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Re: more log-scaled images [message #64292 is a reply to message #64286]

Tue, 16 December 2008 10:23

ben.bighair
Messages: 221
Registered: April 2007

Senior Member

On Dec 16, 11:42 am, "ben.bighair" <ben.bigh...@gmail.com> wrote:
> 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!

Hi,

Here is what I came up with: http://www.tidewater.net/~pemaquid/hbb_logimage.pro

To run an example...

IDL> .compile hbb_logimage
IDL> test_logimage

Cheers,
Ben

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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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