A couple of months ago, I was daunted by the prospect of having to do yet another Look and Feel set of subclasses for the VisualWorks widget set. The technique of subclassing is hopelessly over-leveraged in what is there.

The debate about whether to do native widgets or not, and in what form factor has gone round and round for years now. It will continue to do so. Somewhere in there, I pondered "what would happen if I could draw standard widgets faithfully (or pretty darn close), but still emulate them? Is there a half way point there?"

I found that for OSX and Windows, there actually was to some degree. I discovered that all of the graphic resources that OSX uses are actually in a database and can be pried out and reused. You have to make the right decisions about how to use them, but if you use them correctly, you're doing the same thing OSX is. On Windows the story was even better. uxTheme.dll is the theming engine that Windows uses to evolve it's look and feel, as well as customize widgets for other platforms (such as mobile devices) -- much thanks to Michael Lucas-Smith for pointing me towards this.

So I began experimenting with that, and some other ideas that we've already been hinting at, in a package that I dubbed Skinny. It's so dubbed, because I'm interesting in getting to a point, where changing the skin of a VW app (whether the IDE itself, or something else), is relatively easy.

Here's a screencast that shows me playing with version 93 which is in the Open Repository.

Here's a list of questions/answers one might ask about such an experiment:

Q: Which versions of VisualWorks do I have to have for this?

A: You need a pretty recent 7.8 dev build. There are small things from this project, that we've been rolling into VisualWorks proper.

Q: Do you plan on integrating this in the product someday?

A: I don't know yet. It could be that we end up doing yet another subclass tree and just harvest the uxTheme.dll drawing know how. Or maybe more of a hybrid. I don't know yet.

Q: Does the Windows look and feel work on other platforms?

A: No. It doesn't.

Q: What other skins have you played with?

A: There's an OSX one. It uses Cairo to render the various graphics excavated out the OSX graphics database. Ironically, it actually works better at the moment on either Windows of X11, since Cairo doesn't interleave efficiently with Quartz drawing. It works there, but it's pretty jerky. Great benchmark for really improving Cairo on OSX.

Q: Which widgets have you built for?

A: Push Buttons, Radio Buttons, Check Boxes, Scroll Bars, Tab Controls, Splitters (the splitters don't build thru UIBuilders tho)

Q: What if I'm more interested in not using UIBuilder technology and just simply snapping widgets together?

A: Look at the various class side example methods on Skinny objects.

Q: What known issues are there already?

A: Haven't made any of them keyboard navigable (waiting to integrate some changes to the core to simplify KeyboardProcessor first). The Scrollbars don't get their thumbs sized initially right, they require a click to do so. Lots of others, I'm sure.

Q: What IDE tools seem to work?

A: In the screencast, I show workspace, inspector, and settings tool. There's actually one page in settings tool that has issues still (a store one with a dataset). The browser kind of works. Some of the widgets don't pick up the skinny skin. The FileBrowser tanked last time I tried it. I have used the debugger on it successfully before, but currently have it turned off.

Q: Why are you blogging about it?

A: Always a good idea to give people a peek at what kind of things are going on. I'd also be interested in people trying to use it with their own apps. I'm curious how long it would stay alive and if there's an obvious "implement this next" vector.