Category : Alternate Operating Systems - Quarterdeck DesqView, CP/M, etc
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Filename : XVIDEO.TEC

 
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ID:XV DESQview/X: Configuring the Display Server
Quarterdeck Technical Note #256 Filename: XVIDEO.TEC
by Eduard Marghidan CompuServe: XVIDEO.ZIP
Last revised: 8/25/92 Category: DVX

Subject: Configuring the video display options in the DESQview/X Setup
program, a discussion of DESQview/X's support for video chipsets, and
other video issues.


The display server handles video display for DESQview/X. A variety of display
options can be set with configuration and setup files.

DESQVIEW/X SETUP

By running Desqview/X's "setup" program (Go into the DVX directory and type
"setup", then hit the "enter" key) both the DISPLAY MODE and WINDOW MANAGER
options allow you to make a variety of video display modifications. Choose
the advanced setup option.

The DISPLAY MODE option allows you to choose a variety of resolutions and
number of colors displayed on the screen. Which options you can choose
depends on the ability of your video adapter hardware; which options you may
wish to choose depends on performance considerations, for higher resolutions
and a greater number of colors require more time and memory to draw the
screen.

The WINDOW MANAGER option provides selections for the windows' and menus'
attributes and functionality. Windows are displayed in one of nine
predesignated positions on the screen which can also be changed in the setup
program.

You are also able directly to change the Window Manager or DESQview/X
configurations by editing dvx.cfg, screens.txt, and rgb.txt. This should only
be done if you want to bypass the setup program, which is a better tool at
modifying those configurations.

DISPLAY SETUP

This submenu allows these parameters to be changed:

D Display Mode VGA 640x480 16-color
S Screen Size 12 inches (300mm)
V Virtual Screen no
B Background solid ( 85 85 85)
A Screen Saver off
F Font Path misc, 75 dpi, atm
O Other B

"Display Mode" allows you to choose the pixel and color resolutions that the
display server can use.

"Screen Size" is used by X programs to determine a default font that uses your
display capabilities best.

"Virtual Screen" allows you to have a logical screen that is larger than the
physical screen, the physical screen scrolling over the logical screen when
cursor movement goes beyond the boundary of the physical screen currently
displayed. Your virtual screen can be as large as 256K when you use a
16-color server, and as large as 1024K (if you have a one megabyte video card)
when you use a 256-color server. The height and width can be no less than the
respective height and width of the chosen display mode. With a 16-color
server in the 640x480 mode your virtual screen can be as tall as 1088x480, as
wide as 640x819, or any other pair of numbers whose product is no greater than
524,288 (=512K) (But you cannot have a height less than 480 or a width less
than 640). For example, 16 colors requires 4 bits per pixel to define the
color, so one byte accommodates two pixels and 256K memory accommodates
524,288 pixels in 16 colors.

With a 256-color server in the 1024x768 mode your virtual screen can be as
tall as 1360x768, as wide as 1024x1024, or any other pair of numbers whose
product is no greater than 1,048,576 (=1024K=1 MEG). In this case, 256 colors
requires 8 bits, or one byte, per pixel, so 1024K of memory accommodates
1,048,576 pixels in 256 colors. For this display mode your selected height
must be at least 768 and your width cannot be less than 1024.

"Background" gives you the option of selecting a background color or pattern
for start up. There is also an executable backdrop.exe file that allows the
user to change backgrounds while running DESQview/X.

"Screen Saver" allows you to put a moving logo curtain or a blank curtain over
your applications after a preset time period.

"Font Path" is a path default for the server to look for fonts.

"Other" is a submenu that gives these options:

B Backing Store yes
G Grey Visual no
S Static Visual no
8 Depth 8 Visual no

"Backing Store" is by default enabled only for X applications that request
this service from the X server. Certain X applications will use code that
enables them to request this service from the server. This function is not
uncommon with X programs that overlap menus or windows. By using the server's
capability of "backing" some of the program's displayed information, the
display server caches the application's buffers for storing those special
windows. Setting it to "always" may not be a speed improvement, unless the
program is running slow display code, and it uses up server memory.

"Grey Visual" should be chosen for VGA or EGA monochrome displays. It will
allow programs that allocate any colors to display in shades of gray.

"Static Visual" may be needed if the X application is changing palettes often,
or if it's allocating private palettes. Normally, the X server will allocate
colors dynamically and reallocate them as needed. Some X programs may need to
allocate private colors that cannot be allocated to any other application.
Use this option only with X applications that require a special set of colors
to be pre-defined. This option may affect the look of X applications on a
256-color setup.

"Depth 8 Visual" sets up a pseudo-color map on a 16-color server for X clients
that require a 256-color setup. Standard X clients will not require this
option. If you are already using a 256-color server, this option will not do
anything.

