cesium-examples/map/libs/TileLonlatsImageryProvider.js

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/**
* An {@link ImageryProvider} that draws a box around every rendered tile in the tiling scheme, and draws
* a label inside it indicating the X, Y, Level coordinates of the tile. This is mostly useful for
* debugging terrain and imagery rendering problems.
*
* @alias TileLonlatsImageryProvider
* @constructor
*
* @param {Object} [options] Object with the following properties:
* @param {TilingScheme} [options.tilingScheme=new GeographicTilingScheme()] The tiling scheme for which to draw tiles.
* @param {Ellipsoid} [options.ellipsoid] The ellipsoid. If the tilingScheme is specified,
* this parameter is ignored and the tiling scheme's ellipsoid is used instead. If neither
* parameter is specified, the WGS84 ellipsoid is used.
* @param {Color} [options.color=Color.YELLOW] The color to draw the tile box and label.
* @param {Number} [options.tileWidth=256] The width of the tile for level-of-detail selection purposes.
* @param {Number} [options.tileHeight=256] The height of the tile for level-of-detail selection purposes.
*/
var TileLonlatsImageryProvider = function TileLonlatsImageryProvider(options) {
options = Cesium.defaultValue(options, Cesium.defaultValue.EMPTY_OBJECT);
this._tilingScheme = Cesium.defined(options.tilingScheme) ? options.tilingScheme : new Cesium.GeographicTilingScheme({ ellipsoid: options.ellipsoid });
this._color = Cesium.defaultValue(options.color, Cesium.Color.YELLOW);
this._errorEvent = new Cesium.Event();
this._tileWidth = Cesium.defaultValue(options.tileWidth, 256);
this._tileHeight = Cesium.defaultValue(options.tileHeight, 256);
this._readyPromise = Cesium.when.resolve(true);
}
Cesium.defineProperties(TileLonlatsImageryProvider.prototype, {
/**
* Gets the proxy used by this provider.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Proxy}
* @readonly
*/
proxy : {
get : function() {
return undefined;
}
},
/**
* Gets the width of each tile, in pixels. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Number}
* @readonly
*/
tileWidth : {
get : function() {
return this._tileWidth;
}
},
/**
* Gets the height of each tile, in pixels. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Number}
* @readonly
*/
tileHeight: {
get : function() {
return this._tileHeight;
}
},
/**
* Gets the maximum level-of-detail that can be requested. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Number}
* @readonly
*/
maximumLevel : {
get : function() {
return undefined;
}
},
/**
* Gets the minimum level-of-detail that can be requested. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Number}
* @readonly
*/
minimumLevel : {
get : function() {
return undefined;
}
},
/**
* Gets the tiling scheme used by this provider. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {TilingScheme}
* @readonly
*/
tilingScheme : {
get : function() {
return this._tilingScheme;
}
},
/**
* Gets the rectangle, in radians, of the imagery provided by this instance. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Rectangle}
* @readonly
*/
rectangle : {
get : function() {
return this._tilingScheme.rectangle;
}
},
/**
* Gets the tile discard policy. If not undefined, the discard policy is responsible
* for filtering out "missing" tiles via its shouldDiscardImage function. If this function
* returns undefined, no tiles are filtered. This function should
* not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {TileDiscardPolicy}
* @readonly
*/
tileDiscardPolicy : {
get : function() {
return undefined;
}
},
/**
* Gets an event that is raised when the imagery provider encounters an asynchronous error. By subscribing
* to the event, you will be notified of the error and can potentially recover from it. Event listeners
* are passed an instance of {@link TileProviderError}.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Event}
* @readonly
*/
errorEvent : {
get : function() {
return this._errorEvent;
}
},
/**
* Gets a value indicating whether or not the provider is ready for use.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Boolean}
* @readonly
*/
ready : {
get : function() {
return true;
}
},
/**
* Gets a promise that resolves to true when the provider is ready for use.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Promise.<Boolean>}
* @readonly
*/
readyPromise : {
get : function() {
return this._readyPromise;
}
},
/**
* Gets the credit to display when this imagery provider is active. Typically this is used to credit
* the source of the imagery. This function should not be called before {@link TileCoordinatesImageryProvider#ready} returns true.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Credit}
* @readonly
*/
credit : {
get : function() {
return undefined;
}
},
/**
* Gets a value indicating whether or not the images provided by this imagery provider
* include an alpha channel. If this property is false, an alpha channel, if present, will
* be ignored. If this property is true, any images without an alpha channel will be treated
* as if their alpha is 1.0 everywhere. Setting this property to false reduces memory usage
* and texture upload time.
