[csjava-developer] notes on harriet release

[Toby D. <tjd...@gm...>]

I've been looking at the original feature list for the harriet  
release, and it needs to be changed and firmed up given what has  
actually been implemented in the casey version.

I think the main change in harriet should be a fundamental re- 
structuring of TheMatrix. Right now, TheMatrix combines the behaviour  
of a BufferedImage and a JFrame into one class. This is simple and  
convenient for beginners, but it makes it awkward to do more advanced  
things, such as adding your own buttons to the frame, or put the  
image in some other frame in a window.

The  current way around this is to use TheMatrix.getImage() to get a  
reference to the BufferedImage, and then use the plain BufferedImage  
as needed. This works, but the problem is that the extracted  
BufferedImage  lacks all the nice extra features that TheMatrix  
implements for it (e.g. making copies, multiple set/get methods,  
saving/loading, etc.).

So the "obvious" solution (which in fact has taken me some time to  
realize as obvious) is to create a new class that extends  
BufferedImage, and implements all the nifty extra methods we want for  
BufferedImage. Then, we create special JFrame-derived methods for  
displaying these images.

While we should be able to keep the original calling behaviour of  
TheMatrix, this new design will allow calling code like this:

    FancyBufferedImage im = new FancyBufferedImage("pic.jpeg");

    // ... process the pixels of im without displaying it ...

    show.asPlainFrame(im);

We can make as many "show" methods as we like (maybe with better names).

Any comments?

Toby
--
Dr. Toby Donaldson
School of Computing Science
Simon Fraser University (Surrey)