Merge pull request #8177 from gberaudo/remove_closure_related_documentation
Remove documentation related to the closure compiler
This commit is contained in:
Andreas Hocevar
GitHub
@@ -19,8 +19,6 @@ Use one of the following methods to use OpenLayers in your project:
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* If you just want to add a `<script>` tag to test things out, you can link directly to one of the full builds from [cdnjs](https://cdnjs.com/libraries/openlayers) (not recommended for production)
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* For use with Closure Library (rare), install the [`openlayers` package](https://npmjs.com/package/openlayers) and read the [tutorial](http://openlayers.org/en/latest/doc/tutorials/closure.html).
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## Supported Browsers
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OpenLayers runs on all modern browsers that support [HTML5](https://html.spec.whatwg.org/multipage/) and [ECMAScript 5](http://www.ecma-international.org/ecma-262/5.1/). This includes Chrome, Firefox, Safari and Edge. For older browsers and platforms like Internet Explorer (down to version 9) and Android 4.x, [polyfills](http://polyfill.io) for `requestAnimationFrame` and `Element.prototype.classList` are required, and using the KML format requires a polyfill for `URL`.
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37
doc/faq.md
37
doc/faq.md
@@ -21,9 +21,6 @@ Table of contents:
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* [Why aren't there any features in my source?](#why-aren-t-there-any-features-in-my-source-)
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* [How do I force a re-render of the map?](#how-do-i-force-a-re-render-of-the-map-)
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* [Why are my features not found?](#why-are-my-features-not-found-)
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* [How do I create a custom build of OpenLayers?](#how-do-i-create-a-custom-build-of-openlayers-)
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* [Do I need to write my own code using Closure library?](#do-i-need-to-write-my-own-code-using-closure-library-)
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* [Do I need to compress my code with Closure compiler?](#do-i-need-to-compress-my-code-with-closure-compiler-)
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## What projection is OpenLayers using?
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@@ -335,37 +332,3 @@ var vectorLayer = new ol.layer.Vector({
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```
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The recommended value is the size of the largest symbol, line width or label.
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## How do I create a custom build of OpenLayers?
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Please refer to the [official create custom builds tutorial](tutorials/custom-builds.html)
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which explains how to create a custom build of OpenLayers with just those parts
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included that you want.
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## Do I need to write my own code using Closure library?
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OpenLayers is built on top of the [Google Closure JavaScript
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library](https://developers.google.com/closure/library/), but this
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does not mean that you must use that library in your application code.
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OpenLayers should play well with all sorts of JavaScript libraries out there,
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and you are in no way forced to use a specific one. Choose one that looks
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right for you.
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## Do I need to compress my code with Closure compiler?
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No, you don't need to do compress your code with the [Google Closure
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compiler](https://developers.google.com/closure/compiler/).
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It may be a good choice though, because when your application code and the
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OpenLayers source code is compiled together using closure compiler, the
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resulting build will most probably be the smallest in terms of byte-size. For
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more details refer to the
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[compile application and OpenLayers together tutorial](tutorials/closure.html).
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If you don't want to use the closure compiler, or you can't, you are not at all
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forced to use it.
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@@ -1,295 +0,0 @@
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---
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title: Compiling Application with Closure Compiler
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layout: doc.hbs
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---
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# Compiling Application with Closure Compiler
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**Note**: When building an application with dependencies that are available as [npm](https://npmjs.com/) packages, it will probably be easier to use the [ol](https://npmjs.com/package/ol) package and follow the instructions there.
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The OpenLayers code uses the Closure Library, and it is compiled with the
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Closure Compiler. Using OpenLayers in an application does not require using
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Closure. But using Closure in an OpenLayers application is possible. And this
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is what this tutorial is about.
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When you want to include OpenLayers as separate script without bundling with your application, follow the [Creating custom builds](./custom-builds.html) tutorial instead.
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This tutorial will teach you how to set up an OpenLayers application based on
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the [`closure-util`](https://github.com/openlayers/closure-util) node package,
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which provides utilities for working with Closure. Using `closure-util` is one
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way to use Closure in a web application, but there are others. This tutorial
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just covers the "`closure-util`" way.
