| Re: IDL widgets: comments and questions [message #3803 is a reply to message #3752] |
Mon, 20 March 1995 09:45   |
rep2857
Messages: 28
Registered: December 1994
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Junior Member |
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In article <3k5jh1$7rb@testnews.ll.mit.edu>,
Fred Knight <knight@ll.mit.edu> wrote:
>
> 3.
> I wanted to change the limits on a slider after it was realized. It doesn't
> seem possible.
The following will work:
Widget_Control, slider_name, Set_Slider_Max=max_value
Where slider_name is the name of the slider widget to be changed, and
max_value is the new maximum value to be set.
> 5.
> On some occasions drawing a new image on a widget_draw window was funny.
> Before drawing the new image, the window was erased and the previous image
> was redrawn. Then the new image was put up. This was particularly
> noticeable when the display was a show3 or shade_surf. I don't understand
> the circumstances here; it may be due to changing windows (with wset). Has
> anybody seen this?
I don't recall seeing this in several applications I've created. However,
"erase, 0" ought to take care of the problem.
> 7.
> Some recent comments have praised the availability of the uvalue. I, too,
> use it for controlling actions in widget_control. However, I still use
> common blocks to pass most information. You can't pass the id of a widget
> via the uvalue, and I need ids whenever I call widget_control for set_value
> or get_value. So common still seems necessary, even though most information
> could be passed in the uvalue.
You can do without COMMON blocks completely in your applications and
pass around the same information with easier traceability and less
confusion using UValues. Unfortunately, the explanation is not easily
handled by email or posts. I think the best way to learn about this is
by taking one of RSI's training courses. RSI teaches the technique
during their Widget Programming classes and use several example
programs to illustrate it. Even so, I had to go back and review what
happened during class to make good use of it in my first applications
afterwards. They offer good example programs, and relevant real-world
knowledge of the language. I was very impressed with the information
that I gained from the class and the knowledge of the instructors
teaching it (Hi David F. and Molly).
Mike Schienle Hughes Santa Barbara Research Center
rep2857@sbsun0010.sbrc.hac.com 75 Coromar Drive, M/S B28/87
Voice: (805)562-7466 Fax: (805)562-7881 Goleta, CA 93117
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