Amiga Computing - Commodore Is Awesome

pertaining to brushes (in best Rowan
Atkinson voice) known as the "Brush"
menu. Here, all the seemingly tasteless
brush warping tools are stored.
It is important to know how to use
these inside out in order to produce any
effects that may be considered original.
First, cut a new brush. It would be
advisable to make it quite large. about
200 by 100 pixels, otherwise the effects
will confuse the image. You should
paste a copy of this on to the spare
page so you can revert to it later if need
be.
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The first tool to play with has to be
the freehand resize. Everyone has used
this at sometime or other, and any
serious artist is going to need to
eventually. Try it — hold down the left
button, and move the mouse around to
change the brush to any size you want.
The mathematics of the procedure
are instantaneous, and can be very
useful in that you know what your
resized brush will look like.
Unfortunately. it usually ends up either
as a cross-section of Legoland or a
gritty mess. There is, however, a way of
getting around this.
Curiously enough, the options for this
are not in the brush menu — they are in
fact in the perspective menu, tucked
away under "extras".
First the antialias should be set to
"high" and the perspective centre
positioned in a clear area of the screen
— on the spare page if possible. You
should then select "do" from the
perspective menu — or enter from the
keyboard — and position the centre of
the brush grid over the perspective
centre.
Now use the # and ; keys to move the
brush into or out of the screen. You
must use the grid to work out when the
Figure I:
Twisting
time again
4.u2112.11 -
brush is the right size, and when it is,
slam the left (Or right!) button.
The computer draws your brush on to
the screen.
This can take up to a minute or more,
but the result is worth it. The brush
which you have just created is not only
resized with correct proportions, but
also is antialiased so that there are no
jagged lines and only a minimal loss of
detail.
Why not use this all the time? Well,
first you need some blank space to
render the brush into. This shouldn't
pose too many problems. The second,
and more pressing problem, is that you
cannot change the palette after using
this method.
The reason for this is that antialias
uses extra colours that may not
necessarily be used in the original
brush. What happens is that when two
pixels need to occupy the same space
in the resized brush DP looks at their
combined RGB values and takes the
average.
It then looks at the palette and finds
the closest colour to this, and uses it in
their place. If you then change that
colour yourself. wrongly assuming that
it's not been used. the careful blending
produced by the smoothing is ruined.
Also it's slow, and doesn't allow you to
change the shape of the brush — In
other words, it's width to height ratio
must remain equal.
Another well-used function is rotating
a brush. However, like resize, it suffers
from terminal grittiness try rotating a
stripey brush through 27 degrees!
However, there is an alternative —
employing perspective. Use exactly the
same method as for resizing, but
instead of using moving the brush along
the z-plane, try rotating around it. The
antialias will tidy up the final brush, but
it still suffers from the same problems
as resizing.
Deluxe Paint U (top)
Deluxe Paint Ill (bottom)
41111.11111
Once again all
things arty are
under the eye of
Dave Mee,
self-styled
linguistics critic
and logo vandal
In the same menu, the shear function
seems rather limited — after all, it only
works in one direction and doesn't
seem to produce anything interesting.
Its real power lies in using it to create
brushes for editing, as opposed to
creating pictures directly.
It's a tool to make other tools really,
so don't worry about not using it — it will
be explained fully 31 days from now
(assuming you buy next month's issue).
The last function, bend, is my
favourite. It is used (surprisingly
enough) to bend a brush. It is not a true
bend, as the ends of the brush remain
parallel to each other, instead of being
perpendicular to the sides.
Nevertheless, it's good fun. Let's make
the Amiga Computing logo a little more
interesting with it (Oil Leave that alone
you vandal!).
First paste the logo down. Then cut a
small vertical strip from it, choose bend
vertical, and "push" the centre of the
brush upwards.
- Paste it down somewhere, and then
do the same again with the next strip
along, but bending it downwards. Do
this until the whole brush has been
copied (second illustration in Figure II).
For a really weird touch do the same
thing again, but cut and bend horizontal
strips, alternating left and right. The
result is a markedly more interesting
brush (third illustration).
You may need
before - final presentation, but with the
addition to tidy of a small background (fourth
illustration) i t you can very easily produce
a rather impressive logo in a matter of
minutes.
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NEXT e MONTH; More brushing
up, and how to use resize and
rotate and get away with it PLUS
Dave Mee threatens to use a box!
Be there or be a rotatedlresized
polygon.
1MIGA COMPUTING November I 9g0 131