| Re: undocumented IDL built-in TVRDC [message #2264] |
Mon, 13 June 1994 12:51 |
velt
Messages: 19
Registered: June 1994
|
Junior Member |
|
|
In article 21061@noao.edu, eharold@corona.sunspot.noao.edu (Elliotte Harold) writes:
> 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.
>
> --
>
> Elliotte Rusty Harold National Solar Observatory
> eharold@sunspot.noao.edu Sunspot NM 88349
It appears that tvrdc has similar functionality as cursor. When I first read
your message it appeared that you could retrieve the *last* cursor position
where the mouse was clicked, which would have great advantages over the
current routines, that read the cursor postion *after* the routine is called.
Tvrdc is a fossil from IDL version 1. The IDL users guide VS 2.1 (1991) describes
the differences between cursor and tvrdc.
Robert Velthuizen
velt@rad.usf.edu
|
|
|
|
|
|
| Re: undocumented IDL built-in TVRDC [message #2292 is a reply to message #2283] |
Fri, 10 June 1994 04:33  |
thompson
Messages: 584
Registered: August 1991
|
Senior Member |
|
|
gurman@uvsp.gsfc.nasa.gov (Joseph B. Gurman) writes:
> 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?
I'll haphazard a guess that it's because CURSOR now does all the things that
TVRDC used to do, including taking the optional WAIT parameter. CURSOR
certainly is documented. Back in pre-version 2 days, one used TVRDC for device
coordinates and CURSOR for data coordinates, but now CURSOR can work with both
data and device coordinates, as well as normalized coordinates, by using it
with the right keyword. I wouldn't be surprised if these days TVRDC is just a
synonym for CURSOR.
By the way, this is what I have for the possible values of the optional WAIT
parameter:
Value Corresponding Keyword Action
------------------------------------------------
0 NOWAIT Return immediately
1 WAIT Return if button is down
2 CHANGE Return if a button is
pressed, released, or the
pointer is moved.
3 DOWN Return on button down
4 UP Return on button up
With the default value being 1.
Bill Thompson
|
|
|
|
| Re: undocumented IDL built-in TVRDC [message #2296 is a reply to message #2292] |
Thu, 09 June 1994 22:21 |
landsman
Messages: 93
Registered: August 1991
|
Member |
|
|
> 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,
TVRDC is a synonym for the (documented) CURSOR command. Its origin goes
back to 1980's Version 1 IDL when the typical image processing environment
was a television display monitor controlled by a Tektronics or VT100 terminal.
Version 1 IDL then had a CURSOR command for reading the cursor off of a plot
on the Tektronics screen, and a TVRDC command to read the cursor on the
television display. In a workstation environment each window can be used
for image display or plotting, and the distinction between CURSOR and TVRDC
became unnecessary. CURSOR was chosen as the command for newer versions
of IDL, however TVRDC remained available as an undocumentd synonym. You
will find that TVRDC works exactly as documented under CURSOR.
--Wayne Landsman landsman@stars.gsfc.nasa.gov
|
|
|
|
| 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
|
Member |
|
|
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 |
| work. Any opinions expressed herein must therefore be someone else's. |
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
