[PD] animation api

[Jonathan Wilkes]

Having an animation method allows GUI-side optimizations that aren't 
possible when the animation is smeared across the socket/parser/eval'er.
Determinism: GUI rendering isn't deterministic, at least not in the way Pd's 
scheduler is.  For example, how could the GUI (tcl/tk or otherwise) even 
know that it missed a deadline?

I guess the simple API I'm toying with is "stretching the accordion" so to 
speak, and potentially showing the cracks more explicitly with a longer 
running animation than can currently be seen in Pd's GUI.  But that can be 
remedied, either by recursively halving a single animation into smaller ones, 
or just giving up and using [line].

The greater benefit is that more elegant types of visual feedback become 
possible without being discarded out of hand due to their potential for 
audio interruption.
-Jonathan

    On Monday, January 4, 2016 5:20 PM, Ivica Ico Bukvic <ico at vt.edu> wrote:
 

  On 1/3/2016 3:24 PM, Jonathan Wilkes wrote:
 
     It's actually way more simplistic than that-- just an "animate" method that 
  wraps around whatever attribute is available to the drawing command.  All 
  I'll have is a ramp time, an optional delay time, and an optional easing curve. 
  That will make it a bit like a [vline~] for GUI side animation. 
  I'm using the web animations API because it makes things very simple, even 
  to do complex things like animating path data. 
  The idea is that this would open up some modest visualization opportunities 
  that are otherwise too cpu intensive.  For example, if you're animating 
  using [line] the socket messages can quickly get in the way of the audio.
      
 
 Will you at some point drown the CPU? Sure, but that is no different than a million of other ways of doing the same. OTOH, implementing the animation this way helps you ensure that your animation remains in sync with the audio, which to me seems much better gain than a potential CPU/socket overhead may be a shortcoming.
 
 There could be some very cool ways of filtering gui messages, as well (short of getting rid of the socket-based communication in favor of a shared memory/multithreaded design). For instance, your animation object could be given the screen refresh rate and therefore it would not send out a message via a socket unless a desired frame-worth of time has transpired since the last message was sent. This would do wonders not just in terms of animation, but also the overall gui responsiveness, if implemented system-wide.
 
 Best,
 
 Ico
 
 
     
  -Jonathan
  
  
  
  
   
 
        
 
    On Sunday, January 3, 2016 1:08 PM, Ivica Ico Bukvic <ico at vt.edu> wrote:
  
 
    I think it may make sense in addition to having a one-shot-independent animations that have no guarantee of staying in sync with the audio (e.g. these could be useful for mouse-over button animations) that your animation object can also receive a decimal value between its originator and destination, allowing for each keyframe to be a whole number. So, 0-1 would interpolate between  the starting state and first keyframe, 1-2 between first and second keyframes, etc., and thus allow pd to use its timing mechanism to project changes in animation state via a line object, a counter or something similar. IIRC most (all?) HTML5-based  animations can be triggered as independent events or can be given a specific percentage value. The one-shot object could interact with independent events, while the proposed object could interact with the latter.
 
 That said, not knowing how you have imagined your animation object, it may be tricky to implement this as it would require object to keep track of all the keyframed events (assuming there are more than one). If you are thinking of having the  animation object track only one single animation (e.g. something progressing from 30% to 90%), the same could still prove useful except in this case you would only allow for values between 0 and 1.
 
  On 1/2/2016 1:12 PM, Jonathan Wilkes via Pd-list wrote:
  
  Hi list, I'm playing with adding a simple animation api to data structure drawing commands. 
  The parameters will be sent to the GUI, and the GUI will take care of the ramp, delay, etc. 
  I'm thinking of just making it a simple "set it and forget it" api.  That is, you send a message 
  with your ramp and delay times to the GUI, and you just blindly trust that the GUI will make 
  things happen in the right amount of time.  The alternative I can think of is to have the GUI 
  call back when an animation is finished, but that would encourage mixing the two clocks 
  (i.e., GUI and Pd clock) in unpredictable 
  ways. 
  Does this simple approach seem like a reasonable design?  The biggest problem would be that 
  a long-running animation could skew.  But in that case you could probably amortize the cost of sending more messages over the longer time period.
  
  -Jonathan
   
  
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