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Re: IDLgrImage image plot problem [message #50297] Tue, 26 September 2006 14:11 Go to next message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
yy writes:

> I want to plot a 2D data set by using object graphics.
> And I want it to be colored. If I use direct graphics plot,
> it can be done as the following:
> WINDOW, 0, XSIZE=300, YSIZE=300
> LOADCT,13
> IMAGE_AX, 2ddata
>
> However, when I try to use IDLgrImage, nothing appears
> on screen. I don't know if it's because I didn't position the
> image correctly. But if it is, I still don't know how to find the
> image. Below is what I did:
> oWindow = OBJ_NEW('IDLgrWindow', DIMENSIONS=[300,300])
> oView = OBJ_NEW('IDLgrView')
> oModel = OBJ_NEW('IDLgrModel')
>
> ; Load color table 13
> oPalette = OBJ_NEW('IDLgrPalette')
> oPalette -> LoadCT, 13
> oImage = OBJ_NEW('IDLgrImage', 2ddata, PALETTE = oPalette)
>
> oModel -> Add, oImage
> oView -> Add, oModel
> oWindow -> Draw, oView

Well, I think what you put in the window is the lower-left
pixel of your image. Don't worry, in my experience about
85% of the people who start using object graphics in IDL
do this. I certainly did. :-)

You are going to have to decide what kind of coordinate
system you are going to use in your view object. It
might make a LOT more sense to use a coordinate system
more in line with your image dimensions that with the
default coordinate system that will show a single pixel.
Check your viewplance rectangle. And you might have a look
at ximage.pro in the Coyote directory for an alternate way
to get to the same place:

http://www.dfanning.com/programs/ximage.pro

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Re: IDLgrImage image plot problem [message #50390 is a reply to message #50297] Tue, 26 September 2006 16:40 Go to previous message
yy is currently offline  yy
Messages: 14
Registered: September 2006
Junior Member
Thanks for your reply. I'm wondering if there is some other problem
since when I try to run the CenteringAnImage.pro code provided in IDL
help. I still can't see anything in the window. I don't know what is
going on.

Jingyi

David Fanning wrote:
> yy writes:
>
>> I want to plot a 2D data set by using object graphics.
>> And I want it to be colored. If I use direct graphics plot,
>> it can be done as the following:
>> WINDOW, 0, XSIZE=300, YSIZE=300
>> LOADCT,13
>> IMAGE_AX, 2ddata
>>
>> However, when I try to use IDLgrImage, nothing appears
>> on screen. I don't know if it's because I didn't position the
>> image correctly. But if it is, I still don't know how to find the
>> image. Below is what I did:
>> oWindow = OBJ_NEW('IDLgrWindow', DIMENSIONS=[300,300])
>> oView = OBJ_NEW('IDLgrView')
>> oModel = OBJ_NEW('IDLgrModel')
>>
>> ; Load color table 13
>> oPalette = OBJ_NEW('IDLgrPalette')
>> oPalette -> LoadCT, 13
>> oImage = OBJ_NEW('IDLgrImage', 2ddata, PALETTE = oPalette)
>>
>> oModel -> Add, oImage
>> oView -> Add, oModel
>> oWindow -> Draw, oView
>
> Well, I think what you put in the window is the lower-left
> pixel of your image. Don't worry, in my experience about
> 85% of the people who start using object graphics in IDL
> do this. I certainly did. :-)
>
> You are going to have to decide what kind of coordinate
> system you are going to use in your view object. It
> might make a LOT more sense to use a coordinate system
> more in line with your image dimensions that with the
> default coordinate system that will show a single pixel.
> Check your viewplance rectangle. And you might have a look
> at ximage.pro in the Coyote directory for an alternate way
> to get to the same place:
>
> http://www.dfanning.com/programs/ximage.pro
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
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