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Re: How to draw a line on an image? [message #5665 is a reply to message #5663]

Mon, 29 January 1996 00:00

offenbrg
Messages: 31
Registered: August 1993

Member

yoshida@fermi.bsd.uchicago.edu (Hiro Yoshida) writes:

> Hello IDL experts,

> Is there a handy way to draw lines on an image in IDL?

> I would like to draw some simple graphics such as lines, boxes, and circles
> on an image. (I am not talking about modifying image itself by putting
> white pixels to draw these figures.) I believe that IDL has some commands
> for this type of "overlay" task. Unfortunately, however, I cannot find one
> so far. Any suggestions are welcome.

I believe that the routine you want is "plots" (not "Plot"), which
allows you to draw graphics on a TV window (such as lines, circles, etc).
Also tvcircle and tvbox.

Now, this does change the image as stored in the window. The array stored
in memory will not be changed by this. There isn't really any way to
"overlay" in video memory without altering the contents of the window.

What you *could* do is copy the image into a pixmap window, so you can
recover it unchanged after you've finished with the graphics. The only
other trick I can think of involves using a 24-bit display...

Joel

--
"...And I am unanimous in this" - Mrs. Slocumbe
------------------------------------------------------------ ----------
| Joel D Offenberg | offenbrg@fondue.gsfc.nasa.gov |
| Hughes STX, NASA/GSFC/LASP | I get paid to stare into space. |

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[Message index]

		Re: How to draw a line on an image? By: David Foster on Wed, 31 January 1996 00:00
		Re: How to draw a line on an image? By: kennealy on Tue, 30 January 1996 00:00
		Re: How to draw a line on an image? By: Hermann Mannstein on Mon, 29 January 1996 00:00
		Re: How to draw a line on an image? By: offenbrg on Mon, 29 January 1996 00:00
		Re: How to draw a line on an image? By: Ian E. Sprod on Mon, 29 January 1996 00:00

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