Re: question on armhf color depth
On Sunday 09 April 2017 18:58:07 Gene Heskett wrote:
> On Sunday 09 April 2017 12:09:20 Alan Corey wrote:
> > Color depth is a deep subject (couldn't resist). Different windows
> > (every X program technically has it's own window) can run at
> > different depths even right next to each other. Programs request a
> > depth from X or the window manager, not to mention a color map and
> > graphics context. If you have xwininfo (command line program so
> > it's not in menus) try it a little:
> >
> > pi2# xwininfo
> >
> > xwininfo: Please select the window about which you
> > would like information by clicking the
> > mouse in that window.
> >
> > xwininfo: Window id: 0x300008c "Gmail - question on armhf color
> > depth - Mozilla Firefox"
> >
> > Absolute upper-left X: 35
> > Absolute upper-left Y: 65
> > Relative upper-left X: 1
> > Relative upper-left Y: 30
> > Width: 1189
> > Height: 870
> > Depth: 24
> > Visual: 0x21
> > Visual Class: TrueColor
> > Border width: 0
> > Class: InputOutput
> > Colormap: 0x20 (installed)
> > Bit Gravity State: NorthWestGravity
> > Window Gravity State: NorthWestGravity
> > Backing Store State: NotUseful
> > Save Under State: no
> > Map State: IsViewable
> > Override Redirect State: no
> > Corners: +35+65 -696+65 -696-145 +35-145
> > -geometry 1189x870+34+35
> >
> > The Pi seems to make more use of a frame buffer than machines with
> > separate video cards. Devoting more RAM to the GPU in raspi-config
> > may have a little effect, I have 64 megs. A frame buffer is
> > memory-mapped video you can actually write into. fbset may show you
> > something:
>
> xwininfo reports on the windsow clicked in and since I'm logged into
> the pi with an ssh -Y profile, it dutifully reports on the shell
> window on this machine.
>
> > pi2# fbset
>
> The pi is running on a cheap AOC monitor that can only do 1366 by 780
> or some such relatively odd-ball size I had to set in the kernels
> cmdline.txt.
>
> Interestingly this 1366x768 is NOT listed by fbset! So it looks like
> I'll have to go to its console to run xwininfo, brb.
>
> Out at the pi, its 1366x768, 16 bit. The rest of it is a copy of what
> you pasted in above.
>
> I'll take a look at fbset's man page. And I think video ram is 128
> megs. Maybe I'll learn something. :)
>
> Thanks Alan.
>
Can't learn much, its xref this and xref that eventually wrapping back to
where its started without telling me anything. Every variable in those
files apparently has the ability to be set to any integer value, with no
clue whats a legal value for anything.
Enabling the video ram back to 128 megs must have changed something
because when I rebooted, the monitor reported the input was not
supported. Except when I power cycled the monitor, it came back up
looking exactly as it had been, and xwininfo still says its a 16 bit
window.
I note there's a link to a help site at the top of /boot/config.txt, so I
went thru the motions of setting it for a 1366x768, 32 bit screen. But
on the reboot it was just noticably slower, and xwininfo now says its a
24 bit screen. And the screen update rate is halved, to about 3 frames
a second. So I just commented all that stuff back out as I need the
screen update rate to be as fast as possible, it was around 6 or 7
frames a second before I started playing, and I need that more than any
so far invisible increased depth of colors. Thats not real time, but if
its the best we can do with this poor video, it will have to do until we
have a pi-4c, with 2 to 4 gigs of ram and a gpu we actually have a
driver for.
Thanks for the handholding Alan.
> [...]
>
> Cheers, Gene Heskett
Cheers, Gene Heskett
--
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