| Re: IDL 5.2 GUI Builder Tutorial ? [message #15624 is a reply to message #15556] |
Thu, 27 May 1999 00:00   |
rmlongfield
Messages: 68
Registered: August 1998
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Member |
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Hi Karl and all,
I haven't seen the GUI tool but when I first started with widgets, I
used WIDED, which I thought was useful at least in getting used to
widgets and how the programs should look. I also found it useful in
learning how to position items ON the screen. The connection of bases
and subbases and buttons and draw windows was very confusing.
This tool helped in this respect. It was also useful, as was mentioned,
in getting used to the proper syntax of a WIDGET definition.
I must, however, agree with David when it comes to actually using the
resulting program to do something. I recall putting print statements in
the event handlers so that at least I could find out where the program
went when I pressed on a button.
In article <MPG.11af0de4659f2d9897b3@news.frii.com>,
davidf@dfanning.com (David Fanning) wrote:
> Karl Young (kyoung@itsa.ucsf.edu) writes:
> ---about the GUI Builder ---------
> But, of course, the code doesn't *do* anything. All the
> event handlers are stubbed out "shells", there are no
> positional or keyword parameters defined to get data into
> the program, no provision for passing information around
> in the widget program, etc. Oh, oh. Bad news here. You
> are going to have to learn some widget programming anyway
> or you aren't going to be able to get any but the
> very simplest programs to work!
The biggest "paradym shift" (as I would call it, if only I could spell
it right) was the understanding that the flow of a program was no longer
from top to bottom. The main program code, which defines everything,
ran from top to bottom. This makes the widget window that appears on the
monitor. But the "action", the things that you want to happen, all
are located in the event handler code, which had to be placed ABOVE the
main program. This part was not included in WIDED and I suspect it
isn't in the GUI either.
The simplest widget I have is one that draws an image and has a delete
button on the bottom. This I can write in five minutes. (After about a
year of learning IDL and widget programming, but I am pretty slow, I
think). I got sidetracked badly with compound widgets, though others
find them easy, it seems. Learning to use the UVALUE was also a major
achievement (here's where David's book was particularly handy).
Do a widget search on this group. There's lots of stuff.
Anyhow, good luck!
Rose
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