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List:       kde-core-devel
Subject:    Re: Transparency -- take 2
From:       Antonio Larrosa <antlarr () arrakis ! es>
Date:       1999-10-04 5:56:18
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Geert Jansen wrote:
> 
> Antonio Larrosa wrote:
> 
> > Currently you just have to use the class RootPixmap (defined in
> > rootBg.h)
> > and set a call to RootPixmap::setBackgroundPixmap(yourwidget); not much
> > more.
> > You just have to change the function loadWallpaper to load it from
> > the root propierties instead of from disk.
> 
> Well, if you strip all the rendering code from RootPixmap, you end up with
> about 20 lines (in my version) of C++ for copying the shared pixmap :) So

Not just 20, but there are only a few more, you're right :-)

> the duplication effort is not that big :) And I did a general pixmap sharing
> class which is IMO preferable over your desktop-background-only version.
> It has a similar API. Something like:
> 
> QPixmap background = KSharedPixmap::copy("kde_desktop_1", aRect);
> 

Looks good, but that's not a similar API, the api of RootPixmap is
something like:

rootxpm=new RootPixmap;
rootxpm->prepareBackground(redting,greentint,bluetint); // if desired
rootxpm->setBackgroundPixmap(mywidget);

the solution would be just to substitute the calls to generateBackground
in RootPixmap with a call to KSharedPixmap. As I see it, your
class is much more abstract and generic, but RootPixmap has an easy api
for use of transparent widgets. Anyway, I tought I read something very
similar to it in your original proposal.

With RootPixmap, you just have to take care to call setBackgroundPixmap 
again when you resize the widget, move it, or change desktop (and also,I
suppose kdesktop should emit a signal telling when it has changed the
desktop background, and send signals each few seconds when using
something like xearth). In the future RootPixmap will (if I or someone
else find the time :-) ) automatically set an event handler for those
events and set the transparent backgrounds as necessary without the
developer having to call it specifically.

> will get you a copy of the desired piece of the desktop background.
> If you want to take a look at the code, I'll mail it to you, it's already
> done.
> 

If it works so well, you should put it on the libs I think, I'll have
a look then. If you don't think so, just send it to me (if it isn't too
big)

> > The major changes should be done to kdesktop, which is a thing I won't
> > talk about as there are others who know much more than me about it.
> 
> Yes, I was primarily talking about kdesktop. If the changes are done there,
> the client implementation is easy.
> 

Exactly,

> > Reuse what's already written :-)
> 
> Hey, that's my slogan! (really) :)
> 

:-)

Greetings,

--
Antonio Larrosa Jimenez
Student of Mathematics
antlarr@arrakis.es        larrosa@kde.org
http://www.arrakis.es/~rlarrosa
Klein bottles for rent -- inquire within.

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