| Re: ENVI menus, programmatically. [message #38541] |
Tue, 16 March 2004 14:25  |
Robert Moss
Messages: 74
Registered: February 1996
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Member |
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Peter Mason wrote:
> Robert Moss wrote:
>
>> Does anyone here know the trick to programmatically adding menu items
>> to ENVI? Yes, I have "googled" on this topic, and found one instance
>> that looked promising, but it doesn't really answer the question.
>> Clearly there is a way to do it... and it appears to involve creating
>> a procedure that has one parameter which is a data structure that
>> defines the menu structure. What happens inside this routine, or what
>> undocumented programs it may call, or what undocumented program call
>> it, is non-obvious. Any takers?
>>
>> Robert Moss, PhD
>> EOIR Technologies Inc.
>> robert.moss@nvl.DONOTSPAMTHEarmy.mil
>
>
> I wish that RSI would get on with it and document this interface as it is
> very useful. IMHO, they under-estimate the nuisance factor involved in the
> traditional route of editing the menu file. Even if you give
> copy-and-paste instructions to your users, it's _still_ a nuisance as they
> have to find the envi.men file, overcome the geek factor, and so on. Most
> ENVI users can't be having with this sort of run-around. (Other sorts,
> sure, but not this one :-))
> Whereas.
> I sort-of found out how this interface works a good few years ago and use it
> routinely. *It has been stable for a number of ENVI versions.* In the
> interests of motivating some genuine documentation, here's what I know:
>
> The system only kicks in if your file (.PRO or .SAV) is in ENVI's SAVE_ADD
> subdirectory.
>
> The action is in a special procedure that you write. This procedure is
> named after the .PRO or .SAV file that it's in: filename_define_buttons.
> For example, if the host file was called QWERTY.PRO or QWERTY.SAV then you
> would name your procedure: QWERTY_DEFINE_BUTTONS
>
> The procedure has one positional parameter. Call it B. So:
> pro qwerty_define_buttons, B
> I think that stuff can come in via B sometimes but have never worked out how
> to deal with that. What I know is that you can define B from scratch with
> just your own menu additions and - if you do it right - these additions will
> find their way into the ENVI menu.
>
> B is an array of structures, one element per item (node or leaf) of your
> menu additions. The structure definition is un-named, I think, and it
> looks like this:
> { parent:"", sibling:"", name:"", uvalue:"", event_handler:"",
> separator:0, display:0 }
> Straight away, you can see that it's a lot like an entry in the envi.men
> file.
> Anyway, for a given element in this structure array:
> Set PARENT to the name of an existing node under which to add this entry, or
> set it to an empty string to add this entry as a top-level item in the ENVI
> menu.
> Set SIBLING to the name of an existing node/leaf if you want this entry to
> appear just after it, or set it to an empty string to make this entry "go at
> the end".
> Set NAME to what you would like to call this node/leaf in the ENVI menu.
> Leave the other members empty/zero if this entry is a node. If it is a
> leaf (a module invocation) then continue...
> Set UVALUE to anything you like. (I don't use this item myself and don't
> know what it's for.)
> Set EVENT_HANDLER to the name of your module's top-level procedure (the same
> one that you would have specified in envi.men)
> I think that SEPARATOR gives you one of those menu partition things. I
> haven't used it.
> I think that DISPLAY, if set non-zero, might add your item to the display
> menu rather than the main menu. I haven't used it - I've always left it
> zero to add to the main menu.
>
> That's about it. You simply set up a structure array and return it.
> When ENVI starts, it goes looking in SAVE_ADD, restoring or compiling
> modules that it finds there. For each module, it'll look for a
> ..._DEFINE_BUTTONS procedure and it'll run it if found.
> What I don't know is how to get some interaction going if you have more than
> one module that's trying to add menus. i.e., If they share a common root
> node but it's a node that must be created, which one should have the
> honours? The trouble is that ENVI appears to discover files (in SAVE_ADD)
> according to some lower-level file-system thing rather than alphabetically,
> so you can't count on a discovery order. (I just try to avoid this
> situation by combining related modules into one .SAV file and having one
> DEFINE_BUTTONS procedure for the lot.)
>
> HTH
> Peter Mason
>
>
Thanks, Peter. You've made my life a little easier.
R
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