This would only work in very limited circumstances. I think you're confusing
the theme property itself and its contents. To make an analogy with
dereferencing a pointer, you have these levels:
(Theme object/property IDs)
---pgThemeLookup--->
(Property contents, may be a handle)
---Handle dereference--->
(Actual bitmap, string, font, etc. data)
The problem is, the pgThemeLookup mapping is not a one-to-one relationship.
When you load a new theme, it may change multiple theme properties to the
same new value, or it may change the inheritance so that a theme property
returns a different pre-existing handle.
The suggestion I made would assimilate these two dereferences into one
dereference, so that every time the handle is used, it would re-check the
theme also.
However, both of these ideas fail to account for theme properties that don't
use handles (which are usually in the majority- things like colors and
sizes) and those would have to be assigned using another method, like a
theme reload event.
On Tue, Jun 11, 2002 at 08:55:08AM -0600, Eric Christianson wrote:
> I have what is likely a naive question. If there could be such
> a solution where a pointer to a theme property could be established,
> why couldn't loading a new theme just generate the same id as
> the one being reloaded? In other words, if I have a theme object
> foo, it gets generated a handle, right? If I load a new theme, if
> the new theme has an object foo, why can't it get assigned the same
> handle? If this were possible, it wouldn't have any performance
> penalties, and still make the client-side easier to program.
>
> There is a potential resource leak, but if the same code that loaded
> the new object also freed the one it was replacing, this would work.
> How is the general case handled when two theme files are loaded and
> they both specify the same property? In other words, panel is described
> in two theme files, and they are both loaded at the same time?
>
> I notice that if I set a theme property to one of the default objects,
> say "panelbar", when the theme is reloaded it is re-displayed correctly.
> It's only with custom objects, that a propblem seems to arise. But with
> custom theme objects they are associated by name. Coudln't pgserver
> reload these properly based on the name of a new theme object replacing
> it?
>
> On Mon, 2002-06-10 at 23:46, Micah Dowty wrote:
> >
> > This is a problem that Eric Christianson and I were discussing, and I came
> > up with a few solutions, but I thought the rest of this list might want to
> > have a say in it (And this sounds like the kind of problem Yann might like ;)
> >
> > When a theme is loaded or unloaded, pgserver has code to handle redoing
> > theme lookups where necessary. Apps however don't have a chance to do this.
> > Therefore, any handles the app has that were owned by the removed theme
> > become invalid.
> >
> > The most obvious solution to this is to have pgserver send an event to all
> > apps when a theme is loaded or unloaded. This would be necessary for
> > non-handle properties looked up from themes.
> >
> > Another option that may be implemented concurrently with the event solution
> > is to create a new type of handle that specifies a theme object and
> > property. This handle, when dereferenced, would automatically do a theme
> > lookup and additional dereference. It would effectively be a pointer to a
> > theme property with a pointer to a pointer :)
> >
> > Anyway, this new type of handle would be less efficient per-use but more
> > efficient per theme reload. It would never become out of date with respect
> > to the loaded themes.
> >
> > --
> > Only you can prevent creeping featurism!
> >
> > _______________________________________________________________
> >
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> >
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>
>
> _______________________________________________________________
>
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