| IDLgrModel::Scale [message #20751] |
Thu, 20 July 2000 00:00  |
Mark Guagenti
Messages: 14
Registered: May 2000
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Junior Member |
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Hello,
I can't seem to figure out how the IDLgrModel::Scale method works. When I
scale a model that only contains a 2D image by doing the following:
oModel->Scale, 1.2, 1.2, 1
what would the equivalent of doing it with the congrid function? Wouldn't
it be:
imgData = Congrid(imgData, imgsizeX*1.2, imgsizeY*1.2
I guess I really don't understand how the scale method works. Any
enlightenment would be very appreciated.
Thanks,
Mark
-- Mark
Grace and peace to you from God our Father and the Lord Jesus Christ.
1 Cor. 1:3
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| Re: IDLgrModel::Scale [message #20785 is a reply to message #20751] |
Wed, 26 July 2000 00:00  |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Mark Guagenti (guagenti@foodsci.purdue.edu) writes:
> I guess the best way to describe my problem is that I need to be able to scale
> the image data itself, but I also need to scale the other graphic atoms that are
> in a model object. So that's why I was wondering how the IDLgrModel::Scale
> method works because I thought the best approach would to be scale all the atoms
> in the model with the IDLgrModel::Scale and then scale the image data with
> congrid. Where I run into a problem is that if I do oModel->Scale, 1.2, 1.2, 1
> I can't go and do Congrid(imgData, imgsizeX*1.2, imgsizeY*1.2) on the image data
> and get the same proportions. Does any one have an idea that might help?
I think you might be confusing the *visualization* of the data
with the data itself. Congrid, of course, will change the
actual dimensions of the image itself. Scale will effect
how the image (independent of its actual size) will be
viewed in the arbitrary coordinate system established
by the viewplane rectangle.
Although we often think of resizing the image when we
display it in direct graphics, this is completely
unnecessary in object graphics. In the latter system
all the details are done for us simply by the way
we place the image into the viewplane rectangle (and
by the way the viewplane rectangle is mapped into the
destination object).
Here is another case where it is best to forget everything
you ever learned about direct graphics if you are going
to successfully work with object graphics. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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| Re: IDLgrModel::Scale [message #20800 is a reply to message #20751] |
Tue, 25 July 2000 00:00 |
Mark Guagenti
Messages: 14
Registered: May 2000
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Junior Member |
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Hello All,
I guess the best way to describe my problem is that I need to be able to scale
the image data itself, but I also need to scale the other graphic atoms that are
in a model object. So that's why I was wondering how the IDLgrModel::Scale
method works because I thought the best approach would to be scale all the atoms
in the model with the IDLgrModel::Scale and then scale the image data with
congrid. Where I run into a problem is that if I do oModel->Scale, 1.2, 1.2, 1
I can't go and do Congrid(imgData, imgsizeX*1.2, imgsizeY*1.2) on the image data
and get the same proportions. Does any one have an idea that might help?
Thanks in advance,
Mark
Rick Towler wrote:
> Hi Mark,
>
> There will undoubtedly be a far better answer to your post but I might
> be able to get you thinking.
>
>> I can't seem to figure out how the IDLgrModel::Scale method works. When I
>> scale a model that only contains a 2D image by doing the following:
>>
>> oModel->Scale, 1.2, 1.2, 1
>
> You seem to be using it correctly. :)
>
> The difference is that in object graphics your scaling doesn't actually
> change the objects data. Your second approach (using congrid)operates
> on the image data itself and "scaling" the image smaller will result in
> lost data.
>
> -Rick
>
> Mark Guagenti wrote:
>>
>> Hello,
>> I can't seem to figure out how the IDLgrModel::Scale method works. When I
>> scale a model that only contains a 2D image by doing the following:
>>
>> oModel->Scale, 1.2, 1.2, 1
>>
>> what would the equivalent of doing it with the congrid function? Wouldn't
>> it be:
>>
>> imgData = Congrid(imgData, imgsizeX*1.2, imgsizeY*1.2
>>
>> I guess I really don't understand how the scale method works. Any
>> enlightenment would be very appreciated.
>>
>> Thanks,
>> Mark
>>
>> -- Mark
>>
>> Grace and peace to you from God our Father and the Lord Jesus Christ.
>> 1 Cor. 1:3
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| Re: IDLgrModel::Scale [message #20825 is a reply to message #20751] |
Mon, 24 July 2000 00:00 |
Rick Towler
Messages: 821
Registered: August 1998
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Senior Member |
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Hi Mark,
There will undoubtedly be a far better answer to your post but I might
be able to get you thinking.
> I can't seem to figure out how the IDLgrModel::Scale method works. When I
> scale a model that only contains a 2D image by doing the following:
>
> oModel->Scale, 1.2, 1.2, 1
You seem to be using it correctly. :)
The difference is that in object graphics your scaling doesn't actually
change the objects data. Your second approach (using congrid)operates
on the image data itself and "scaling" the image smaller will result in
lost data.
-Rick
Mark Guagenti wrote:
>
> Hello,
> I can't seem to figure out how the IDLgrModel::Scale method works. When I
> scale a model that only contains a 2D image by doing the following:
>
> oModel->Scale, 1.2, 1.2, 1
>
> what would the equivalent of doing it with the congrid function? Wouldn't
> it be:
>
> imgData = Congrid(imgData, imgsizeX*1.2, imgsizeY*1.2
>
> I guess I really don't understand how the scale method works. Any
> enlightenment would be very appreciated.
>
> Thanks,
> Mark
>
> -- Mark
>
> Grace and peace to you from God our Father and the Lord Jesus Christ.
> 1 Cor. 1:3
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