[cl-cairo2-devel] XLib-context and UIs

[Tamas K Papp]

On Sun, Aug 12, 2007 at 10:22:38AM -0400, Joubert Nel wrote:

Hi Joubert,

> I'm keen on using CL-Cairo2 as a means to draw GUIs. I've done some
> initial exploration of the library and am wondering:
> 
> 1) There's an xlib-context example, but the windows are fixed-size. Is
> it possible to make resizable windows?

The main problem with X is refreshing the window when X asks for it
(ie the window receives an Expose event).  In order to do it
correctly, you either have to keep track of all operations or
double-buffer.  cl-cairo2 does the latter, as it is easier to
implement, but this does not allow resizing.

Peter Hildebrandt experimented with the former approach:

http://groups.google.com/group/comp.lang.lisp/msg/9258d245145323b3

you might want to ask him about the current status.  This approach
would allow resizing, but is more complicated.  If you know what
subset of cl-cairo2 you will be using, perhaps you can get away
implementing recording operations for that subset.

> 2) Is it possible to receive mouse and keyboard events int the
> xlib-context?

The framework is there, you just have to write and event handler.  

A new version of cl-cairo2 will be released tomorrow, which contains a
rewritten x11 surface, implemented entirely in Lisp using CFFI (no
extra C glue).  If you want to refine the event handler, I suggest you
wait for that and your job will be much easier.

Best,

Tamas