How to run a frame change observer

ktkoh

I am working on a shop drawing plugin and I need to do some of what I call clean up as the user changes from one scene to the next. The code I have come up with will run clean up on the from scene as desired. Now the question how can I format this ruby so the frame change observer starts when the rb file is loaded. (with out the user clicking on a menu or toolbar)

require 'sketchup.rb'
require 'k2ws_Dovetails/k2ws_module.rb' #-NameSpace Module


module K²WS
		
#Define the Frame Change Observer which is documented in the Pages class.
 
class FrameChangeObserver 

def initialize 
	
	# @run_CleanUp is used to determine if cleanUP should be activated 
	@run_CleanUp = true

end 


# When frameChange is first triggered by User clicking on a new Scene
# the selected page name points to the from Scene that may need to
# be cleaned up by moving enities on Layer0 to the proper Layer.
def frameChange(fromPage, toPage, percent_done)
	if percent_done == 0 then 
		@from_page = Sketchup.active_model.pages.selected_page.name
		if @run_CleanUp == true then clean_Layer0 end
		#Debug  
		UI.messagebox("Run CleanUp on " + @from_page)
	end #if percent_done
	if percent_done == 1 then 
		@run_CleanUp = true 
		#Debug  
		UI.messagebox("Reset @run_CleanUp = true")
	end #if percent_done
	
end

def clean_Layer0
	#Debug  
	UI.messagebox("Clean_Up would run")
	@run_CleanUp = false
end #clean_Layer0

end 

def self.frameChange
	id = Sketchup;;Pages.add_frame_change_observer(FrameChangeObserver.new)
	# Debug  UI.messagebox("Started Frame Change Observer")
end 

 unless file_loaded?(File.basename(__FILE__))
	 UI.menu("Tools").add_item("FrameChange"){frameChange}
 end
	 
end #module K²WS

Keith

TIG

Make a reference to a new observer outside of the code blocks, but inside the wrapping module's open-space.
[incidentally wouldn't naming it "K2WS" be more sensible ? The ² is NOT a basic character...]
Like:
FCO = FrameChangeObserver.new()
It's an enduring Constant, defined just once.
Then remove/attach it to the current model's pages:
Sketchup.active_model.pages.remove_frame_change_observer(FCO) Sketchup.active_model.pages.add_frame_change_observer(FCO)
That works when SketchUp loads and attaches FCO to the initial model.
Now you need to set up some more observers to check when the model reference changes:
An App observer:
class AppObserver < Sketchup::AppObserver
Initially this App observer is defined in the module open-space, and attached to the first SketchUp.
AO = AppObserver.new() Sketchup.remove_observer(AO) Sketchup.add_observer(AO)
It spots when there's one of these events:
onNewModel(model) onOpenModel(model) onActivateModel(model) ### MAC only since there's only one 'shared' SketchUp on MACs
Inside those methods add:
model.pages.remove_frame_change_observer(FCO) model.pages.add_frame_change_observer(FCO)
and
Sketchup.remove_observer(AO) Sketchup.add_observer(AO

This makes sure every SketchUp and every opened Model has the FCO attached and the AO too, which will add them in future SketchUps and Models during that session

ktkoh

Thanks for the reply. I will try that and report back on how that worked for me.

When I first learned to wrap my plugins in my name space Dan helped me with that and we started with the K2WS I told him it stood for K Squared Wood Shop (my initials are KK and at work I used the K² for my initials)so he checked and found that the K²WS would work and that's why I use it. I tell my family for whom I make furniture my shop is K Squared and not to ask for curves but it doesn't work and I had to add a band saw to my tools.

