Animation Commands

This page defines the animation command syntax and expected behavior (this is related to ticket:9055, see also ticket:9404). The command syntax is implemented in these ​animation commands.

Note on Syntax Style

Greg's suggested using ​extended Backus-Naur form. It was used it to define a ​nucleotides command (see the ​source code comments too).

Proposed command syntax

Elaine's "corrected scheme" from ticket:9055.

"scene" is analogous to ​savepos + ​reset, "animate" is completely analogous to ​fly, except they all work on scenes instead of positions and frame arguments can be followed by comma and transition name (previously defined with "transition").

• ​http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/savepos.html
• ​http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/reset.html
• ​http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/fly.html

(1) scene definition

scene scene-name (save | reset [frames[,trans-name]])
scene list
~scene (scene-name | all)

Notes

• "scene-name" and "trans-name" are user-specified, see (2) for the latter. The "trans-name" is optional -- omitting it uses a "default" transition.
• default scene not necessary.
• save corresponds to scadd.
• reset corresponds to scshow.
• scsave to file omitted for now, could be third option "write pathname".
• alternative: expand existing reset command to restore scenes, then only need:

  scene scene-name
  scene list
  ~scene (scene-name | all)
  

Scooter's proposal

Scooter proposed two minor modifications (according to Elaine):

1. change

   scene scene-name (save | reset [frames[,trans-name]])
   

   to only

   scene scene-name (save | reset)
   

   thus disallowing gradual transitions using the "scene" command. Instead only the "animate" command would show gradual transitions.

2. Have a special scene name that always means the current scene. Then "animate" could be used with the syntax of Elaine's proposal (see below) to go from the current scene to any other.

Implementation note

r33799 provides revisions to 'scene' command:

scene <scene-name> save
scene <scene-name> reset
scene <scene-name> reset <intFrames>
scene list
~scene <scene-name>
~scene all

Notes:

• args to (scene | ~scene) are comprised of any non-whitespace characters, unless they are 'action' keywords (list | save | reset | all) or otherwise noted below. It is possible to save a scene called 'scene' using "scene scene save", or a scene called 'save' using "scene save save", but it is never possible to save a scene named 'list'.
• Unless the first arg to 'scene' is 'list', it must be a <scene-name> (there is no default) and the 'save' or 'reset' action is required (there is no default).
• For reset, it is an error to specify a <scene-name> that was not previously saved.
• The <intFrames> argument to reset is optional, the default is 1 frame; when it is given, it must be an integer (the value provided is cast using int()).
• The reset command effects a transition from the current display state to a saved <scene-name> state.
• When transition commands are defined and implemented, the scene command set might be augmented with a transition name:

  scene <scene-name> reset [<intFrames>[,<trans-name>]]
  

(2) transition definition

transition trans-name [color color-options] [visibility vis-options] \
                      [style style-options] [global global-options]
transition list
~transition (trans-name | all)

Notes

• Keywords could be different, I just wanted to convey purpose/scope ... many many possibilities, e.g.

  color ( linear [f1,f2] | sigmoid [f1,f2] | abrupt f )
  

  where f are % fractions of the transition from the preceding scene (0%) to the next scene (100%). A percentage is easier to type than values in the 0-1 range.
• Would we want to allow different behaviour for different models?

(3) animation between scenes

This may be analogous to the existing ​fly command:

fly [master-frames] pos1 \
    [[ frames1_2] pos2] \
    [[ frames2_3] pos3] \
    ... \
    [[ framesN-1_N] posN]

see ​http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/fly.html

That is, we define a new command called 'animate' with similar syntax:

animate [master-frames[,master-trans]] scene1 \
    [[ frames1_2[,trans1_2]] scene2] \
    [[ frames2_3[,trans2_3]] scene3] \
    ... \
    [[ framesN-1_N[,transN-1_N]] sceneN]

Notes

• scene*, trans* previously defined with scene and transition commands, respectively.
• alternative: expand existing fly command to do all this.

Concerns:

• Does this limit transitions (other than positions, which would be splined as in "fly") to depending on only the bracketing pair of scenes? Do we need fancier transitions that also depend on further preceding and following scenes?
• How does animation integrate with recording, 2dlabels, coordset, other commands with frame arguments (move,turn,rock,roll)? Simply as interleaved commands between "movie record" and "movie stop"? Could coordset or 2dlabels changes occur at the same time as other transitions?