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The `closure-util` documentation is available on the [`closure-util` readme
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page](https://github.com/openlayers/closure-util/blob/master/readme.md). You
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don't need to read the `closure-util` documentation to follow this tutorial,
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but it's available in `closure-util`'s [readme
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file](https://github.com/openlayers/closure-util/blob/master/readme.md) if you
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need it.
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Also, the sample application built in this tutorial is
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[available](https://github.com/openlayers/openlayers-closure-application) on
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GitHub.
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## Advantages of using Closure
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This tutorial will show you how to use the Closure Compiler to compile an
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application and OpenLayers together. Compiling the application code together
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with the OpenLayers code has a number of advantages.
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First of all, it allows you to only "pay" for the OpenLayers code your
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application uses, as the compiler will exclude the OpenLayers code that the
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application doesn't use. And there is no need to write and maintain a list of
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"exports", which is necessary when creating custom builds of OpenLayers.
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Also, compiling the application and OpenLayers together allows using
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OpenLayers functions and objects that are not part of the official OpenLayers
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3 API. Using non-API functions and objects may be risky, but it is mitigated by
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the fact that the compiler will complain if you use functions or objects
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that are not in OpenLayers anymore.
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## Setting up the Application
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First, create a directory for the application. We will name that directory
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`openlayers-closure-application` in this tutorial.
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$ mkdir openlayers-closure-application
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Now change to that directory:
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$ cd openlayers-closure-application
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Our application will be a `node` application, and the `openlayers` and
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`closure-util` node packages will be downloaded from the node package registry
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using the `npm` command line tool.
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So we're going to create a `package.json` file for the application, which every
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node application includes. This file basically includes metadata for the
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application.
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Create the application's `package.json` file:
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$ npm init
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You can pretty much use the default answers to the questions `npm init` asks
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you.
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Now install OpenLayers using:
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$ npm install openlayers --save
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The `--save` flag persists the `openlayers` dependency in the application's
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`package.json` file. You can edit `package.json` to verify that the dependency
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was added.
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`closure-util` is a dependency of the `openlayers` package, so it should have
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been installed with `openlayers`. Use the following to verify that
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`closure-util` is installed:
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$ ./node_modules/openlayers/node_modules/.bin/closure-util
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command argument is required
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Usage: node closure-util <command> [options]
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command
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update-compiler Update the Compiler
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update-library Update the Library
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update Update both the Library and the Compiler
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build Build with Closure Compiler
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serve Start the development server
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Options:
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-l LEVEL, --loglevel LEVEL Log level [info]
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## Create an OpenLayers map
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You're now going to create a JavaScript file that creates an OpenLayers map.
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This is the file that we will define the application's entry point.
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First of all create an `src` directory at the root of the application:
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$ mkdir src
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Now add a file `main.js` to `src`, with the following content:
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```js
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goog.provide('app');
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goog.require('ol.Map');
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goog.require('ol.View');
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goog.require('ol.layer.Tile');
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goog.require('ol.source.OSM');
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/**
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* @type {ol.PluggableMap}
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*/
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app.map = new ol.Map({
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target: 'map',
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layers: [
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new ol.layer.Tile({
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source: new ol.source.OSM()
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})
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],
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view: new ol.View({
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center: [0, 0],
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zoom: 4
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})
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});
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```
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`goog.provide('app')` creates the namespace `app` for the application. The
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`goog.require` statements that follow define the OpenLayers constructors and
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namespaces that the application uses. The rest of the code just creates the
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OpenLayers map as you would do in any OpenLayers application.
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## Compiling the Application
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We're now going to compile the application and OpenLayers together, using the
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Closure Compiler and `closure-util`. For this we need to create a JSON config
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file, that we will then pass as an input file to the `closure-util` command.
