info-mac@uw-beaver (01/18/85)
From: Karney%PPL@LLL-MFE.ARPA
Tekalike (Version 1.1, from Mesa Graphics, price $250):
This is a Tektronix emulator, supporting zooming, color printing (not
tested). There is no VT100 support or similar capability. No file
transfer (except for capturing plots) is supported.
Plotting and zooming all work as advertized.
In order to zoom on a plot you have to select start recording, make the
plot, stop recording, and finally zoom on recording. This is is very
clumsy. There should be a circular buffer of the last n plots, together
with a way of writing a particular frame into a file.
There is no way of panning except by going back to the full plot. And
the way of doing that (with a backwards zoom window) is kludgey.
Tektronix 4016 vectors are recognized. This allows the vectors to be
specified in a 4096 * 4096 square (about 50% overhead on transmission).
This enables small vector characters to be blown up.
The "Tekalike" screen has the same aspect ratio as a Tektronix so
squares stay squares. However, this property is not maintained when
zooming.
Often, there are errors in the transmission of characters from the Mac
to the host computer, especially when typing fast. This could be a
problem with the modem, but I suspect Tekalike.
When a plot is played back, the beginning is often garbled (as though
it dropped the first few characters in the recording). When the plot
was originally made there were no problems. The problem is repeatable.
I.e., playing back again doesn't help.
There should be a way to abort a zoom when you realize you have placed
the first corner incorrectly. Note however that you can interrupt the
zoomed replotting by just asking for another zoom.
Playback and zooming is only 2-4 times faster than the original
plotting (at 1200 baud). This is because it always reads from disk.
(Presumably this is better with the RAMdisk.) It should keep the
current plot in memory and zoom it at lightning speed. Even if it
doesn't do this, it should keep the full sized plot around as a raster
image in memory, so that can be instantly redisplayed (together with
the current zoom window).
Zooming doesn't blow up the hardware characters (should it?).
You can't generate some control characters (^@, ^^, ^_) as far as I can
tell.
There should be a menu giving the correspondence between the shading
patterns and the colors.
It should allow you to make a 8 * 10 in hardcopy of the plot. (This
would allow you to see the whole plot at Tektronix 4010 resolution.)
I would say these guys have done a minimal job. They give you
zooming and that's it. And they haven't done that particularly well.
There are lots of ways in which the zooming could have been made
easier. (E.g.: Have an inset with the full plot and the zooming
rectangle shown. Allow specification of the zoom window in the inset,
and so permit a larger zooming rectangle to be chosen. Use a hand
grabber to move a constant sized zooming rectangle around a la
MacPaint.)
This is a $25 value selling at an outrageous $250. Don't buy it.
---Charles Karney (Karney%PPL@LLL-MFE.ARPA)
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