| Re: draw widgets and programming [message #4505] |
Wed, 14 June 1995 00:00 |
knighton
Messages: 12
Registered: June 1995
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Junior Member |
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In <CHARLES.95Jun12140540@omcen.berkeley.edu> charles@omcen.berkeley.edu (charles bartels 515) writes:
> Hi,
> I'm currently trying to write a widget program using the widget
> builder. I had no problem actually getting the template of the widget
> made. What I'm having trouble with is connecting the program to the
> widgets. Specifically, having a "button press" event wset to a draw
> widget and then plotting some data. The widget *.pro contains the
> lines:
> COMMON DRAW5_Comm, DRAW5_Id
> WIDGET_CONTROL, DRAW5, GET_VALUE=DRAW5_Id
> when the button event is pressed I tried to
> wset, DRAW5_Id
> etc...
> but that didn't work at all. IDL said that the variable "DRAW5_Id"
> was undefined.
> Does anyone know what the problem is?
I fired up the widget builder and created a base with only a draw widget. The
following code was produced:
PRO MAIN13_Event, Event
WIDGET_CONTROL,Event.Id,GET_UVALUE=Ev
CASE Ev OF
'DRAW2': BEGIN
Print, 'Event for DRAW2'
END
ENDCASE
END
PRO test, GROUP=Group
IF N_ELEMENTS(Group) EQ 0 THEN GROUP=0
junk = { CW_PDMENU_S, flags:0, name:'' }
MAIN13 = WIDGET_BASE(GROUP_LEADER=Group, $
COLUMN=1, $
MAP=1, $
TITLE='Test', $
UVALUE='MAIN13')
DRAW2 = WIDGET_DRAW( MAIN13, $
BUTTON_EVENTS=1, $
MOTION_EVENTS=1, $
RETAIN=0, $
UVALUE='DRAW2', $
XSIZE=100, $
YSIZE=100)
WIDGET_CONTROL, MAIN13, /REALIZE
; Get drawable window index
COMMON DRAW2_Comm, DRAW2_Id
WIDGET_CONTROL, DRAW2, GET_VALUE=DRAW2_Id
XMANAGER, 'MAIN13', MAIN13
END
It looks like the event handler (MAIN13_Event) doesn't have the common block
DRAW2_Comm which is defined in the widget definition procedure (test). This
means that when an event occurs and the event handler is called, the window
id DRAW2_Id is not defined. In IDL all variables are local unless they
are exported through a common block or are system variables.
Try putting the statement:
COMMON DRAW2_Comm
in the event handler. Or better yet, simply call a procedure from the event
handler to perform the desired action and put the common block in that procedureinstead.
I hope that this helps.
Ken Knighton
General Atomics, Fusion Division
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