| Object graphics - some questions [message #11283] |
Sun, 29 March 1998 00:00 |
Neil Conway
Messages: 1
Registered: March 1998
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Junior Member |
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(Can't find a FAQ for this group in news.answers, am I looking in the
wrong place ?)
I have just found a reason to use IDL 5's object graphics system. I
read the manual, liked the bit about objects in general, then read the
bit about the graphics objects and then my pleasure started to
diminish very rapidly.
My worries were soon to become disbelief. Unless I have grossly
missed the point, object graphics is a dog, and cannot replace many
functions of direct graphics.
I'd love someone to show me a way to do what I expected to be able to
do 'out of the box' with object graphics... Here are the some of the
problems I have hit already:
1. I use an 8-bit display, and almost all the X-terminals around my
business are also 8-bit. When one brings up an object graphics
(henceforth OG) window it takes (by default) nearly all the available
colours to build an RGB map. When a second window comes up, it takes
all the rest. I have found an option to use the indexed colour model,
but it appears that each separate OG window uses a separate colour
map, and thus one is doomed to have either very few colours per
window, or the dreaded colour-map switching. OK, I could get around
this by using 24-bit displays only (not an option for me, sadly).
2. When preparing output for a printer, incredibly, there appears to
be no programmatic way to specify a given output device. Rather, one
must use a dialog and ask the user to pick one. Furthermore, the
range of output devices seems not to include the likes of CGM files,
but just kosher print devices. Did I miss something here ?
3. Using (for example) the postscript output ("EPSF" output, but it's
not encapsulated), I was horrified and bemused to discover that a
simple sine-wave (the "simple plot" from the manual) uses up 200kB of
disk space, because (brace yourself) it's written as a BITMAP (!?!?).
I simply can't get my head around that one.
Please tell me that I've been dreaming, and that all of these are
surmountable problems... If not, then dOG will be stuck in its kennel
for the foreseeable future in my books.
Neil Conway
UKAEA Fusion
neil.conway@ukaea.org.uk
(Email copies of followups appreciated, our proxy server is another
dog and thus getting to a news server is very traumatic)
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