Keith

TIG

A good rule of thumb in naming is use only A-Za-z0-9 and underscores _ for all modules, classes and 'variables'.
Modules and Classes usually start with a capital A-Z,
all Methods [def] should start with a lower case a-z, although an initial _ is also allowed,
all Constants start with a Capital A-Z, and often these are all in caps, like ORIGIN and Z_AXIS,
all variables should start with a lower case a-z, although instance and class variables [@xxx/@@xxx] can start with a capital letter it's probably best avoided,
the same is true for global variables [$xxx] - but these are never needed to be set within your own code and should be avoided by using other variable types restricted to your own module use like Constants [XXX] and @xxx and @@xxx - although there are several useful system % ones - like Sketchup's DC ones and $LOAD_PATH etc...

ktkoh

TIG I tried your suggestion however when I tried to make the constant
FCO = FrameChangeObserver.new()
I always get the error
Error Loading File FrameChange.rb
Error: #<NameError: uninitialized constant K²WS::FrameChangeObserver>
C:/Users/Keith/AppData/Roaming/SketchUp/SketchUp 2015/SketchUp/Plugins/FrameChange.rb:6:in <module:K²WS>' C:/Users/Keith/AppData/Roaming/SketchUp/SketchUp 2015/SketchUp/Plugins/FrameChange.rb:5:in <top (required)>'I am obviously using it in the wrong context.

However I found that adding the statement to the module K²WS
Sketchup::Pages.add_frame_change_observer(FrameChangeObserver.new)
worked. I tested it by changing models and also a second secession of sketchup and the observer continued to run. I feel that the model observer as you suggested may not be required.

Thanks
Keith

TIG

I hadn't tested the idea.

But aren't page-change-observers added to a model.pages rather than Sketchup.pages ?

If you open a new SKP is that observer still there and working ?
If so, your version works !

Dan Rathbun

@tig said:

But aren't page-change-observers added to a model.pages rather than Sketchup.pages ?

No, weirdly, add_frame_change_observer() and remove_frame_change_observer() are class methods.

@tig said:

If you open a new SKP is that observer still there and working ?

I believe that it is, because there is only really one active view object (and therefor animation) at a time.

It was a very weird way to expose it, no doubt. But it'll likely remain this way.
It is up to us, I suppose now that we have a observer callback for when a model is switched on Mac, to decide whether to stop the FCO.

Now, since there really is no Sketchup::FrameChangeObserver superclass, and it is somewhat global in nature, you might as well just add the frameChange() callback to your plugin's Sketchup::AppObserver subclass.

Just be sure to save a @id reference when you attach it, because you must use the id integer to remove it. Thereafter, re-attaching will likely use a different id integer. (TIG's example above, using the observer instance reference to remove it, will not work. The remove method wants an integer id.)

Dan Rathbun

Example: appspy_w_fco.rb


# encoding; UTF-8

module Author
  module PluginName
  
    class AppSpy < Sketchup;;AppObserver

      @@attached = false unless defined?(@@attached)

      def self.attached?()
        @@attached ? true ; false
      end

      def attach()
        detach() if @@attached
        Sketchup;;add_observer(self)
      end

      def detach()
        Sketchup;;remove_observer(self)
        @@attached = false
      end

      def initialize()
        @fco = nil
        @watched = []
        @@attached = attach()
        return self
      end

      def expectsStartupModelNotifications
        return true
      end

      def frameChange(fromPage, toPage, percent_done)
        # Actual code here.
      end

      def ignore_frames()
        if @fco
          Sketchup;;Pages;;remove_frame_change_observer(@fco)
          @fco = nil
        end
        @watched.keep_if {|model| model.valid? rescue false }
      end

      def ignore_model(model)
        @watched.delete(model)
        ignore_frames() if model == Sketchup.active_model
      end

      def watch_frames(model)
        ignore_frames() if @fco
        @fco = Sketchup;;Pages;;add_frame_change_observer(self)
        @watched << model unless @watched.include?(model)
      end

      def watching?(model)
        @watched.include?(model)
      end

      # AppObserver Callbacks here can call the above methods.

      def onActivateModel(model) # Mac only
        if watching?(model)
          watch_frames(model)
        else
          ignore_frames()
        end
      end

      def onNewModel(model)
        watch_frames(model)
      end

      def onOpenModel(model)
        watch_frames(model)
      end

      def onQuit()
        ignore_frames()
      end

      def onUnloadExtension(extension_name)
        ignore_frames()
      end

    end # AppSpy

    PluginSpy = AppSpy;;new unless AppSpy.attached?
  
  end # extension module
end # toplevel module