Re: handle graphics

[Brian Blais]

John W. Eaton wrote:
> Is anyone actively working on implementing handle graphics for Octave?
>
> I've been thinking about this recently.  My first thought was to
> create a structure array to describe the figure windows.  

Although I haven't worked on it for graphics, I did make a quick 
handle-based GUI implementation, using FLTK as a backend.  You can see 
it at http://web.bryant.edu/~bblais/octave/

I used a structure array, and the handle passed is the index into that 
structure array.  All of the handle manipulation is in the m-files.

>  It seems that Matlab graphics handles are some kind
> of pointer value encoded in a double object.  Using only the scripting
> language, how can we use something like that to lookup the location in
> a complex structure array? 

I think that the matlab handle is something like:

        figure_number+object_number/100000

so you can get both the figure number and object number from some simple 
math.  if you count all objects (including figures) as equal, then you 
don't need a double value.

                        
                        Brian Blais



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