Thanks for taking time to address my issue.
Francisco,
Do you know what a DirectColor visual is?
I believe so. Officially, direct color is the superset for
colormaps excluding TrueColor. Unofficially, it allows for simultaneous
usage of several colormaps, normally Xservers allow (3 simultanous
colormaps-read/write (dynamic) based on Xlib books).
Do you know why you would need a DirectColor visual?
We have a pseudo-color application in-which we update the bitmaps
using the colormap table, which are updated through mouse events. The
bitmaps are typically on the order of 1024x1024.
(Without the read/write colormaps we would have to
redraw the pixmaps everytime, too much to update. I have tried this
using TrueColor already. We can get redraw update delays on the order of
several seconds and get performance issues with X)
The problem with this program is the flickering in 8 bit mode. Most of the
window managers want to use a wide range of colors (openbox, afterstep,
etc..). To minimize the flickering, we attempt to take over the screen
and switch the Xserver and window manager to 8 bits. (We still get
flickering)
Ideally, I would like do be able to allocate a dynamic colormap without
all the flickering associated in 8 bit by running in 24 bit, thus
directcolor, and be able to do the same updates without redrawing the
pixmaps as we currently do.
Actually, I would be satisfied, if the XFree86 running 24 bit True color
would have a 8 bit pseudocolor visual available and be reported by
xdpyinfo. Then I could match the visual and be happy..:)
--I am not sure how to enable backingstore with cygwin/XFree86 either.
Do you know of any Windows-based graphics cards that actually support
DirectColor?
--Actually, I do not know. I have only seen DirectColor visuals reported
on some of the emails on the internet by searching directcolor xfree86
My understanding of DirectColor is that it allows you to specify the
range of colors that will be used in a mode that is similar to TrueColor...
however, I don't know of a single Windows graphics card that allows you
to do that. I don't know of any program that utilizes such a visual either.
As such, there is no support for DirectColor in Cygwin/XFree86. I don't
expect that there will ever be DirectColor support in Cygwin/XFree86
unless someone can explain to me that I am way wrong.
DirectColor seems like a lot of things in X: it was thought to be REALLY
useful when X was designed, but it turned out to be anything but useful.
I read about those things once, then I ignore them after that.
So, anyone else know what DirectColor is?
Harold
So inconclusion, DirectColor is not available to cygwin/XFree86 ?
Are there cases where I can run TrueColor and have a pseudocolor visual
available with/or without a different graphics card. I'll buy one ?
Thanks again for your time.
Francisco Rojas
Electrical and Computer Engineering Department
University of Arizona, Tucson, Arizona
OFFICE: ECE 408, 520.621.4554
FAX : 520.621.8076
On Mon, 13 Jan 2003, Francisco Rojas wrote:
I am running the lastest cygwin and xfree86.
In 24 bit mode, I only get the TrueColor Visual.
What I do I need to do to get a DirectColor Visual
listed using xdpyinfo ?
Currently, I am running a NVIDIA Gforce2 400?
If I need to change videocards what are the recommended cards?
I have not seen anything in the documentation or mailing lists.
$ xdpyinfo
name of display::0.0
version number:11.0
vendor string:The XFree86 Project, Inc
vendor release number:4020
XFree86 version: 4.2.0
maximum request size: 4194300 bytes
motion buffer size: 256
bitmap unit, bit order, padding:32, LSBFirst, 32
image byte order:LSBFirst
number of supported pixmap formats:7
supported pixmap formats:
depth 1, bits_per_pixel 1, scanline_pad 32
depth 4, bits_per_pixel 8, scanline_pad 32
depth 8, bits_per_pixel 8, scanline_pad 32
depth 15, bits_per_pixel 16, scanline_pad 32
depth 16, bits_per_pixel 16, scanline_pad 32
depth 24, bits_per_pixel 32, scanline_pad 32
depth 32, bits_per_pixel 32, scanline_pad 32
keycode range:minimum 8, maximum 255
focus: window 0x42, revert to PointerRoot
number of extensions:21
BIG-REQUESTS
DEC-XTRAP
DOUBLE-BUFFER
Extended-Visual-Information
FontCache
GLX
LBX
MIT-SUNDRY-NONSTANDARD
RECORD
RENDER
SECURITY
SGI-GLX
SHAPE
SYNC
TOG-CUP
XC-APPGROUP
XC-MISC
XFree86-Bigfont
XKEYBOARD
XTEST
XVideo
default screen number:0
number of screens:1
screen #0:
dimensions:1274x961 pixels (431x325 millimeters)
resolution:75x75 dots per inch
depths (7):24, 1, 4, 8, 15, 16, 32
root window id:0x36
depth of root window:24 planes
number of colormaps:minimum 1, maximum 1
default colormap:0x20
default number of colormap cells:256
