Extension:Graph/zh

標籤將JSON格式的數據轉換、呈現為可視的Vega圖表，例如：長條圖、圓餅圖、時間線、直方圖...（更多範例）.

基本信息
圖表擴展允許基於Vega的圖表被加入至Wiki頁面中. 圖表可以是靜態或互動式的.

插入圖表最簡單的方法就是使用預先製作的模板，如利用製作長條圖. 這些模板隱藏了所有Vega複雜的部份. 開發者可藉由圖表沙盒開發圖表. （除了JSON格式，圖表沙盒也支援維基語法）

外部链接

 * - 在Wiki中使用圖表的建議.
 * - 說明如何從頭開始構建複雜的互動式圖表.
 * - 一些範例和使用技巧.
 * TechTalk 影片 - WMF技術講座上圖表擴展的討論，包括Lyra編輯器很棒的範例. （實驗室也有安裝）
 * Vega 未來功能. (Jeffrey Heer的專題演講)
 * Vega for devs - best place of all Vega resources
 * Video introduction into interactive Vega
 * Video introduction into interactive Vega

Charts examples
See for many samples and usage tricks.

外部数据
HTTP(S) protocol cannot be used to get data for the graph. Instead, use one of the custom wiki protocols like,  , and others.

Graphoid service and Graph extension use  setting to control how these protocols are resolved:

Known bugs & limitations

 * Graph extension bugs
 * Graphoid service bugs
 * Fails to implement ISO 8601 timescales so only Gregorian calendars can be used in timelines

Internals
When parsing, the Graph extension expands all template parameters/expressions, and stores the complete graph definitions in the  page property, using graph hashes for IDs. This means you can easily locate a wiki's graphs with either Special:PageWithProps or [//www.mediawiki.org/w/api.php?action=query&list=pageswithprop&continue=&formatversion=2&pwppropname=graph_specs the action API].

The graph extension adds HTML to the page where graphs should go, a containing an  tag. Sample:

The tag's   attribute points to the #Graphoid service, which provides a [//www.mediawiki.org/api/rest_v1/page/graph/png/Extension%3AGraph%2FDemo/1686336/d243aa924db2f82926e0f317217fcce591fe8cd4.png static image of the graph].

If the Graph extension is configured for interactivity, and if the client browser has JavaScript enabled and is not a legacy browser to which ResourceLoader does not ship JavaScript, then the client browser renders graphs on the fly. The Graph extension adds an  ResourceLoader JavaScript module to the page that includes the Vega library, and puts the JSON of graph definitions into a JavaScript   variable named. Once the client has loaded this module, the Vega JavaScript library populates each with an HTML canvas and draws the graph in it, replacing the static image. , Wikimedia wikis only enable this interactive rendering for edit preview.

You can configure the Graph extension to always use just the tag, and not add the Vega libraries or graph definition JSON. This mode will not work during editing, since  do not get updated until after the save. Once saved, the Graphoid service will be able to access the new graph definition via the action API.

Security Features
can be configured to disallow referencing untrusted data sources (e.g. Wikimedia only allows data from the Wikimedia sites). It can also send extra headers whenever accessing external data, e.g.  header that MediaWiki uses to prevent CSRF attacks.

License
Vega library is distributed under a modified BSD license acceptable under for us to use.

This appears to be a copy of the BSD license, with some minor (acceptable) modifications. It's not a problem for us to use it, although ideally they would not make changes like this to the license. It's better if people do not make these changes to their license, to avoid confusion (like this) about whether the license is safe for open-source use.

wgGraphIsTrusted
If  (default), passes Treat-as-Untrusted:1 header with all graph data requests

wgGraphImgServiceUrl
A format string to form a backend service request URL for the &lt;img> tag. For example:

Would produce this URL:

//graphoid.wikimedia.org/mediawiki.org/v1/png/Extension:Graph/0/be66c7016b9de3188ef6a585950f10dc83239837.png /{domain}/v1/png/{title}/{revid}/{hash}.png

Parameters will be supplied in this order: 1=server, 2=title, 3=revid, 4=graph-hash-id. All parameters will be escaped with rawurlencode. If the value is  (default), no urls will be generated

wgGraphUrlBlacklist variable has been removed in 787d64a11 (7 Dec 2015), wgGraphDataDomains has been removed in e0813f85a (28 Jan 2016). Use a wgGraphAllowedDomains instead.

wgGraphUserServiceAlways variable has been removed in b735f63ff4b (30 Sep 2015).

Enabling Graph namespace
To store graph definitions as standalone pages in their own namespace, configure JsonConfig.

Graphoid service
Graphoid is a node.js  service that converts a graph definition into a static PNG image using the same Vega library code that runs in advanced browsers. The service is available on the Wikimedia cluster at graphoid.wikimedia.org.

You can install it yourself:

The service URLs contain the domain of the page (for example mediawiki.org), service version (v1), the title of the page with the graph (PageTitle), revision ID of the page (12345, but could be 0 for current), and a hash ID of the graph itself (also used in HTML page to identify graph definition), for example:

http://localhost:6927/mediawiki.org/v1/PageTitle/12345/a64b022a8fa5b7fc5e40a2c95cd0a114b2ae1174.png http://graphoid.wikimedia.org/mediawiki.org/v1/png/Extension:Graph/0/be66c7016b9de3188ef6a585950f10dc83239837.png You configure the Graph extension to use the Graphoid service in LocalSettings.php with a line like



You can further configure the service via its config file.

VisualEditor module
Since summer 2015, the Graph extension also comes with a module (ext.graph.VisualEditor) which enables graph editing within VisualEditor.

This module was a result of a Google Summer of Code 2015 project. See T89287 for more details.

This module allows users to see graphs within VisualEditor, as opposed to alien extension nodes. Furthermore, users can open up a dialog to edit a graph's type, data and padding. The UI also offers a way to edit a graph's raw JSON specification within VE without having to switch to the classic wikitext editor, in case more advanced users want to tweak settings not supported by the UI.

This first step serves as a stepping stone for many possibilities with graph editing within VisualEditor, and there are a lot of ways in which the module can be improved and expanded.