| Scrolling within a text widget [message #81302] |
Fri, 07 September 2012 12:04  |
Heinz Stege
Messages: 189
Registered: January 2003
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Senior Member |
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Hi all,
here is a very basic question on srolling the text within a text
widget. My program is writing messages (e.g. infos, warnings and error
messages) into a little text widget. I would like the widget
automatically to scroll down the text, so that the user always can
read the latest message. Here is a demo:
tlb_wid=widget_base(title='Demo',/column)
text_wid=widget_text(tlb_wid,scr_xsize=200,ysize=6,/wrap)
widget_control,tlb_wid,/realize
widget_control,text_wid,set_value='1. The first message.'
widget_control,text_wid,set_value='2. This is a message '+$
'long enough to be wrapped by the text widget.',/append
widget_control,text_wid,set_value='3. Version: '+$
string(!version,/print),/append
So far so good. However the following message will not be visible,
because the text needs to be scrolled:
widget_control,text_wid,set_value='4. Error: '+$
'Something-went-wrong-message.',/append
The user does not see this message. He can click into the text widget
and make it visible by use of the PageDown or the Ctrl+End keys.
Here is my question: How can I make my program to scroll down to the
latest message automatically?
This is what I tried by now:
1. The /TEXT_NUMBER and TEXT_OFFSET_TO_XY=integer keywords of the
WIDGET_INFO function (in combination with the
SET_TEXT_TOP_LINE=line_number keyword of WIDGET_CONTROL) do not help
because they don't consider the line breaks due to the /WRAP option
specified in the WIDGET_TEXT function. (Note that
SET_TEXT_TOP_LINE=line_number from WIDGET_CONTROL counts the lines
after wrapping.) :-(
2. The following IDL commands do the magic on my Windows OS:
big_number=2^31-1
widget_control,text_wid,set_text_top_line=big_number
However, this does not work on a Linux-OS. :-(
On Linux the text scrolls up so far, that only one line of the text is
visible. And how could I be sure, that it will still work on
Windows�8? Not to mention, that I don't know, if it works on Mac-OS.
Does anybody have a solution? Please tell me.
Heinz
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| Re: Scrolling within a text widget [message #81368 is a reply to message #81302] |
Mon, 10 September 2012 19:03  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Heinz Stege writes:
> Does that mean, that nobody writes GUIs with IDL? (I mean except the
> developers of the IDL demo.) What way do you recommend, if you have
> written an IDL program and want to give the user a GUI for starting
> and controlling the program?
I recommend you don't use a scrolling text widget. ;-)
The good news is, at least you don't have a requirement
for a table widget!
Cheers,
David
P.S. Let's just say I've found a way to write plenty of
GUIs without scrolling text widgets after I suffered so much
trying to understand them.
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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