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Class: Sketchup::FrameChangeObserver Abstract

Relationships
Inherits: Object

Overview

This class is abstract.

Implement the methods described in this class to create a frame change observer. You can not sub-class this class because it is not defined by the API.

This observer interface is implemented to react to changes in camera position (a frame) between one scene page and another. This observer’s callback method is called when the user manually makes a scene change, or the internal animation feature runs.

This abstract observer is any object that implements a callback method frameChange with 3 arguments: from_scene (the scene that you transition from), to_scene (the scene that you transition toward) and a percent_done between 0.0 and 1.0 (that indicates the percentage of transition between the two scenes.)

# Basic Class Definition:
class MyFrameChangeObserver
  def frameChange(from_scene, to_scene, percent_done)
   # Actual code here.
  end
end

The observer is attached using the Pages.add_frame_change_observer class method, which returns an integer id that can be stored and later used to detach the observer.

# Attach an observer to the global Pages object:
@id = Sketchup::Pages.add_frame_change_observer(MyFrameChangeObserver.new)

Later, detaching this observer is done by passing this id reference to the Pages.remove_frame_change_observer class method.

# Basic Observer Detachment:
Sketchup::Pages.remove_frame_change_observer(@id)

Examples:

Draws a progress bar on the status line.

class MyFrameChangeObserver
  def frameChange(from_scene, to_scene, percent_done)
    if percent_done == 0.0
      Sketchup.status_text= "% done:"
      if from_scene.nil? # PC bug!
        puts "Animating to page: '#{to_scene.name}'"
      else
        puts "From page '#{from_scene.name}' to '#{to_scene.name}'"
      end
    else
      Sketchup.status_text= "% done: #{'|'*(percent_done*100).to_i}"
      UI.messagebox("All Done!") if percent_done >= 1.0
    end
  end
end
@id = Sketchup::Pages.add_frame_change_observer(MyFrameChangeObserver.new)

Instance Method Summary

Instance Method Details

#frameChange(from_scene, to_scene, percent_done)

Note:

The from_scene argument into this callback does not appear to be populated on the PC. You can store a variable that keeps track of the to_scene and then use that on a subsequent Scene selection to determine the last Page that the user was on.

This callback method is called during a slide show or creation of an animation after the camera has been set up, but before the frame is displayed. It gives you a chance to perform your own actions during the animation. The arguments for frameChange method are the scene page that you transition from (from_scene), the scene page that you transition to (to_scene), and a percent_done between 0.0 and 1.0 that tell you the percentage of the transition between the two scene pages.

By watching for percent_done >= 1.0, you can activate Ruby code that executes as soon as the user’s camera has finished animating.

Examples:

class MyFrameChangeObserver
  def frameChange(from_scene, to_scene, percent_done)
    if percent_done == 0.0
      puts "Animating to scene '#{to_scene.name}':"
    else
      puts format("% 7.2f %",percent_done*100)
    end
  end
end
@id = Sketchup::Pages.add_frame_change_observer(MyFrameChangeObserver.new)

Parameters:

  • from_scene (Sketchup::Page, nil) —

    The previous scene page the view is transitioning from.

  • to_scene (Sketchup::Page) —

    The selected scene page the view is transitioning towards.

  • percent_done (Float) —

    The percentage of transition between the two scene pages.

Version:

  • SketchUp 6.0