Most vehicles within the program BAHNLAND are still drawn with the
16 standard colors of WINDOWS. Mixed colors are realized as raster colors
(checkered patterns consisting of two or more colors). This restriction was
necessary at the time BAHNLAND was written to support graphics cards with 256 or
less colors. If different pictures were shown at the same time, where the total
number of colors exceeded the limit of 256 colors supported by the graphics card,
the colors were falsified. Therefore, the following restrictions apply for
designing pictures for the program BAHNLAND:
Landscapes derived from a photograph normally consist of more than 16 colors.
In most cases, it is possible to reduce the number of colors to 256 (including the
16 standard colors of WINDOWS) without loss of too much quality (see the
example "Gondrellplatz" in the list of the BAHNLAND landscapes). All vehicle
drawings, which are restricted to the 16 standard colors, can be combined
freely with such pictures without risk of color falsification.
In Version 3.0 of the MM+MM screensaver of Manfred und Martin Meyer, every vehicle
drawing is still restricted to 16 colors but not necessarily to the
standard colors of WINDOWS. In this way, there are more real colors available to
reproduce the originals without any need of more file space. The complete number
of colors, which was used until now for all vehicle drawings for the MM+MM
screensaver, is still less than 256 as shown in the color palette on the left.
Therefore, there is no danger of false colors with 256 color graphics cards
when running the MM+MM screensaver.
However, combining these vehicles with landscape drawings, where the number of
colors to be displayed exceeds 256, will lead to inevitable color falsifications
when using 256 color graphics cards.
Using graphics cards with 16 million or 65000 colors (true color or high
color), there is no danger of color falsifications or they are hardly visible with
our eyes. Accordingly, each user has to decide under these points of view, whether
to use only the 16 standard WINDOWS colors or the full color range when
drawing vehicles for the MM+MM screensaver and for the program BAHNLAND.
Independent of the type of graphics card, different amounts of memory or disk space
are needed for the same bitmap depending on the color depth used. A bitmap with
58 x 200 (=11600) Pixels needs:
- 6 KB if bitmap is based on a 16 color palette
- 12 KB if bitmap is based on a 256 color palette
- 36 KB if bitmap has true color format