Re: Graphics properties as objects

[Michael Goffioul]

On 1/3/08, Shai Ayal <address@hidden> wrote:
> Michael, I can share the work. I am not confident enough I understand
> you skeleton, but if you post a giude like I did once: "HOWTO add a
> new property", I will try and make an awk script to automatically
> generate as much of it as possible.

Hi,

While trying to implement my ideas in current graphics code, it appeared
that using an interface class "property" (mainly there for reference counting)
was not very handy: props are stored as "property" fields and you somehow
loose the typing of the property (you can get it back with methods like
as_xxx_property(void), but if you return a const-reference, you can't do
whatever you want with the property).

Another possibility is to deal with pointers:
1) get rid of the "property" class and store props as pointers to typed
property classes:

    string_property *string;

2) implement accessors like:

    string_property* get_string (void) const { return string; }
    void set_string (const octave_value& v)
      { string->set (v); }

3) register all properties in a map in base_properties class:

    std::map<caseless_str, base_property*> all_props;

4) property objects are created in the nested "properties"
classes ctor

5) property objects are deleted in ~base_property() by
iterating over all_props

I know this scheme does not fit well in the rest of octave code,
so would this still be acceptable? Any other better idea?

Michael.