[Interest] some doubts about current graphics stack in Qt 5.1

[pritam.ghanghas at gmail.com]

On Tue, Dec 10, 2013 at 8:20 PM, pritam.ghanghas at gmail.com <
pritam.ghanghas at gmail.com> wrote:

>
>
>
> On Mon, Dec 9, 2013 at 9:16 PM, Thiago Macieira <thiago.macieira at intel.com
> > wrote:
>
>> On segunda-feira, 9 de dezembro de 2013 15:43:22,
>> pritam.ghanghas at gmail.com
>> wrote:
>> > Within Qt
>> > QtWIdgets use QPainter, which can use raster, native or opengl backends.
>>
>> There's no native backend anymore.
>>
>> > Most of the time it will be raster. But if one is using QGLWidget or
>> sets a
>> > QGLWidget as viewport. QPainter will switch to opengl. There are non
>> > programmatic ways as well to make OpenGl default.
>> >
>> > QQuick always uses opengl API (it may not be hardware accelerated if
>> mesa
>> > or angle is used)
>>
>> ANGLE is accelerated. It's meant to translate OpenGL ES 2 to DirectX,
>> which is
>> usually accelerated.
>>
> That one slipped as I was too concentrated on OpenGL. Thanks for
> correcting.
>
>>
>> > Now a little specific, how does webkit rendering is done. Using
>> QPainter,
>> > opengl or it follows the same rules as above.
>>
>> QPainter.
>>
>> > ################# 1 #############
>> > QWebView view;
>> > view.show();
>> >
>> >
>> > ################# 2 ##############
>> > QGraphicsScene scene;
>> > scene.addWidget(new QWebView);
>> > view.addWidget(&scene);
>> > view.setViewport(new QGLWidget);
>> > view.show();
>> >
>> > I would assume 1 is using raster and second one is using opengl.
>> > Are there any platforms where 2nd will be slower than first?
>> > And what about WebView QML element?
>>
>> Everything is raster with WebKit. Web content was not designed for OpenGL,
>> except for WebGL.
>>
> So you are saying that the above two cases are same.
>
Ok, I got my answer after a a little thought. When we set the viewport
scene will render its items using gl backend but webview item will be
rendered with QPainter because that is the only way. Scene will then use
that pixmap while rendering rest of the scene.
Thanks for pointing me in the right direction.

>
>> --
>> Thiago Macieira - thiago.macieira (AT) intel.com
>>   Software Architect - Intel Open Source Technology Center
>>
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>>
>>
>
>
> --
> Regards,
> pritam
>



-- 
Regards,
pritam
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