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The minimum config file looks like this:
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```json
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{
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"lib": [
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"node_modules/openlayers/src/**/*.js",
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"node_modules/openlayers/build/ol.ext/**/*.js",
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"src/**/*.js"
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],
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"compile": {
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"closure_entry_point": "app",
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"externs": [
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"node_modules/openlayers/externs/bingmaps.js",
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"node_modules/openlayers/externs/cartodb.js",
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"node_modules/openlayers/externs/closure-compiler.js",
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"node_modules/openlayers/externs/esrijson.js",
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"node_modules/openlayers/externs/geojson.js",
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"node_modules/openlayers/externs/proj4js.js",
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"node_modules/openlayers/externs/tilejson.js",
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"node_modules/openlayers/externs/topojson.js"
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],
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"define": [
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"ol.ENABLE_WEBGL=false"
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],
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"extra_annotation_name": [
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"api", "observable"
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],
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"rewrite_polyfills": "false",
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"compilation_level": "ADVANCED",
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"warning_level": "VERBOSE",
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"output_wrapper": "(function(){%output%})();",
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"use_types_for_optimization": true
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}
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}
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```
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Create a `config.json` file with the above content at the root of the
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application directory.
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We can now use `closure-util` to compile the code:
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$ ./node_modules/openlayers/node_modules/.bin/closure-util build config.json app.js
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The resulting `app.js` file, which you can view in your editor if you're
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curious, includes a minified version of the application code (`main.js`), and
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the OpenLayers code that the application code uses.
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Here is a version of `config.json` with more compilation checks enabled:
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```json
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{
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"lib": [
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"node_modules/openlayers/src/**/*.js",
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"node_modules/openlayers/build/ol.ext/**/*.js",
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"src/**/*.js"
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],
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"compile": {
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"closure_entry_point": "app",
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"externs": [
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"node_modules/openlayers/externs/bingmaps.js",
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"node_modules/openlayers/externs/cartodb.js",
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"node_modules/openlayers/externs/closure-compiler.js",
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"node_modules/openlayers/externs/esrijson.js",
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"node_modules/openlayers/externs/geojson.js",
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"node_modules/openlayers/externs/proj4js.js",
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"node_modules/openlayers/externs/tilejson.js",
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"node_modules/openlayers/externs/topojson.js"
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],
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"define": [
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"ol.ENABLE_WEBGL=false"
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],
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"jscomp_error": [
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"*"
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],
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"jscomp_off": [
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"unknownDefines",
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"lintChecks",
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"analyzerChecks"
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],
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"extra_annotation_name": [
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"api", "observable"
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],
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"compilation_level": "ADVANCED",
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"warning_level": "VERBOSE",
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"output_wrapper": "(function(){%output%})();",
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"use_types_for_optimization": true
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}
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}
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```
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## Create an HTML file for the Application
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You can now go ahead and create a simple HTML for the application. Create
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a `index.html` file with the following content at the root the application
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directory:
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```html
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<!doctype html>
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<meta http-equiv="X-UA-Compatible" content="chrome=1">
|
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<meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">
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<link rel="stylesheet" href="node_modules/openlayers/css/ol.css" type="text/css">
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<title>Simple example</title>
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<style>
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#map {
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width: 600px;
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height: 400px;
|
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}
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</style>
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</head>
|
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<body>
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<div id="map"></div>
|
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<script src="app.js" type="text/javascript"></script>
|
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</body>
|
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</html>
|
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```
|
||||
|
||||
Note that the page includes a `script` tag referencing the `app.js` file,
|
||||
which is the file resulting from the compilation.
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You are done!
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## Run Application in Debug Mode
|
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|
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As a bonus, we're going to show how to use `closure-util` to run the
|
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application in "debug" mode, where the original application and OpenLayers
|
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scripts are loaded one by one in the page.
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|
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Start the `closure-util` development server:
|
||||
|
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$ ./node_modules/openlayers/node_modules/.bin/closure-util serve config.json
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||||
|
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Now change the `script` tag to the following in the `index.html` file:
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||||
|
||||
```html
|
||||
<script src="@?main=src/main.js" type="text/javascript"></script>
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```
|
||||
|
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Reload the page in your browser and you should see that scripts are now loaded
|
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individually, making debugging much easier.
|
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@@ -1,231 +0,0 @@
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---
|
||||
title: Custom builds
|
||||
layout: doc.hbs
|
||||
---
|
||||
|
||||
# Creating custom builds
|
||||
|
||||
OpenLayers is a big library providing a lot of functionality. So it is unlikely that an application will need and use all the functionality OpenLayers provides. This is why creating application-specific OpenLayers builds, with just the functionality your application needs, is often a good idea.
