[Qt-interest] Adding arbitrary depth to Graphics Scene & Friends

[Jason H]

If it were me, I would probably look into just making an arbitrary BPP 
QPaintEngine. 

For using QGraphicsView for rendering your scene, you'd use that device. 
You'd give it a member function of setDataPixelDepth(int bpp), and it would do 
the pixel math in whatever precision is needed. Then a setViewPixelDepth(int 
bpp) which would convert from the data depth to the view depth.

You should be all set from there, as QGraphicsItems use QPaintEngines.








________________________________
From: Javier Urien <javierurien at gmail.com>
To: Jason H <scorp1us at yahoo.com>
Cc: qt-interest at trolltech.com
Sent: Tue, April 26, 2011 11:27:09 AM
Subject: Re: [Qt-interest] Adding arbitrary depth to Graphics Scene & Friends




On Tue, Apr 26, 2011 at 12:03, Jason H <scorp1us at yahoo.com> wrote:

Let me ask this. Is everything in your scene high BPP?
>

No. Input may be, but output should be both HBPP or RGB(A). Of course, HBPP 
output without HBPP input sounds ilogical, but it should be possible too.
 

>
>If so, why not?
>

To answer this let me go back to the purpose of the application I am trying to 
build. 
The app is a raster processing application, not to confuse with image processing 
although they have a lot in common. I think it is safe to say that image 
processing is a subset of raster processing.
I have to ingest arbitrary depth and data type images, apply some processing 
over the geometry or the digital values of the images and the output might be 
the screen, an RGB image (here same as screen) or a HBPP image. In the first 
two, the result would be lowered down to representable data as a final step. But 
for HBPP I want to get all the processing and keep it HBPP.
Also, I may need vector entities rendered in (A)RGB or in greyscale replicated 
over every channel of the HBPP data.
Apply geometric transformations (non-affine) to the HBPP and get a rendered 
scene on an HBPP output (file) or RGB (screen).
Use masks during the processing.

I think I can benefit from GS and GV. The objectives are that if I can see it on 
screen, I can get it on disk and I can see the lowered BPP versión of all 
everything I can get.

Please let me know if there is something not clear enough, English is not my 
mother language and I am really getting a lot from your answers.

Thanks.
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