| Re: undocumented IDL built-in TVRDC [message #2297 is a reply to message #2296] |
Thu, 09 June 1994 19:16  |
gurman
Messages: 82
Registered: August 1992
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Member |
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In article <1994Jun9.182922.21061@noao.edu>,
eharold@corona.sunspot.noao.edu (Elliotte Harold) wrote:
> I recently ran across what appears to be an undocumented built-in
> procedure in IDL 3.5 called TVRDC. I can't find a reference to it anywhere,
> but it seems to return the point in the IDL window which the user
> clicked. It's syntax is
>
> tvrdc,x,y,/dev
>
>
> After calling this x and y now contain the x and y coordinates where the
> mouse was clicked. Here at NSO we found it useful for a program that
> tracks Jupiter's moons between frames. In the picture of Jupiter taken
> with the Vacuum Tower Telescope the moons are fairly small, pretty much
> single pixel objects so to locate them we just move the mouse and click
> on the moon. Has anyone else used this? More to the point is there some
> reason it's undocumented? Or is it documented somewhere that I just haven't
> been able to find? If you're wondering how I found out about it, I saw it
> used in the TVRD userlib procedure.
TVRDC certainly used to be documented (at least way back in the IDL < 2
days), but it may be (rank speculation here) that not every platform that
now supports IDL also supports cursor readback.
It's:
TVRDC, x, y [, wait_for_mouse_button]
where wait_for_mouse_button non-zero (default) means: wait 'til mouse is
clicked to read back x and y. If wait_for_mouse_button is 0, it executes
immediately.
Keywords can be one of (at least): /device, /normalized, and /data.
Anybody from RSI care to indicate why TVRDC is undocumented? Or are you
all too busy preparing for the release of IDL 3.6? Or selling ENVI
licenses?
Joe Gurman
--
Joseph B. Gurman / NASA Goddard Space Flight Center/ Solar Data Analysis
Center / Code 682 / Greenbelt MD 20771 USA / gurman@uvsp.gsfc.nasa.gov
| Federal employees are still prohibited from holding opinions while at |
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