std.algorithm for images

[Adam D. Ruppe]

bearophile wrote:
> I have tried the fractal tree program, the window doesn't close
> if you click on the button on the top right.

OK, I'll try it on Windows next time I have my laptop out. I've
been doing everything on Linux and Wine so far, so there's probably
a few little differences that need some attention.

There's still a lot of little things that need to be done to finish
it. Probably still several full day's work to cross the t's and dot
the i's.

> I suggest you to always compile your D code with -w, in
> imagedraft.d there is a switch (line 328) without default.

Changed. It's supposed to throw there (all values allowed
in the spec are handled), but I guess it would be better to
shut the compiler up and maybe use a more specific exception at
the same time.

> foreach(line; byRGBAScanline)

Annoyingly, this seems to be the prevailing Phobos style, so I'll
probably change to that. I personally dislike the string of
capitals, but best to be consistent with the rest of the lib.

> For few ideas look at Python PIL docs:

Hmm, it doesn't seem to have the interfaces required. While
we could make some monster classes that do all the work in
a black box, I'm hoping to take an STL approach here, where
the actual data structures are as de-coupled as possible from
the algorithms.

For that, an API listing doesn't help much.... we'll have to
study the requirements of the algorithms themselves. There is
a good list of things to look up there, though.