Re: Can your GUI framework do this?

Martin,
I'm one of the contributors to Monkeybars, which is our JRuby GUI  
framework that sits on top of Swing.
Here's how Monkeybars handles this:
1. A component consisting of a series of existing components hooked
together to act as a single widget
In Swing, it is typical to inherit from the component that gets you  
closest to what you want, and add stuff to there. What you are  
thinking of is probably a JPanel. While you could inherit from a  
JPanel, put in the functionality or other components that you wanted,  
and drop it in where you wanted to use it, we feel there's a better  
way. Monkeybars uses MVC's delegation of responsibilities to help us  
out with testing and  keep the code more sensible. As such, we felt  
the best way to approach this would be by providing mechanisms that  
allow one MVC tuple (your top level window) to nest other MVC tuples  
(reusable components). This means that controllers communicate with  
other controllers. Views interact with simple view components  
directly, but not complicated "partials".
Here's your example: An icon widget, that combines  a picture and a  
textfield
underneath, with config options to turn either off or size the image,
make the text editable, etc"

In Monkeybars, the picture/text field grouping would be handled by its  
own model, view, and controller. This is how you'd tie that in:
class MainView < ApplicationView
   # nesting defines how the component will be added or removed when  
add_nested_controller or
   # remove_nested_controller is called. This nesting is one of the  
simpler ones that just drops in the
   # component as is. There are more complicated variations that allow  
you to write all code you want to
   # determine layout specific arguments, positioning, and layout  
validation.
   nest :sub_view => :image_name, :view => :image_name_panel
end

class MainController < ApplicationController
   def load
     @text_image_controller = TextImageController.create_instance
     # this will kick off the nesting for any nesting with a sub_view  
of :image_name
     add_nested_controller :image_name, @text_image_controller
   end
end

2. A component built 'from scratch' atop a canvas, that is, handling
its own drawing and event management
Since we're using Swing, one could override the paintComponent method  
on the Swing component used in the view. We've done some of this to  
render real-time animated graphs with peak bars and graph transitions.  
We even have it so each graph bar has it's own tooltip text.
Here's your example: A speedometer-type dial with a configurable range  
and tick interval
In this case, I'd write my own view component by hand (typically we  
use a designer for it).
A speedometer could be made by using some of the Java2D stuff out  
there during paintComponent. The needle could be drawn with simple  
line methods where you specify start and end coordinates. The ticks  
could be drawn similarly as partial lines. I'd imagine some trig would  
be involved in the calculations. I would also check to see if any Java  
folks had already done this, as Java/Swing have been around for a long  
time.

3. A component combining a canvas and existing widgets
I'd want to make the painted canvas widget into a nested controller,  
so my canvas wouldn't have to care about stomping on other components  
when it redraws itself.
For your example: A box that holds a component and paints a customised  
border around it
This is actually pretty simple in Monkeybars. You can just set the  
boarder of many (if not all) Swing components. We have a live example  
using this that you can run via Java Web Start here:
http://www.happycamperstudios.com/monkeybars/twit/Twit-and-Twitter.jnlp
Here's the snippet that makes the drop-shadow border happen:
@image = Java::javax.swing.JLabel.new
@image.border = Java::org.jdesktop.swingx.border.DropShadowBorder.new
The drop shadow comes from the SwingX library.
I'd also like to note that example won us the GUI part of the script  
bowl competition at Java One (us being JRuby).
4. A container that takes a collection of widgets and lays them out
according to some userdefined algorithm
There's a ton of ways to do this using Swing using Layouts.
Your example: A pure-ruby implementation of a wrapbox
(http://zem.novylen.net/ruby/wrapboxdemo.png)
This works out of the box just by using a FlowLayout in your  
container. That can be as simple as this:
@main_view_component.layout = Java::javax::swing::FlowLayout.new

Some other stuff:
Monkeybars has a lot of options for configuring view mappings. View  
mappings define how data moves from your model to the components in  
your view, as well as how your components' data moves into your model.

One thing that was really important to us in Monkeybars was that for  
moderate to large projects, a large update method in a controller that  
intimately knew about the components used made testing incredibly  
painful. We designed Monkeybars such that most communication between  
the view and controller is done through the model via the mappings  
mentioned above. Controllers may also send signals to the view for  
lightweight or secondary renderings. There is no direct communication,  
however. This makes testing super easy.

You _could_ write Java if you wanted, but we haven't run into  
occurrences where Java (the language) is needed. You could write all  
of your designs by hand in Ruby, which is fine. My preferred approach  
is to use a designer tool, such as Netbeans.
Do you really want to lay something like this out by hand?
http://www.happycamperstudios.com/monkeybars/charlotte%20interface.png


Swing is a part of Monkeybars. We provide some simplified ways to  
communicate with it (such as implicit event handlers). However,  
Monkeybars doesn't shield you from Swing. This is both a pro and a  
con. Swing is a powerful library, but it also has a lot of quirks.  
Thanks to the folks at JRuby, we have Rubyized methods to all of our  
Java proxies, and some nice implicit type conversions that make  
integrating with Java look fairly natural. Monkeybars just makes Swing  
more palatable, and provides a nice quarantine zone to place all of  
your Swing code (in the view).

You're in JRuby, and that means you're in Java. Java buys you a built- 
in JIT engine. JRuby's team has told everyone to flag occurrences  
where MRI is faster as bugs. You also can run your code on any machine  
with Java installed, and it's hard to find machines without Java.  
Monkeybars itself is just a jar that happens to be a library. No Ruby  
installation is needed! Leveraging Rawr you can also wrap your jars  
in .exes or .app files. You can even use Java Web Start to hand  
someone a link and the app will auto-install/update and run. You could  
also integrate Monkeybars into your existing Java app, and start  
writing all of your new code in Ruby. Java also has a lot of mature  
code out there, as it has been around for a long time. One personal  
experience I had was using SNMP. Ruby's SNMP library is great for  
getting you started, but falls apart when you need to use the more  
secure SNMPv3. SNMP4J has been around for a while, and is still active.

I know a lot of the Ruby community has some bitterness towards Java,  
but this isn't Java the language we're using here, it's Java the  
platform. I encourage anyone interested in GUI development to take a  
peak at our examples and screencasts:
http://monkeybars.rubyforge.org/
http://monkeybars.rubyforge.org/tutorials.html

-Logan