|
||||
|
||||
An alternative to creating custom builds is to compile your application code together with OpenLayers. See the [Compiling Application with Closure Compiler](closure.html) tutorial for more information.
|
||||
|
||||
This particular tutorial explains how to create custom builds of OpenLayers.
|
||||
|
||||
## Requirements
|
||||
|
||||
OpenLayers's build tools use Node and Java, so you need to have Node and Java installed on your machine. You can run `node --version` and `java -version` to test that Node and Java are installed, respectively. See [developing guide](https://github.com/openlayers/openlayers/blob/master/DEVELOPING.md) for minimum version numbers required.
|
||||
|
||||
## Download OpenLayers
|
||||
|
||||
Obviously, creating a custom build requires the OpenLayers source and specific build scripts.
|
||||
|
||||
To get the OpenLayers source and the build scripts you can clone the openlayers [repository](https://github.com/openlayers/openlayers), or you can download one of the release archives. You can also download the `openlayers` Node package from the Node package registry, using NPM (the Node Package Manager). This is the method we are going to use in this tutorial.
|
||||
|
||||
Create a directory:
|
||||
|
||||
$ mkdir openlayers
|
||||
|
||||
Download the OpenLayers distribution using NPM:
|
||||
|
||||
$ npm install openlayers
|
||||
|
||||
This will download the latest stable version of OpenLayers, and install it under `node_modules`. You can list the content of `node_modules` to verify that it effectively contains a directory named "openlayers".
|
||||
|
||||
The Node packages onto which the `openlayers` package depends are installed under `node_modules/openlayers/node_modules`. That directory should, for example, include `closure-util`, which is the utility library OpenLayers uses for Closure.
|
||||
|
||||
You should now have everything you need to create custom builds of OpenLayers!
|
||||
|
||||
## Create a build configuration file
|
||||
|
||||
Creating a custom build requires writing a build configuration file. The format of build configuration files is JSON. Here is a simple example of a build configuration file:
|
||||
|
||||
```json
|
||||
{
|
||||
"exports": [
|
||||
"ol.Map",
|
||||
"ol.View",
|
||||
"ol.control.defaults",
|
||||
"ol.layer.Tile",
|
||||
"ol.source.OSM"
|
||||
],
|
||||
"compile": {
|
||||
"externs": [
|
||||
"externs/bingmaps.js",
|
||||
"externs/cartodb.js",
|
||||
"externs/closure-compiler.js",
|
||||
"externs/esrijson.js",
|
||||
"externs/geojson.js",
|
||||
"externs/proj4js.js",
|
||||
"externs/tilejson.js",
|
||||
"externs/topojson.js"
|
||||
],
|
||||
"extra_annotation_name": [
|
||||
"api", "observable"
|
||||
],
|
||||
"compilation_level": "ADVANCED",
|
||||
"manage_closure_dependencies": true,
|
||||
"rewrite_polyfills": false
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Create a file named `ol-custom.json` with that content, and save it under the `node_modules/openlayers/build` directory. (You can save it to any location really.)
|
||||
|
||||
The most relevant part of this configuration object is the `"exports"` array. This array declares the functions/constructors you use in your JavaScript code. For example, the above configuration file is what you'd use for the following JavaScript code:
|
||||
|
||||
```js
|
||||
var map = new ol.Map({
|
||||
target: 'map',
|
||||
layers: [
|
||||
new ol.layer.Tile({
|
||||
source: new ol.source.OSM()
|
||||
})
|
||||
],
|
||||
controls: ol.control.defaults({
|
||||
attributionOptions: {
|
||||
collapsible: false
|
||||
}
|
||||
}),
|
||||
view: new ol.View({
|
||||
center: [0, 0],
|
||||
zoom: 4
|
||||
})
|
||||
});
|
||||
```
|
||||
|
||||
Note that this JavaScript code corresponds to OpenLayers's [`simple`](https://openlayers.org/en/master/examples/simple.html) example.
