Extension:Graph/zh

Graph扩展允许标签以JSON格式描述数据可视化内容，例如条形图，饼图，时间线和直方图（示范），该JSON格式呈现Vega的图表.



基本信息
圖表擴展允許将基於Vega的圖表加入至Wiki頁面中. 圖表可以是交互式的.

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） The extension integrates with VisualEditor, providing a simple tool/wizard which generates basic graphs, by entering values directly to the editor.



外部链接

 * Vega2文档 - 在nyurik/vega/wiki恢复了Vega2的文档页面.
 * - 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 - 所有Vega資源的聚集地.
 * 介紹Vega互動式圖表的影片
 * 介紹Vega互動式圖表的影片

Additional config setup
If you are looking to replicate a production environment like en.wiki you will need to complete the following steps:


 * Install, and , and enable SVG uploads
 * If you use vagrant, you can use
 * Import mediawiki.org's Module:Graph, Module:Graph/doc, and Template:Nowrap/styles.css (export link)
 * Import enwiki's Module:Chart and Module:Chart/Default colors (export link)
 * Import the file File:Circle_frame.svg

Debugging graphs and porting graphs from Vega 2 to Vega 5
A sandbox is provided at Special:GraphSandbox that works similar to the Vega graph editor. The MediaWiki tool includes compatibility code that maps older Vega schemas to the currently enabled version. Inserting an old schema in the main text area will print a modified and modernized schema underneath the graph where possible.

Similar to vega.github.io/editor, the Vega object can be inspected via the  JavaScript global. See Vega's debugging guide on how to use it.

Migrating schemas from older Vega versions
Previously Graph supported Vega 2. You can paste the JSON of graphs in http://vega.github.io/vega-editor/?mode=vega to see how they previously rendered for comparison with Vega 5.

Special:GraphSandbox (for latest code see the beta cluster version of the sandbox) can be used to map older schemas to new schemas. Copy the old schema into the main textarea and the updated schema will appear in the text area below the graph. Copy the new schema into your code.



圖表範例
參考獲得更多範例及使用技巧.

User defined fallback
When using client side rendering, it is possible to use Wikimedia Commons to provide a static fallback image to  users. This is a temporary solution until a new service is put in place to provide server side rendering.

The user must first upload the static graph to Wikimedia Commons.

Fallback images have two variables  and.

relates to a Wikimedia Commons filename.

is the fallback images width in pixels.

These variables are pass through the graph in the following way:

Where lua modules are used such as Module:Graph then these variables can be provided via the tag function. If were adapted, it would look like this:

It would then be utilised in a template in the following manner:

If a fallbackWidth isn't provided but an image is defined then the extension will derive the width from the provided graph width. The reason for this is there is frequently a difference in the rendered image width and the actual image width.



外部数据
HTTPS無法為圖表取得數據. 但是可使用自定義的維基傳輸安全協議如 或 ：

圖表擴展利用 設定解析這些協議. Note that because queries rely on the structure of wikibase items, they may suddenly stop working if the underlying data is edited and changes, as it may yield incomplete, empty or invalid data that can't be used to create a graph. In these cases the graph will end up empty (see T168601).

內部事務
When parsing, the Graph extension expands all template parameters/expressions, and stores the complete graph definitions in the ParserOutput, using graph hashes for IDs.

The graph extension adds HTML to the page where graphs should go, a with a graph-id as the attribute. 例子：

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.



安全功能
can be configured to disallow referencing untrusted data sources (e.g. Wikimedia only allows data from the Wikimedia sites).

许可协议
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.

wgGraphAllowedDomains
See the section on external data.

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. 有关更多详细信息，请参见T89287.

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.

Troubleshooting broken graphs
Errors with graphs will be logged in the developer console.

Error: Bad constructor arguments (T277906)
To fix: Replace filepath:Earthmap1000x500compac.jpg with filepath:Earthmap1000x500.jpg

例子.

TypeError: undefined is not an object (evaluating 'datum.firstYear.value')
To fix: Make sure you have not set default as null

例子.



參見

 * — for displaying graphs of sets of vertices connected by edges (i.e. not charts, like this extension)
 * Plotly — The open source JavaScript graphing library (with 3d charting capabilities)
 * D3 — Data-Driven Documents