Comments on Artlib backend

[Fred Kiefer]

Hi Alexander,

I looked at your great backend based on the libart library. I am quite 
impressed by all the composite operator code, as all the other backends 
have been missing this and the way you implemented it looks like it 
could be reused for most of them. But before we can do this, a few 
questions must be cleared:

Currently some of the files are still copyrighted to you, as far as I 
understand it this will be a problem for GNUstep. (Adam, please correct 
me if I am wrong here)

The current file structure is a bit confusing to me. The ArtContext and 
the ARTGState share one file, but should be separated into two. And 
blit.m includes itself multiple times, whereas this could easily be 
replaced by a new file that would include blit.m.

There is an implementation of DPSarct in ARTContext.m, could this be 
used as the starting point to implement this method in GSGState? And how 
about the method appendBezierPathWithArcFromPoint:toPoint:radius:?

There is some code duplication. The methods for NSBitmapImageRep could 
be moved to x11, the best solution would be to move the whole file 
XGBitmapImageRep.m to this directory, renaming it in this process. Than 
this code could be used by all the X based backends.

The beep method on ARTContext looks like a left-over from a previous 
version.

Currently ARTGState keeps its path in user space (Which is already 
stated in the code as being a problem). As far as I understand this, it 
is done to allow for the dash to be adjusted, but this is currently not 
used. So I dont see any reason for this and we could use the GSGState 
path methods instead of specific methods here.

I like the idea to have a method to get the current path. This propably 
is the only way to implement the NSBezierPath glyph methods. Could we 
move this to GSGState?

What I did not understand at all is what the RDS environment is and how 
this backend should be compiled for it.

I hope that at least a few of this questions, statements make sense and 
help us to simpler and more powerful backends.

Cheers Fred