
WinEarth Readme


Copyright (c) 1997, 1998 Joachim Feise. All Rights Reserved. 

http://www.ics.uci.edu/~jfeise/
email:jfeise@ics.uci.edu

Ported from xearth. Copyright (c) 1989-1990, 1993-1995 Kirk Lauritz Johnson.
Portions Copyright (c) 1989-1991 Jim Frost.
Portions Copyright (c) 1992 Jamie Zawinski.
Portions Copyright (c) 1996-1997 Microsoft Systems Journal (Paul DiLascia).

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DISCLAIMER

Permission to use, copy, modify and freely distribute WinEarth for
non-commercial and not-for-profit purposes is hereby granted
without fee, provided that both the above copyright notices and this
permission notice appear in all copies and in supporting
documentation.

The author makes no representations about the suitability of this
software for any purpose. It is provided "as is" without express or
implied warranty.

THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT
OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

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---- Contents ----

	Introduction
	Installing WinEarth
	System Requirements
	Documentation
	Source Files
        Revision History
	Known Problems and Limitations


---- Introduction ----

Thank you for using WinEarth, a program that draws an image of the earth
as seen from space on the background of your computer screen.


---- Installing WinEarth ----

The setup program makes it easy to install WinEarth onto your system.
You run the setup program by choosing Start menu - Run, then entering
"a:\setup". Follow the instructions on the screen.


---- System Requirements ----

WinEarth is a 32-bit application. It runs on Windows 95 and
Windows NT 4.0.

The full WinEarth installation requires approximately 1.2 MB of disk
space.


---- Documentation ----

Currently, WinEarth does not include a help file, although it is intended
to eventually provide one.
Therefore, the only "documentation" available at this time is in the form
of the source files, which can be installed together with the binary files.


---- Source Files ----

The installation program optionally installs the WinEarth source files into
the source directory below the selected program directory.
The source files compile with Microsoft Visual C++ 5.0. Included with the
source files is a Visual C++ 5.0 workspace file.
Comments in the source files are rather sparse, so a thorough understanding
of the source code is required before any changes are attempted.


---- Revision History ----

1.02 Bug Fix Release
    1. External marker files are now recognized correctly. A sample marker file,
       MARKERS.MRK, is provided in the WinEarth directory.
    2. The Timewarp functionality is now guarded against calculation overflows.
    3. The Shift editfields now accept values from -1024 to 1024.
    4. Dithering is now available in High Color and True Color modes.
       The default coloring modes are:
         in color modes up to 256 colors, dithering is enabled
         in High Color and True Color modes, all available colors are used.
       If the default mode is switched off, the image is dithered with
       the number of colors selected in the edit field.
       Best values are achieved with 64 colors.
       Note that without dithering in High Color and True Color modes,
       circles may be observed with an apparently wrong color gradient,
       i.e., the circles appear to be darker towards the sun position.
       However, this is just an optical illusion. In fact, within each circle
       only one blue or green color value is present. Dithering with 64 colors
       causes the circles to disappear, resulting in a smooth image.
    5. The Aboutbox now contains an animated icon, which also serves as a hotlink
       to the author's Web site (many thanks to Paul DiLascia and his C++ column
       in MSJ). Also added are a text link to the author's Web site and an email
       link.


1.01 Initial Release


---- Known Problems and Limitations ----

The following is a list of known problems and limitations with WinEarth:

1.  The colors can be incorrect when in 256-color mode, and another application
    uses a lot of colors.
    The next WinEarth screen update automatically restores the correct colors.

2.  On rare occasions, the Windows 95 shutdown can cause WinEarth to exit
    abnormally. The author has this seen happen only once, and it was not
    repeatable, so it is unclear at this time what caused this behavior.

3.  Currently, WinEarth does not provide facilities to calculate an image and
    write it to a GIF or PPM file (which is a nice feature of xearth).

4.  WinEarth uses two memory bitmaps to prepare the background image. On
    systems with high resolution graphics cards and small amounts of main
    memory this design might lead to extensive swapping.

5.  As mentioned above, there is no help file yet. A click on the help button
    brings up the Aboutbox.

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Last Updated: Saturday, January 10, 1998
