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Re: [E-devel] edje canvas objects



Quoting "jose_ogp@juno.com" <jose_ogp@juno.com>:

>
> >    Jason writes:
>
> > > >	Much ado about gradients, but hopefully all this will make
> > > > it easier to work with grads in current edje and otherwise.
> > >
> > > Forgive me for chiming in when I haven't read the full thread
> > > nor grokked the context, but does any of your work allow being
> > > able to set gradients as clipping objects?  The ability to clip
> > > a text object with a gradient to allow fading text out is
> > > something I've wanted to be able to do for a long time.  :)
> > >
> > > Cheers,
> > > Jason.
> > >
> >	The short anwser is no. Only rectangle objs work as clip
> > objs in evas at this time.
> > 	The longer anwser is that yes, there is a way you can
> > do this right now - if you use a buffer evas for your text output.
> >
> >	You would setup your buffer evas (make sure it's set to
> > have-alpha). Then add your text obj and add a suitable grad obj on
> > top of that -- AND set the grad obj's render-op to EVAS_RENDER_MUL.
>
> 	Just thought I'd follow up on this a bit... Note that in the
> above one can also use an image object, indeed all renderable objects
> respect the various render-ops (only for buffer-engine based evases
> right now, though the 'mul' render-op only behaves like 'clipping'
> for non-shape like objs, eg. images/grads).
>
> 	Likely evas will have general obj clipping not too far away,
> but 'buffer evases' are also interesting and useful (hence the
> ecore sub-canvases).

I think it would be indeed really useful to have such objects:
I may be wrong but I think this kind of objects is the way to go if we want to
support blitting in Evas. It should improve the perfs a lot when we have to
scroll large areas of screen (the scrolling part would just be a subcanvas, so,
in order to scroll, we would just have to move this subcanvas. No need to redraw
all the objects of the subcanvas).
We could maybe implement this in the smart objects: A smart object could render
(if we say so) in a subcanvas, so moving the smart object won't require to
redraw all the sub objects.

Regards,
Simon TRENY <MoOm>