| Re: Transformation of Objects and Models [message #61976] |
Tue, 19 August 2008 05:16  |
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Erik[1]
Messages: 23
Registered: December 2006
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Junior Member |
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On 18 aug, 21:42, Rick Towler <rick.tow...@nomail.noaa.gov> wrote:
> ben.bighair wrote:
>> On Aug 18, 6:37 am, Erik wrote:
>>> Hi all,
>
>>> I'm working on a piece of code to make the handling of IDLgr objects a
>>> lot easier (IDL 6.3). The goal is to easily select some visual objects
>>> like ROI's, Lines and Text and move / resize or rotate them in the
>>> drawwidget.
>
>>> I used the translate/rotate/scale functions of the IDLgrROI / IDLanROI
>>> object a lot and it does exactly what it's supposed to do. But
>>> unfortunately the other IDLgr objects (like; IDLgrPolyLine, IDLgrText)
>>> does not have the transformation functions that the ROI object has :-
>>> ( . For example, to move a polyline, I cannot use the code oLine->Translate, tx, ty. Instead I must retrieve and alter the DATA
>
>>> property. To move a IDLgrText object, this must be done with the
>>> LOCATION property... and so forth.
>
>>> To make things easier I expected the IDLgrModel object to supply the
>>> solution for me, because the model has the same transformation
>>> functions as a ROI. At first glance, it seems to work. When I add a
>>> line to a model and give a translate command, the line get moved as
>>> expected. Same story for IDLgrText and IDLgrROI objects, so I suppose
>>> this works for any object that can be added to a model.
>
>>> My complaint however, is that the actual DATA of the IDLgr Objects
>>> stays the same! When I move a line to the right on my window, I also
>>> want the Object's X-data to be changed! It seems like the
>>> transformation of the Model does not do this :-( .
>
>>> I can understand if the Model is not meant to change this data, but
>>> why doesn't have all IDLgr objects the same commands for
>>> transformation?
>
> Because you are supposed to stick those objects in models and not
> transform them by altering their underlying data. :) If you mean to
> drag around your graphic objects by changing their underlying data
> values I foresee headaches and unreasonably slow and complicated code in
> your future.
>
> The usual approach would be to stick every movable object in its own
> model. Transform the model and forget about the object's underlying
> data. If for some reason after dragging your object just so, you need
> to extract the transformed vertices you can get the model's
> transformation and apply that to the verts yourself.
>
> -Rick
Thanks for your reply's. The reason why I wanted to alter the
underlying data, is because the property's of the objects will be used
for the rest of the program. For example, the number of counts in a
ROI will be different if the ROI is placed elsewhere on the widget.
Same goes for lines, which can be used to determine a start of an
analysis over a linogram. Guess I'll need to extract the model
tranformation then!
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