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Re: more log-scaled images [message #64299 is a reply to message #64293]

Tue, 16 December 2008 08:42

ben.bighair
Messages: 221
Registered: April 2007

Senior Member

On Dec 16, 4:18 am, Wox <s...@nomail.com> wrote:
> On Mon, 15 Dec 2008 19:00:55 -0800 (PST), "ben.bighair"
>
> <ben.bigh...@gmail.com> wrote:
>> I have been refreshing my memory on how to show an image with one (or
>> both) dimensions log-scaled.
>
> Have a look at this:http://hea-www.harvard.edu/~pgrigis/idl_stuff/pg_plotim age.pro

Hi,

Thanks. Yes, I was trying to model my routine on that one. My goal
is to exploit IDL's object graphics capability to work with images of
any interleaving (I'm not sure that is a real word, but you know what
I mean.) In the end, I want a generic routine for smushing the image
instead always plotting which I can do later if needed.

I discovered the issue. Surfaces are defined by the node locations
and texture mapping occurs from the node to the next node to the right
and up. Since my surface ran 1 - n, the last node had nowhere to draw
the texture map to, so the texture drawing rightly truncated at the
last node to at the right and at the top. I think this is the similar
to the issues we all encounter when using the POLYFILLV routine that
defines a pixel location as the lower left.

The trick is to make the surface onto which the image is mapped one
node bigger than the image dimensions. For example, if the image
dimensions are [100,200] then make the surface [101, 201] - and viola!

I'll clean up what I have and post it when I can.

Thanks again!
Ben

P.S. Whew!

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[Message index]

		Re: more log-scaled images By: ben.bighair on Wed, 17 December 2008 10:33
		Re: more log-scaled images By: Wout De Nolf on Wed, 17 December 2008 02:31
		Re: more log-scaled images By: ben.bighair on Tue, 16 December 2008 10:23
		Re: more log-scaled images By: ben.bighair on Tue, 16 December 2008 10:23
		Re: more log-scaled images By: ben.bighair on Tue, 16 December 2008 08:42
		Re: more log-scaled images By: ben.bighair on Tue, 16 December 2008 08:42
		Re: more log-scaled images By: Wout De Nolf on Tue, 16 December 2008 01:18
		Re: more log-scaled images By: Brian Larsen on Thu, 18 December 2008 07:39

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