1)) {
var clipExtents = this.clipExtents_;
var tileCoord;
for (i = renderables.length - 1; i >= 0; --i) {
tileCoord = renderables[i].getTileCoord();
tileGrid.forEachTileCoordParentTileRange(tileCoord,
function(z, tileRange) {
var tiles = tilesToDrawByZ[z];
if (tiles) {
var key, tile;
for (key in tiles) {
tile = tiles[key];
if (tileRange.contains(tile.getTileCoord()) &&
tile.getState() == ol.TileState.LOADED) {
if (!(key in clipExtents)) {
clipExtents[key] = [];
}
clipExtents[key].push(tileGrid.getTileCoordExtent(tileCoord));
return true;
}
}
}
return false;
}, this, tmpTileRange, tmpExtent);
}
}
this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
this.manageTilePyramid(frameState, tileSource, tileGrid, pixelRatio,
projection, extent, z, tileLayer.getPreload());
this.scheduleExpireCache(frameState, tileSource);
this.updateLogos(frameState, tileSource);
return true;
};
/**
* @inheritDoc
*/
ol.renderer.canvas.TileLayer.prototype.forEachLayerAtPixel = function(
pixel, frameState, callback, thisArg) {
var canvas = this.context_.canvas;
var size = frameState.size;
canvas.width = size[0];
canvas.height = size[1];
this.composeFrame(frameState, this.getLayer().getLayerState(), this.context_);
var imageData = this.context_.getImageData(
pixel[0], pixel[1], 1, 1).data;
if (imageData[3] > 0) {
return callback.call(thisArg, this.getLayer());
} else {
return undefined;
}
};