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Add basic tileLoadFunction example and refine advanced example

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This commit is contained in:
Andreas Hocevar
2018-08-03 08:39:31 +02:00
committed by ahocevar
parent 68ce6de0ca
commit df848d6673
2 changed files with 31 additions and 16 deletions
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39
src/ol/Tile.js
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@@ -9,26 +9,35 @@ import EventType from './events/EventType.js';
/**
* A function that takes an {@link module:ol/Tile} for the tile and a
* `{string}` for the url as arguments.
*
*
* `{string}` for the url as arguments. The default is
* ```js
* source.setTileLoadFunction(function(tile, src) {
* tile.getImage().src = src;
* });
* ```
* function (imageTile, src) {
* For more fine grained control, the load function can use fetch or XMLHttpRequest and involve
* error handling:
*
* ```js
* import TileState from 'ol/TileState';
*
* source.setTileLoadFunction(function(tile, src) {
* var xhr = new XMLHttpRequest();
* xhr.responseType = "blob";
* xhr.addEventListener("loadend", function (evt) {
* xhr.responseType = 'blob';
* xhr.addEventListener('loadend', function (evt) {
* var data = this.response;
* if (typeof data !== "undefined") {
* imageTile.getImage().src = window.URL.createObjectURL(data);
* if (data !== undefined) {
* tile.getImage().src = URL.createObjectURL(data);
* } else {
* tile.setState(TileState.ERROR);
* }
* });
* xhr.addEventListener('error', function () {
* // be sure to set the tile state to ERROR her or the tile will remain in the queue
* imageTile.setState(3);
* tile.setState(TileState.ERROR);
* });
* xhr.open("GET", src);
* xhr.open('GET', src);
* xhr.send();
* }
* });
* ```
*
* @typedef {function(module:ol/Tile, string)} LoadFunction
@@ -212,8 +221,10 @@ class Tile extends EventTarget {
}
/**
* Sets the state of this tile. If you write your own tileLoadFunction,
* it is important to set the state correctly to {@link module:ol/TileState.ERROR} in order for the tile to be removed from the queue.
* Sets the state of this tile. If you write your own {@link module:ol/Tile~LoadFunction tileLoadFunction} ,
* it is important to set the state correctly to {@link module:ol/TileState~ERROR}
* when the tile cannot be loaded. Otherwise the tile cannot be removed from
* the tile queue and will block other requests.
* @param {module:ol/TileState} state State.
* @api
*/