From graphics-request at octave dot org Thu Feb 16 03:06:36 2006
Subject: Re: Minimal requirements from a handle graphics package
From: Ole Jacob Hagen <waterthrill at yahoo dot no>
To: Shai Ayal <shaiay at gmail dot com>
CC: graphics at octave dot org,         octave maintainers mailing list <maintainers@octave.org>
Date: Thu, 16 Feb 2006 10:04:51 +0000

Hi,

Following objects should also be included into the handle graphics package:

image
uicontrol
uimenu
uicontextmenu
light
rectangle

Command: delete must be included.


And which M*lab version should our handle graphics package be compatible
with?
R11, R12, R13, R14? Mathworks has redesigned their handle graphics
package, from R13 to R14.

Should we strive for R11 or R13 compatibility ?

You can also find similar low-level functions  in oplot as well. You can
browse online here:
http://cvs.sourceforge.net/viewcvs.py/oplot/oplot/src/octave/

You'll find that both octplot and oplot has the same low-level
functions. They both are dispatching, creating aliases for their functions.

The low level function set/get are used in a similar way in both octplot
and oplot

Oplot version of set/get calls oplotcom(....), while octplot versions
calls the octplot_command(....)
See examples at the end of this mail. So octplot and oplot is more
alike, than you would like to prefer, I guess. Octplot uses also a
similar toogle mechanism as enabling/disabling usage of graceplot. 
These m-files can be retrieved from octave-forge. It handles the order
of the search directories in the loadpath used in Octave.

Oplot uses props for handle graphics storage, while octplot is a
Props-less implementation...This it not entirely true, or is it Shai?
You are calling MAKE_REF(...) to make properties available to both read
and write.

I can see that you've created your own Props-similar implementation? I
am refering to the prop-prefixed cpp-source files in octplot. 

Oplot has a handle graphics storage, that are used by the rendering
classes, and they are not "glued" together.

Therefore I would say and claim that octplot and oplot is very alike.
Same principles, but different software design in some areas.

Besides, we have exchanged files from each other.

The handle graphics functionality restricts developers in designing and
implementing visualisation application to octave supporting handle
graphics.

The same minimum amount of low-level functions have to be shipped: line,
surface, image, patch, text, figure, axes, set, get and delete.  These
must be shipped to ensure minimal visualisation functionality.

This require that the following graphic objects are supported: root,
figure, axes, line, surface, patch, image and text.

If octave shall provide a library for the graphical objects at all, the
Props library or a similar library would be preferable. Props can be
used internally by Octave, or by the visualisation application. It
should be noticable that Props used internally inside Octave doesn't do
any visualisations. For a graphic less props browse
http://cvs.sourceforge.net/viewcvs.py/oplot/oplot/props/octave/

This could be nice to use, if you want to handle/experiment with handle
graphics without visualisation, and to experiment on how props really
works.

Props was designed and developed during a bachelor thesis written by my
brother, Hans O.

Cheers,

Ole J.



Comparison set.m
oplot:

> function *oset*(varargin)
> oplotcom(*"set"*, varargin{:});
> end

octplot:

> function *oset* (varargin)
>   *if* (length(varargin)<3 || mod(length(varargin),2)~=1) ,
>     usage('set(hnd,prop,val[,prop,val])');
>   endif
>   
>   hnd = varargin{1};
>   *for* ii=2:2:length(varargin),
>    *for* jj=1:length(hnd),
>       octplot_command('set',hnd(jj), varargin{ii},varargin{ii+1});
>    endfor
>   endfor
>
> endfunction
>

get.m

oplot:

function x = oget(varargin)
x = oplotcom(*"get"*, varargin{:});
end

octplot:

> function _out = get (varargin)
>   
>   *if*(nargin<1)
>     usage(*"get(hnd,[prop])"*);
>   endif
>   
>   hnd = varargin{1};
>   *out* = cell();
>   oi =1;
>   *for* ii=1:length(hnd)
>     tt = octplot_command(*"get"*,hnd(ii),varargin{2:length(varargin)});
>     *out*(oi:oi+length(tt)-1) = tt;
>     oi += length(tt);
>   endfor
>   
>   *if*(length(*out*) ~= length(hnd))
>     ## means we were returned a list of all properties
>     printf(*"\nProperty list\n\n"*);
>     *for* ii=1:length(*out*),
>       printf(*"  %s\n"*,*out*{ii});
>     endfor
>     printf(*"\n"*);
>   elseif( length(*out*) == 1)
>     _out = *out*{1};
>   elseif( length(*out*) == 0)
>     _out = [];
>   *else*
>     _out = *out*;
>   endif
>
> endfunction