VLR-SysVar-Reactor Help

[harrison-matt]

All,

 

I am looking for a way to create a reactor that changes a system variable back to specific variable when it is changed by a User or AutoCAD.

 

Specifically i am talking about MLEADERSCALE, you might have noticed that if you have several styles and you switch between them your Mleaderscale resets to 1 or the specific scale set in the style. I set dimscale and mleaderscale the same and when that change happens mleaderscale ends up changing forcing me to reset the mleaderscale after each time the style is changed.

 

I want to see the feasibility of using VLR-SysVar-Reactor and :VLR-sysVarWillChange and :VLR-sysVarChanged. I having trouble understanding the right code involved with these reactions. My furthest experience with VLR is just VLR-Command-Reactor's.

 

 

objective:

When Mleaderscale changes, it is reset to the current value of dimscale.

 

Any help or nudge would be greatly appreciated,

 

Matt

[BlackBox]

My two cents...

 

*IF* your intended goal is to change the value of a sysvar (assuming you set it correctly at open), then I would suggest going with the :vlr-sysVarChanged callback. If you're familiar with the syntax of vlr-command-reactor, then you should have no problems with the callback list items required for :vlr-sysVarChanged.

 

Put some code together, and test it. If you're still having trouble, or want to try something unique, post the code and let us know.

 

Hope this helps!

[lpseifert]

my version doesn't have the sysvar Mleaderscale so this is completely untested

(vl-load-com)
(defun mlsreact ()
 (if (not mls_react)
   (setq  mls_react (vlr-sysvar-reactor nil '((:vlr-sysVarChanged . mls2ds)))) 
 ) 
) 
(mlsreact)

(defun mls2ds    (event parameter)
 (if (eq (car parameter) "MLEADERSCALE")
   (setvar "mleaderscale" (getvar "dimscale")) 
     )
 )

[BlackBox]

As a wise man once said...

 

So much for teaching.

 

 

lol

[harrison-matt]

I tested this and the program resulted in an error crashing my autocad when the event is provoked.

 

my version doesn't have the sysvar Mleaderscale so this is completely untested

(vl-load-com)
(defun mlsreact ()
(if (not mls_react)
(setq mls_react (vlr-sysvar-reactor nil '((:vlr-sysVarChanged . mls2ds)))) 
) 
) 
(mlsreact)

(defun mls2ds (event parameter)
(if (eq (car parameter) "MLEADERSCALE")
(setvar "mleaderscale" (getvar "dimscale")) 
)
)

[lpseifert]

well I'll be dipped in sh**... hoped you learned something

[harrison-matt]

 

Me too, I am working on my program now, if i get anywhere or have any questions stick around.

[BlackBox]

well I'll be dipped in sh**... hoped you learned something

 

Me too, I am working on my program now, if i get anywhere or have any questions stick around.

 

 

Stay tuned.... same 'Bat-Channel', same 'Bat-Time'...

[alanjt]

You are creating your own infinite loop by having a reactor that activates each time the MLEADERSCALE is changed and setting it to something else, thus activating the reactor within the reactor.

 

Try something like this:

 

(defun mls2ds (event parameter)
 (if (and (eq (car parameter) "MLEADERSCALE")
          (/= (getvar "MLEADERSCALE") (getvar "dimscale"))
     )
   (setvar "mleaderscale" (getvar "dimscale"))
 )
)

This way it will fire the second time around, but it will notice that the MLEADERSCALE and the DIMSCALE are equal and will not continue.

[harrison-matt]

Thanks, now i get it!

[Lee Mac]

my version doesn't have the sysvar Mleaderscale so this is completely untested

(vl-load-com)
(defun mlsreact ()
 (if (not mls_react)
   (setq  mls_react (vlr-sysvar-reactor nil '((:vlr-sysVarChanged . mls2ds)))) 
 ) 
) 
(mlsreact)

(defun mls2ds    (event parameter)
 (if (eq (car parameter) "MLEADERSCALE")
   (setvar "mleaderscale" (getvar "dimscale")) 
     )
 )

 

Be careful of recursive looping Larry...

 

The reactor will react to the callback etc...

 

EDIT: Alan got there first - shoulda read the thread first...

[lpseifert]

Ya learn something new everyday... thanks to both

I guess I should have tested it with different sysvars. I might have found the problem prior to posting... oh well

[alanjt]

Ya learn something new everyday... thanks to both

I guess I should have tested it with different sysvars. I might have found the problem prior to posting... oh well

Long ago, I had to crash AutoCAD three times before I realized what the problem was.

[Lee Mac]

I've inadvertently done it too, don't worry

 

Usually happens with Object Reactors.. :S