| IDL widgets: comments and questions [message #3752] |
Tue, 14 March 1995 18:30  |
knight
Messages: 37
Registered: January 1992
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Member |
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I have recently written a widget-based image viewer and have some comments
about IDL widgets. I mention some problems or lack of features I wanted.
If anybody knows how to solve them, please speak up.
1.
I wanted to add a title to each draw widget. The title keyword appears only
in widget_base. I finally used the title keyword on my plots. I'd still
like to add titles to other widgets.
2.
Control of the increment on the slider is alluded to (in The IDl Reference
Guide) for Openwindows but appears to not be available under Motif. I
wanted to bump a slider value by 1 by pressing the left mouse button, but,
whenever the slider range was large, the increment was also large. Does
anybody know how to set the increment on a slider? I know you can do it
with Motif widgets.
3.
I wanted to change the limits on a slider after it was realized. It doesn't
seem possible.
4.
As somebody mentioned recently, it would be nice to be able to know what
mouse button was pushed on an event. The widget_draw allows this with the
button_events keyword, and I used it with success. Per the recent
suggestions, one could use the diffferent mouse clicks to access help or do
alternative actions for the current widget.
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?
6.
I wanted to make some up/down or left/right arrows for incrementing and
decrementing quantities or up/down/left/right arrows for moving about on an
image. I tried a bitmap for a button but there seemed to no control over
the actual width or height of the button even though I specified a 16x16
pattern.
Are there ways to build bitmaps that take on a specified size. I really
haven't experimented here. I wonder if anybody else has.
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.
I'd appreciate answers to any of the questions above.
Thanks,
Fred
Fred Knight (knight@ll.mit.edu)
--
=Fred Knight (knight@ll.mit.edu) (617) 981-2027
C-483\\MIT Lincoln Laboratory\\244 Wood Street\\Lexington, MA 02173
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