Ease development of server-side viewer panels

CHANGES.md

@@ -1,17 +1,30 @@
 ## Changes in version 1.4.0 (in development)
 
-### Enhancements
+### New Features
 
 * Added a new "share" action to the app bar.
-  It creates a permalink URL to restore the view state 
+  It creates a permalink URL to restore the view state
   and copies it to the clipboard. (#447)
-  
+
   The restored state includes
   - Selected map region, zoom level, and overlays.
   - User places including the selected place.
   - Opened panels, active tabs, and any selected options.
   - Other UI-specific states such as selected items, filters, or toggle states.
 
+* Starting with xcube Server 1.8 and xcube Viewer 1.4 it is possible to enhance
+  the viewer UI by _server-side contributions_ programmed in Python.
+  For this to work, service providers can now configure xcube Server to load
+  one or more Python modules that provide UI-contributions of type
+  `xcube.webapi.viewer.contrib.Panel`.
+  Users can create `Panel` objects and use the two decorators
+  `layout()` and `callback()` to implement the UI and the interaction
+  behaviour, respectively. The new functionality is provided by the
+  [Chartlets](https://bcdev.github.io/chartlets/) Python library.
+
+  A working example can be found in the
+  [xcube repository](https://github.com/xcube-dev/xcube/tree/5ebf4c76fdccebdd3b65f4e04218e112410f561b/examples/serve/panels-demo).
+
 ### Other changes
 
 * Updated dependencies, development dependencies and updated TypeScript code base accordingly.
@@ -20,7 +33,7 @@
     - `mui` from v5 to v6
     - `testing-library/react` from v12 to v16
 
-* Tooltips (incl. translation) have been added to the toogle buttons that 
+* Tooltips (incl. translation) have been added to the toggle buttons that 
   control the format of the metadata information in the sidebar.
 
 ## Changes in version 1.3.1

package.json

@@ -30,7 +30,7 @@
     "classnames": "^2.2.6",
     "codemirror": "^6.0.1",
     "color-rgba": "^2.2.3",
-    "chartlets": "^0.0.16",
+    "chartlets": "^0.0.29",
     "date-fns": "^2.29.3",
     "fast-memoize": "^2.5.2",
     "fflate": "^0.7.4",

public/docs/dev-reference.en.md

@@ -0,0 +1,31 @@
+## Server-side UI Contributions
+
+Starting with xcube Server 1.8 and xcube Viewer 1.4 it is possible to enhance 
+the viewer UI by _server-side contributions_ programmed in Python.
+For this to work, service providers can now configure xcube Server to load 
+one or more Python modules that provide UI-contributions of type 
+`xcube.webapi.viewer.contrib.Panel`.
+Users can create `Panel` objects and use the two decorators 
+`layout()` and `callback()` to implement the UI and the interaction 
+behaviour, respectively. The new functionality is provided by the
+[Chartlets](https://bcdev.github.io/chartlets/) Python library.
+
+A working example can be found in the 
+[xcube repository](https://github.com/xcube-dev/xcube/tree/5ebf4c76fdccebdd3b65f4e04218e112410f561b/examples/serve/panels-demo).
+
+## Contributions
+
+The following contributions are in use by this instance of xcube Viewer:
+
+${extensions}
+
+## Available State Properties
+
+In the following, xcube Viewer's state properties are listed.
+These properties can be accessed in the input and state channels you pass
+to the `layout()` and `callback()` decorators. To trigger a callback 
+call when a state property changes use the input syntax
+`Input("@app", <property>)`. To just read a property from the state use 
+`State("@app", <property>)`.
+
+${derivedState}