|
||||
|
||||
You are now ready to create your first OpenLayers build. Use the following command to create the build:
|
||||
|
||||
$ cd node_modules/openlayers
|
||||
$ node tasks/build.js build/ol-custom.json build/ol-custom.js
|
||||
|
||||
The build command may take some time, but it should end with an output in the console such as the following:
|
||||
|
||||
info ol Parsing dependencies
|
||||
info ol Compiling 364 sources
|
||||
|
||||
The build command should have created an `ol-custom.js` file in the `node_modules/openlayers/build` directory. You can verify that the file was created. You can even open it in your editor if you're curious.
|
||||
|
||||
As a test, you can use the following HTML file to verify that your custom build works as expected:
|
||||
|
||||
```html
|
||||
<!DOCTYPE html>
|
||||
<html>
|
||||
<head>
|
||||
<meta charset="utf-8" />
|
||||
<title>OpenLayers example</title>
|
||||
<link rel="stylesheet" href="node_modules/openlayers/css/ol.css" />
|
||||
<style>
|
||||
#map {
|
||||
width: 600px;
|
||||
height: 400px;
|
||||
}
|
||||
</style>
|
||||
</head>
|
||||
<body>
|
||||
<div id="map"></div>
|
||||
<script src="node_modules/openlayers/build/ol-custom.js"></script>
|
||||
<script>
|
||||
var map = new ol.Map({
|
||||
target: 'map',
|
||||
layers: [
|
||||
new ol.layer.Tile({
|
||||
source: new ol.source.OSM()
|
||||
})
|
||||
],
|
||||
view: new ol.View({
|
||||
center: [0, 0],
|
||||
zoom: 4
|
||||
})
|
||||
});
|
||||
</script>
|
||||
</body>
|
||||
</html>
|
||||
```
|
||||
|
||||
## More on the config file
|
||||
|
||||
### `define`'s
|
||||
|
||||
Closure allows you to define constants that can be set at compile time. The OpenLayers code defines several such values.
|
||||
|
||||
Setting some of these to `false` means that the portions of the code relating to this setting become "dead", i.e. are never executed. As Closure Compiler's `ADVANCED` mode removes dead code, this makes the size of the advanced compiled file smaller.
|
||||
|
||||
You might have noticed that the build file you've just created is considerably smaller than the full build, but it can be reduced further. This is because both renderers and other optional code are included by default. We only need one renderer, and we do not use the optional code, so can exclude what we don't use by setting properties with `define`s. So add a define section to the config above:
|
||||
```
|
||||
"define": [
|
||||
"ol.ENABLE_WEBGL=false",
|
||||
"ol.ENABLE_PROJ4JS=false",
|
||||
"ol.ENABLE_RASTER_REPROJECTION=false"
|
||||
],
|
||||
```
|
||||
|
||||
and re-run the build script. The build size should now be smaller.
|
||||
|
||||
### Externs
|
||||
|
||||
The Closure documentation explains that "externs" are for external names used in the code being compiled. The compiler includes externs for built-ins such as `document`. The `externs` directory of the OpenLayers code includes files for all those used in some part of the library. For example, if you use Bing Maps, you should include the Bing externs file in the `externs` section of the config file.
|
||||
|
||||
### Other compiler options
|
||||
|
||||
There are a couple of other compiler options in the config file above. `manage_closure_dependencies` and `rewrite_polyfills` should always be used.
|
||||
|
||||
You can specify any of the other compiler options here as needed, such as the renaming reports, output manifest, or source maps. There is a full list of available options in [closure-util](https://github.com/openlayers/closure-util/blob/master/compiler-options.txt).
|
||||
|
||||
Note that `build.js` currently requires you to enter an output file and will write the output from the compiler to it; it does not use the `js_output_file` compiler option. If you specify this in the config file, there will be no compiler output, so `build.js`'s output file will be empty.
