Re: 24-bit-per-pixel limit to Gdk RGB ?

[Thomas Cameron <tom ceisystems com>]

Roland Smith wrote:

> On Tue, 18 Feb 2003 17:16:33 -0300
> individual <individual mi cl> wrote:
>
>  
>
> > That's interesting. I was always under the imprsesion that we have left 
> > 24bpp displays far behind. Here's what my system says:
> >
> > Resolution        Video Memory
> >                                    8MB
> >                              (SGRAM)
> >
> > 640 x 480               32-bit
> > 800 x 600             32-bit
> > 1024 x 768          32-bit
> >    
>
> I _think_ that those 8 extra bits are for alpha blending (transparency). 
>
>  
>
> > Eek.... I was hoping for greater bit depth, but I'm getting more and 
> > more convinced that it's pointless to try and render a 48 bpp image at 
> > 48 bpp screen depth when screens are at most 24bpp deep.
> >    
>
> It's not pointless. You won't lose much quality. Consider: on a 1024*768 monitor
> you can only display 786432 different colors (if every pixel has a different
> color, which is quite rare, unless you've got some very psychedelic images)
>
> To be able to display all the colors in an 24bpp gamut, you'll need 16777216
> ((2^8)^3) pixels, which is something like 4729*3547 in traditional 4:3 ratio. If
> you come across a cheap display that can handle this, let me know. :-)
>
> Roland
>  
The format is this:

32 bit display: 8-bits RED, 8-bits GREEN, 8-bits BLUE, 8-bits ALPHA
16 bit display: 8-bits RED, 8-bits GREEN, 8-bits BLUE

This is for computer monitor displays, of course.  Personally, I have 
never heard of a 48bpp display, and I am quite certain that the human 
eye could not distinguish such a small degree of difference.  Of course, 
if you are a quality-phile, like me, you would render in 48bpp anyway.  ;-)

Good luck,
Tom Cameron