[OpenLayers-Dev] quick summary

[Bart van den Eijnden (OSGIS)]

This is for sure something that a lot of people have been waiting for.

Thanks everyone, including the people doing this hacking marathon!

I look forward to start using this new vector stuff.

Best regards,
Bart

Christopher Schmidt schreef:
> Quickshot summary of the past couple days of OpenLayers hacking:
>
>  * Created new branch from trunk, /sandbox/vector-2.4
>  * Moved in:
>    * Layer/Vector.js
>    * Renderer/*
>  * Changed:  
>    * Feature.js -> Feature.Vector. There are now two features -- one
>      designed for use with Markers, popups, etc. and one designed for
>      use with geometries.
>    * Parser/Writer classes now in a single 'Format', which has read()
>      and write() functions which switch between strings and collections
>      of features. This means that ot create a layer which is like the
>      GML layer (accept a URL, put features on the map) but which 
>      parses, for example, GeoRSS, requires only writing a Format() class
>      for it, and then changing a single line of code.
>
>      This also means that it is possible to take any vector layer and
>      serialize it to GML with a single function call. (var g = new
>      OpenLayers.Format.GML(); gml = g.write(layer.features);)
>      
>    * Layer.GML and Layer.WFS now use this Format class:
>      http://dev.openlayers.org/sandbox/vector-2.4/examples/gml-layer.html
>      http://dev.openlayers.org/sandbox/vector-2.4/examples/wfs-t.html
>      (saving WFS-T doesn't work yet. I'm still working on it :)
>    
>  * Major changes:
>    * Attributes() parsing moved into the Format() class. This makes it
>      easier for other formats, but may be a performance hit. (However, I
>      have run one hundred features through the GML parser and not had
>      any speed problems: the speed problems are typically in rendering
>      rather than raw XML parsing). This means that feature.attributes is
>      now just a dict, rather than an object with an XMLNode attached.
>      This means that all attribute parsing is done in one location,
>      which makes it much simpler across the code.
>    
>    * Style.js is going away. Instead, there is an
>      OpenLayers.Feature.Vector.defaultStyle (similar to
>      OpenLayers.Marker.defaultMarker) which encapsulates the default
>      style: various other styles will be stored where appropriate,
>      usually in the controls.  
>    
>    * MouseListeners seemed to boil down into a concept of 'handlers': 
>      there are several types of events on the map which should be encapsulated
>      in handlers which have various actions. ("draw box", "draw point",
>      etc.) So, there are now 'handlers' which handle the action of
>      drawing a point. Controls can then turn these handlers on and off:
>      this will allow trivial building of controls like the toolbar,
>      because each handler has an idea of whether it is activated or
>      deactivated, a toolbar only needs to encapsulate mechanisms for
>      turning these functions on and off.
>
>      http://dev.openlayers.org/sandbox/vector-2.4/examples/draw-point.html 
>
>      Checking the box turns the point drawing control on. 
>      Uncheckint it turns it off. 
>
>      This also changes the 'box' mechanism such that you can easily tkae
>      a box and do whatevery ou want with it. Handlers return the feature
>      that was drawn with them, essentially: so when you draw a point
>      with the DrawPoint handler, it returns the point. When you draw a
>      box with the zoombox handler, it reutrns the box.
>
>      If you look at the source of:
>
>      http://dev.openlayers.org/sandbox/vector-2.4/examples/custom-control.html
>
>      You can see the draw() of the control creates a 'Box' Handler
>      (Handler.Box), and assigns the 'done' callback to call notice().
>      This means that when the Box handler is done with drawing the box,
>      it will call the notice function -- with the bounds of the box. The
>      control can then do what it wants with this. In some cases, (mouse
>      defaults) this might be to zoom to the bounds described by that
>      box. In this case, it just 'alert()'s the pixel coordinates of the
>      box.
>
>      This solves a whole host of 'how do I change the behavior of'
>      questions: it encapsulates the Handling of mouse events at a lower
>      level than registering on the map, and the result is that somewhat
>      hacky code (like that in MouseDefaults) moves down a level, making
>      what MouseDefaults will soon be a very simple control which just
>      sets up a set of handlers.
>
>
>  * Testing:
>    * Currently, the geometry classes have more than 150 tests. Erik has
>      done an excellent review of these classes, and has pronounced them
>      complete... I think :)
>    * Renderer, Format and Layer tests are coming up the pipeline.
>  
>  * Documentation
>    * The planned route for API documentation is JSDoc, and the JSDoc
>      comments have been kept together for most of the code (though a few
>      classes that I wrote need better docs ;))
>    * There are examples demonstrating how to add simple features to
>      layers, and that API is unlikely to change. Very little API change
>      has happened at all betweeen the vector and vector-2.4 branch, so
>      if you were using one, you should be fine with the final version
>      that goes to trunk.
>
>  * Future plans:
>    The desire is to get this stuff as done as possible this week such
>    that we can walk away from the Cambridge OpenLayers Hackathon with
>    a working branch, and hten soon after, merge it to trunk. We are
>    hoping to get everyone on board for a 2.4 release in the next 2
>    weeks with vector stuff -- even if some features and functionality
>    are not complete -- so long as there is a consensus that the
>    existing API is solid and unlikely to change. This will let
>    everyone work on continuing development of the vector code *on trunk*
>    rather than on a branch.
>
> I just want to offer a *huge* thank you to all the people who have made
> this possible. The work on the vector branch is the only thing that has
> made this development possible, and a *lot* of people took part in
> making that happen. Camptocamp's participation especially took this code
> from being a great idea to being a great tool. The vector branch is a
> core example of the widespread diversity of the Open Source community
> participation that has led OpenLayers to become such a great project,
> and I am extremely grateful -- both as a project contributor and
> *personally* -- for all the work that has been done and all the great
> feedback we've gotten.
>
> Thank you, thank you, and thank you again. It is because of development
> like this that OpenLayers is going to continue to move onward and upward
> into becoming the best mapping API out there.    
>      
> Regards,
>   


-- 
Bart van den Eijnden
OSGIS, Open Source GIS
bartvde at osgis.nl
http://www.osgis.nl