| Re: destroying graphics objects [message #19544] |
Wed, 05 April 2000 00:00  |
Struan Gray
Messages: 178
Registered: December 1995
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Senior Member |
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Brad Gom, b_gom@hotmail.com writes:
> I know this is better form, but it would simplify
> things for me if I just had a conainer for just
> the plot objects and nothing else, and delete the
> container when necessary without worrying about
> what else is in the model.
There are always several ways of doing things, but if the combined
plot is not a useful object in its own right (i.e. if it doesn't
represent some kind of synthesis from the data) I would prefer to keep
control of the individual plots outside the pure display routines.
The simplest way to do this is to put all the individual plots
into an IDLgrModel, which as someone said, is subclassed from the
container object. This will let you adjust the scaling position and
orientation of all the plots at once, which is useful when changing
the display window or when printing.
The trick is to add this model to a second model using the /alias
keyword. Then you can pass the second model to the graphics
hierarchy. Everything will plot correctly but when the graphics
heirarchy is destroyed only the second model gets auto-destroyed,
leaving the first model and all your plots intact in memory.
A final advantage is that you can add models as aliases to any
number of other models, which allows you to have multiple views of the
same data on screen. If, say, you want to adjust one of the plots,
you can display it in a seperate graphics window for editing, and see
the updates live in both the single plot and the multi-plot window.
Eventually you end up with a proliferation of views, scenes and
printer objects all displaying one of your plots in various ways.
Despite the complexity, you know exactly who 'owns' the plot and when
it will and won't be auto-destroyed.
Struan
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