nanogui: Images resolution
Subject:
Re: Images resolution
From:
Rosimildo daSilva ####@####.####
Date:
20 Jan 2000 19:09:22 -0000
Message-Id: <200001201858.KAA08021@www2.xoommail.com>
"Greg Haerr" wrote:
> : Is there anything I can do, to improve the resolution of an
> : image. ? I am using the "bios VGA" driver, and the image of
> : the "car" on the microwindows demo sucks big time. I guess
> : that must be some color/resolution thing that is not been
> : configured correctly.
>
> I'm not sure if your problem is pixel resolution or color resolution.
> The car will look fine at 640x480, but you've got to be running
> a 256 color palette mode, or a truecolor mode that supports
> at least about 250 colors, or the car's image will degrade.
>
> As I think about it, you're probably running RTEMS Microwindows,
> which uses the hardware scr_bios.c driver. This driver _doesn't_
> implement the setpalette() driver function, but instead runs in
> the VGA default 16 color mode. So all your colors are ugly.
> The reason this works at all is that your driver returns ncolors=16,
> and the first 16 colors of the 256 color palette basically match
> the std VGA colors, so the Microwindows color-reduction
> algorithm basically maps image colors to the right values.
>
> The fix is somewhat hard: the std VGA runs in max 640x480x16
> colors, without special programming. The extended programming
> depends on the chipset. We may need grab some libraries
> like GRX or SVGA and write special chipset-specific drivers
> to get the 256 color modes. What we really need is the GRX
> package ported to RTEMS or DOS.
>
You right. It must be color resolution. Somehow I knew that
it would not be easy. :-).
I'll try to messy around with GRX, do you have a point ?.
Unfortunately, my knowledge of graphics/chipsets is
pretty limited.
BTW, I liked the new "build structure" that you guys
came up with. I hope to get RTEMS compiling again. :-).
Rosimildo.
______________________________________________________
Get your free web-based email at http://www.xoom.com
Birthday? Anniversary? Send FREE animated greeting
cards for any occasion at http://greetings.xoom.com