|
||||
|
||||
## A more complicated example
|
||||
|
||||
Now let's try a more complicated example: [`heatmaps-earthquakes`](https://openlayers.org/en/master/examples/heatmap-earthquakes.html). The build configuration file looks like this:
|
||||
|
||||
```json
|
||||
{
|
||||
"exports": [
|
||||
"ol.layer.Heatmap",
|
||||
"ol.source.Vector",
|
||||
"ol.format.KML",
|
||||
"ol.layer.Heatmap#getSource",
|
||||
"ol.source.Vector#on",
|
||||
"ol.source.Vector.Event#feature",
|
||||
"ol.Feature#get",
|
||||
"ol.Feature#set",
|
||||
"ol.layer.Tile",
|
||||
"ol.source.Stamen",
|
||||
"ol.Map",
|
||||
"ol.View",
|
||||
"ol.layer.Heatmap#setRadius",
|
||||
"ol.layer.Heatmap#setBlur"
|
||||
],
|
||||
"compile": {
|
||||
"externs": [
|
||||
"externs/bingmaps.js",
|
||||
"externs/cartodb.js",
|
||||
"externs/closure-compiler.js",
|
||||
"externs/esrijson.js",
|
||||
"externs/geojson.js",
|
||||
"externs/proj4js.js",
|
||||
"externs/tilejson.js",
|
||||
"externs/topojson.js"
|
||||
],
|
||||
"define": [
|
||||
"ol.ENABLE_WEBGL=false",
|
||||
"ol.ENABLE_PROJ4JS=false",
|
||||
"ol.ENABLE_RASTER_REPROJECTION=false"
|
||||
],
|
||||
"compilation_level": "ADVANCED",
|
||||
"manage_closure_dependencies": true,
|
||||
"rewrite_polyfills": false
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
The exports are given here in the order in which they occur in the `heatmaps-earthquakes` example's JavaScript code. In this example we not only use the `ol.` functions and constructors, but also `prototype` methods where the `ol` namespace is not directly used. In the code, we have for example `vector.getSource().on()`. This means we are using the `getSource` method of `layer.Heatmap` and the `on` method of `source.KML`, so this is what has to be exported. Similarly, `event.feature.get()` means we are using the `feature` property of `source.Vector.Event` and the `get` method of `Feature`. If any of these names are left out, the compile will complete successfully, but the missing names will be obfuscated and you will get a 'property undefined' error when you try and run the script.
|
||||
|
||||
## Maintaining the code
|
||||
|
||||
If you installed OpenLayers from the Node package, you can use `npm` to upgrade to the latest version. If you cloned the Github repo, simply pulling in the latest code may not be enough, as some of the packages used, for example, the compiler, may need upgrading too. Do this by using `npm install` rather than `npm update`.
|
||||
|
||||
## Conclusion
|
||||
|
||||
This tutorial should have given you the information you need to create custom builds, i.e. builds tailored to your application. See the [tasks readme](https://github.com/openlayers/openlayers/tree/master/tasks/readme.md) for more information on the build scripts and the properties you can use in the build configuration file.
|
||||
@@ -9,5 +9,4 @@ layout: doc.hbs
|
||||
* [Basic Concepts](concepts.html)
|
||||
* [Create Custom Builds](custom-builds.html)
|
||||
* [Bundle Application and OpenLayers using Browserify](browserify.html)
|
||||
* [Compile Application and OpenLayers together](closure.html)
|
||||
* [Raster Reprojection](raster-reprojection.html)
|
||||
|
||||
@@ -12,9 +12,6 @@ The initial release aims to support much of the functionality provided by versio
|
||||
|
||||
It is also designed such that major new features, such as displaying 3D maps, or using WebGL to quickly display large vector data sets, can be added in later releases.
|
||||
|
||||
## Google Closure
|
||||
OpenLayers was written in a way so it can be compiled with [__Closure Compiler__](https://developers.google.com/closure/compiler/). Its 'advanced' compilation mode offers a level of compression that exceeds anything else available.
|
||||
|
||||
## Public API
|
||||
Using the advanced optimizations of the Closure Compiler means that properties and methods are renamed – `longMeaningfulName` might become `xB` – and so are effectively unusable in applications using the library. To be usable, they have to be explicitly `exported`. This means the exported names, those not renamed, effectively become the public API of the library. These __exportable__ properties and methods are marked in the source, and documented in the [API docs](../../apidoc). This is the officially supported API of the library. A build containing all these exportable names is known as a __full build__. A hosted version of this is available, which can be used by any application.
|
||||
|
||||
|
||||
Reference in New Issue
Block a user