| Cursor Position with Draw Widget [message #3090] |
Wed, 02 November 1994 12:33  |
ganga
Messages: 4
Registered: November 1994
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Junior Member |
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Hi,
I'm trying to figure out how to return the cursor position from an
event in a draw widget. I want the coordinates to be in data
coordinates. This seems to be possible for a regular graphics window
through the cursor command, but I can't figure out how to do it within
a draw widget as the documentation says not to use the cursor command.
Any help would be appreciated. Thanks,
Ken
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| Re: Cursor Position with Draw Widget [message #3091 is a reply to message #3090] |
Thu, 03 November 1994 09:47  |
8015
Messages: 52
Registered: November 1993
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Member |
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In article <398t20$6im@agate.berkeley.edu>, Ken Ganga <ganga@physics14> wrote:
> Hi,
>
> I'm trying to figure out how to return the cursor position from an
> event in a draw widget. I want the coordinates to be in data
> coordinates. This seems to be possible for a regular graphics window
> through the cursor command, but I can't figure out how to do it within
> a draw widget as the documentation says not to use the cursor command.
>
The event returned from clicking in a draw widget contains an X and Y
parameter. You should be able to access it through event.x and
event.y. Here's a line from one of my applications that handles the
data conversion, also:
ll = convert_coord(event.x, event.y, /device, /to_data)
In this case it is converting the device coordinates to data
coordinates from a map projection. A few lines later, the following
commands put lat and lon coordinates in strings:
latstr = 'Lat: ' + string(ll(1), format='(F12.2)')
lonstr = 'Lon: ' + string(ll(0), format='(F12.2)')
Hope that helps,
Mike Schienle Hughes Santa Barbara Research Center
8015@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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| Re: Cursor Position with Draw Widget [message #3097 is a reply to message #3090] |
Wed, 02 November 1994 20:04 |
rivers
Messages: 228
Registered: March 1991
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Senior Member |
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In article <398t20$6im@agate.berkeley.edu>, ganga@physics14 (Ken Ganga) writes:
> Hi,
>
> I'm trying to figure out how to return the cursor position from an
> event in a draw widget. I want the coordinates to be in data
> coordinates. This seems to be possible for a regular graphics window
> through the cursor command, but I can't figure out how to do it within
> a draw widget as the documentation says not to use the cursor command.
>
You can get the cursor position in DEVICE coordinates and then convert to DATA
coordinates with:
result = CONVERT_COORD(x, y, /device, /to_data)
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| Re: Cursor Position with Draw Widget [message #3099 is a reply to message #3090] |
Wed, 02 November 1994 15:56 |
scott
Messages: 17
Registered: January 1994
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Junior Member |
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Ken Ganga writes
> Hi,
>
> I'm trying to figure out how to return the cursor position from an
> event in a draw widget. I want the coordinates to be in data
> coordinates. This seems to be possible for a regular graphics window
> through the cursor command, but I can't figure out how to do it within
> a draw widget as the documentation says not to use the cursor command.
>
> Any help would be appreciated. Thanks,
>
> Ken
You get the coordinates directly from the event structure returned when
the user clicks in the Draw Widget. They are in event.X and event.y, in
device coords. To get the coords in data coords, do the following:
coords = CONVERT_COORD(event.X, event.Y, /DEVICE, /TO_DATA)
See page 1-340 of the IDL Reference Guide (v. 3.6.1) for more info, or
feel free to email me.
--
A. Scott Denning (303)491-8346
<scott@abyss.atmos.colostate.edu>
Dept. of Atmospheric Science
Colorado State University
Fort Collins, CO 80523
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