[Xcb] Get RGBA image

Suhail Doshi suhail at mightycomputing.com
Tue Aug 6 01:07:04 UTC 2019


Is there a way to just get 8-bits per channel (3 or 4 channel)?

I am using an encoder that accepts 8-bit packed RGBA.

Ideally, I don’t have to do bit manipulation on my own because that will
slow things down.

On Mon, Aug 5, 2019 at 5:56 PM Alan Coopersmith <alan.coopersmith at oracle.com>
wrote:

> On 8/5/19 5:51 PM, Suhail Doshi wrote:
> > Hi there,
> >
> > I am trying out this
> > code: https://gist.github.com/Suhail/3ae62751857ff034a027adcacd350b69
> >
> > One thing I noticed is that when I print the xcb image struct info I
> don't get
> > the image size I was expecting:
> >
> > xcb_image_print() Printing a (1024,768) xcb_image_t of 1572864 bytes,
> depth: 16,
> > bpp: 16
> >
> > Do you know why ximg->size wouldn't be 1024*768*3 (3 channel: RGB)? Or 4
> channel?
> >
> > 1572864 seems like an odd size.
>
> It's the size I'd expect - 1024 * 768 * 2 (where 2 is 16 bits-per-pixel
> divided
> by 8 bits per byte).  You might have 4 bits each of RGBA or 5 bits each of
> RGB
> plus a pad bit, or some other combination of channels, in those 16 bits.
>
> --
>         -Alan Coopersmith-               alan.coopersmith at oracle.com
>          Oracle Solaris Engineering - https://blogs.oracle.com/alanc
>
-- 

Suhail

--

Founder
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