WINDOW MANAGER

This option in the setup program allows you easily to change display
characteristics, the following menu lists the options available

M Mouse button usage
H Hotkey usage
C Color usage
W Window positions
F Frame appearance
T Text Font

Relating to video handling, these options can be used:

"Color Usage" lets you customize the colors for window frames and menus.

"Frame Appearance" contains the defaults for the window appearance and
handling by the DESQview/X window manager. By default, all of its features
are enabled.

The other options are defaults for the windows such as:

"Window Positions" allows you to change the nine predesignated areas on the
screen in which programs open.

"Text Font" allows a different proportional font to be used for title bars and
menus.

The display server provided with DESQview/X is configurable for a variety of
different video hardware. The options for configuration are stored in these
files:

In the \DVX\SERVER subdirectory:

SCREENS.TXT (video hardware supported)
RGB.TXT (names of colours available)
XB/XC16.VMC (display server memory)

In the \DVX directory:

DVX.CFG (start-up options for DESQview/X)

If you wish to use a different video mode for the display, you can modify
DVX.CFG with the setup program, which looks at the card's BIOS to
determine what video processor it uses. The TYPE line will be VGA for
the low resolution server and VG8 for the high resolution server. It
also contains a line which defines the video mode for the display server.
For example, screen 800x600:2029h configures the display server for 800
by 600, video mode 29h, for a card whose video processor chip number is
20 (ET 4000).

This file should only be manually modified when setup does not see the
video chipset as supported and there is some strong similarity between
that video processor and a known card's video processor. You can modify
this file directly with an ASCII text editor. You can get valid lines
from SCREENS.TXT. If DESQview/X does not detect a video chipset's
ability to display in a specific mode, changing DVX.CFG to make it try to
make DESQview/X use that mode may cause DESQview/X to display incorrectly
or not at all.


WM.CFG (colour configuration for the window manager)

This text file is a resource file for the DESQview/X window manager. The
window manager can be configured through the setup program, rather than
manually editing this ASCII file. Check the README.DWM file for specific
information relating to the Window Manager commands. The file also
contains color names for the menus, frames and highlights. The color
names and their corresponding RGB values can be viewed in the RGB.TXT
file in the \DVX\SERVER subdirectory.


SCREENS.TXT Available video support

This file lists the supported video chipsets and the specific modes that
each BIOS can use under DESQview/X. The first seven characters define
display resolution. The first two characters of the second segment
represent the video chipset type. The second two characters represent
the mode a video card will use. If your card is not on this list, you
can try modifying DVX.CFG to extend 256-color support for your card,
by checking SCREENS.TXT. You would have to know of a supported card
that uses the same video processor, and use that entry number to denote
the unsupported card's VGA chip and video mode. For example, a Paradise
card with an undetected WD90C00 processor may use the following line:

VGA 800x600:3058h

The line comes from SCREENS.TXT, which lists that as a supported WD90C00
mode. However, if the video processor was not detected, it might be an
older BIOS revision which is different from the supported chip.


RGB.TXT Colour definitions file

At the top of this file there are 16 colours defined for window and icon
color attributes. Subsequently, there are 738 pre-defined color names
that are available to the display server configured for 256 colors. Any
of these colours may be changed, although the X standard will assume the
default settings. All the X applications will allow the user to specify
custom colours for that particular client at start-up. For example,
entering "clock -fg PcGreen -bg PcRed" will start the clock program with
a green foreground and a red background.

XB16.VMC 16 colour configuration
XC16.VMC 256 colour configuration

These files allocate a maximum amount of memory for the display server.
The line maxmem=1000 indicates that value in kilobytes. Normally, the
window manager does not save the video screens for each application
hidden under other windows. However, the virtual memory set for the
server set with "maxmem" may be too low for running multiple sessions,
and the server will swap the video and memory buffers out to disk. If
the display speed is too low when running a number of windows, try
increasing that value to 1600 or 2000, or even 3000 for a 256-color mode.
If that amount of RAM is not available after opening all the
applications you will need to run setup and choose a lower resolution.
The maximum value is not taken out of RAM all at once, as the server will
allocate it dynamically.


EGA USAGE

The EGA adapters that are supported at this time will translate the color
palette into their registers somewhat differently than the VGA colors.
For this reason some colors may be darker and less readable. For DOS
windows this can be changed by loading DVANSI and using an ANSI command
to offset the default color to something more readable. For example
this command enables blue text on cyan:

ECHO 

The character before the left bracket is ESC, or decimal 27. Your batch
editor must be capable of storing this character in the batch file.
Check your DOS reference manual for different colors' settings.

MONOCHROME USAGE

Most monochrome high resolution display users will benefit from using the
"Grey Visual" display option in setup. If setup is not displaying
properly, setup should be run with the /M parameter. DESQview/X does not
currently support Hercules or CGA displays.


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* Copyright (C) 1992 by Quarterdeck Office Systems *
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