Documentation/pg-plugin-styling.txt

= Gerrit Code Review - PolyGerrit Plugin Styling

== Plugin styles

Plugins may provide
link:https://www.polymer-project.org/2.0/docs/devguide/style-shadow-dom#style-modules[Polymer
style modules] for UI CSS-based customization.

PolyGerrit UI implements number of styling endpoints, which apply CSS mixins
link:https://tabatkins.github.io/specs/css-apply-rule/[using @apply] to its
direct contents.

NOTE: Only items (i.e. CSS properties and mixin targets) documented here are
guaranteed to work in the long term, since they are covered by integration
tests. + When there is a need to add new property or endpoint, please
link:https://bugs.chromium.org/p/gerrit/issues/entry?template=PolyGerrit%20Issue[file
a bug] stating your use case to track and maintain for future releases.

Plugins should be html-based and imported following PolyGerrit's
link:pg-plugin-dev.html#loading[dev guide].

Plugins should provide Style Module, for example:

``` html
  <dom-module id="some-style">
    <style>
      :root {
        --css-mixin-name: {
          property: value;
        }
      }
    </style>
  </dom-module>
```

Plugins should register style module with a styling endpoint using
`Plugin.prototype.registerStyleModule(endpointName, styleModuleName)`, for
example:

``` js
  Gerrit.install(function(plugin) {
    plugin.registerStyleModule('some-endpoint', 'some-style');
  });
```

== Available styling endpoints
=== change-metadata
Following custom CSS mixins are recognized:

* `--change-metadata-assignee`
+
is applied to `gr-change-metadata section.assignee`
* `--change-metadata-label-status`
+
is applied to `gr-change-metadata section.labelStatus`
* `--change-metadata-strategy`
+
is applied to `gr-change-metadata section.strategy`
* `--change-metadata-topic`
+
is applied to `gr-change-metadata section.topic`

Following CSS properties have
link:https://gerrit.googlesource.com/gerrit/+/master/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata-it_test.html[long-term
support via integration test]:

* `display`
+
can be set to `none` to hide a section.