* @memberof TileCoordinatesImageryProvider.prototype
* @type {Boolean}
* @readonly
*/
hasAlphaChannel : {
get : function() {
return true;
}
}
});
/**
* Gets the credits to be displayed when a given tile is displayed.
*
* @param {Number} x The tile X coordinate.
* @param {Number} y The tile Y coordinate.
* @param {Number} level The tile level;
* @returns {Credit[]} The credits to be displayed when the tile is displayed.
*
* @exception {DeveloperError} <code>getTileCredits</code> must not be called before the imagery provider is ready.
*/
TileLonlatsImageryProvider.prototype.getTileCredits = function (x, y, level) {
return undefined;
};
/**
* Requests the image for a given tile. This function should
* not be called before {@link TileLonlatsImageryProvider#ready} returns true.
*
* @param {Number} x The tile X coordinate.
* @param {Number} y The tile Y coordinate.
* @param {Number} level The tile level.
* @param {Request} [request] The request object. Intended for internal use only.
* @returns {Promise.<Image|Canvas>|undefined} A promise for the image that will resolve when the image is available, or
* undefined if there are too many active requests to the server, and the request
* should be retried later. The resolved image may be either an
* Image or a Canvas DOM object.
*/
TileLonlatsImageryProvider.prototype.requestImage = function (x, y, level, request) {
var canvas = document.createElement('canvas');
canvas.width = 256;
canvas.height = 256;
var context = canvas.getContext('2d');
var cssColor = this._color.toCssColorString();
context.strokeStyle = cssColor;
context.lineWidth = 2;
context.strokeRect(1, 1, 255, 255);
/*
可以使用GeographicTilingScheme的tileXYToNativeRectangle接口获取对应关系不需要自己算
*/
var interval = 180.0 / Math.pow(2, level);
var lon = (x + 0.5) * interval-180;
var lat = 90 - (y + 0.5) * interval;
//var label = 'L-' + level + 'X-' + x + 'Y-' + y;
var labelLevel = '';
var labelLon = '';
var labelLat = '';
if (lon > 0) {
if (lat > 0) {
//label = 'L' + level + 'E' + lon + 'N' + lat;
labelLevel = 'L' + level;
labelLon = 'E' + lon;
labelLat = 'N' + lat;
} else {
//label = 'L' + level + 'E' + lon + 'S' + (-lat);
labelLevel = 'L' + level;
labelLon = 'E' + lon;
labelLat = 'N' + (-lat);
}
} else {
if (lat > 0) {
//label = 'L' + level + 'W' + (-lon) + 'N' + lat;
labelLevel = 'L' + level;
labelLon = 'E' + (-lon);
labelLat = 'N' + lat;
} else {
//label = 'L' + level + 'W' + (-lon) + 'S' + (-lat);
labelLevel = 'L' + level;
labelLon = 'E' + (-lon);
labelLat = 'N' + (-lat);
}
}
context.textAlign = 'center';
context.fillStyle = cssColor;
if (level > 10) {
context.font = 'bold 16px Arial';
context.fillText(labelLevel, 124, 100);
context.fillText(labelLon, 124, 124);
context.fillText(labelLat, 124, 148);
} else {
context.font = 'bold 25px Arial';
context.fillText(labelLevel, 124, 94);
context.fillText(labelLon, 124, 124);
context.fillText(labelLat, 124, 154);
}
//context.textAlign = 'center';
//context.fillStyle = 'black';//绘制阴影效果
//context.fillText(label, 127, 127);
//context.fillStyle = cssColor;
//context.fillText(label, 124, 24);
return canvas;
};
/**
* Picking features is not currently supported by this imagery provider, so this function simply returns
* undefined.
*
* @param {Number} x The tile X coordinate.
* @param {Number} y The tile Y coordinate.
* @param {Number} level The tile level.
* @param {Number} longitude The longitude at which to pick features.
* @param {Number} latitude The latitude at which to pick features.
* @return {Promise.<ImageryLayerFeatureInfo[]>|undefined} A promise for the picked features that will resolve when the asynchronous
* picking completes. The resolved value is an array of {@link ImageryLayerFeatureInfo}
* instances. The array may be empty if no features are found at the given location.
* It may also be undefined if picking is not supported.
*/
TileLonlatsImageryProvider.prototype.pickFeatures = function (x, y, level, longitude, latitude) {
return undefined;
};