Scaling of keyframes/keypoints

aplman · January 16, 2013

Hello Igor NS FRIENDS ... SUGGESTIONS RE ANIMATION IN PTE

This suggestion was put forward in February 2010. It received a very enthusiastic response from Peter (fh1805), but not a comment from anyone else. If I have not explained my thoughts well, then I should re-work the item. Trouble is, it will be even longer than now!

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I am now using PTE 7.5 (was 6.02 back then). I think PTE is a wonderful program, and in general the animation features are implemented brilliantly. However, I gather from some recent discussion on the forum (both then and now) that some users do not find those features as exciting as I do.

I have only one complaint, and that concerns the way keypoints are relocated when the duration of a slide is changed. Here are my suggestions as to how things might be enhanced.

Specification of Keypoint Location

I note that keypoint objects in a PTE file have their locations defined by the Origin= parameter and the Time= parameter. Origin can be SlideBegin, PrevEffectEnd, NextEffectBegin or SlideEnd (Let us call those the four “special points”). Time is a number of millseconds relative to the specified Origin.

For keypoints that do not lie at one of those special points, the PTE user interface appears always to generate a time relative to SlideBegin. However, I have successfully edited PTE files to have keypoint locations specified relative to the other special points, and both positive and negative time values appear to work. However, if I subsequently move the keypoint (in Objects and Animation), its Origin reverts to SlideBegin (with the Time value suitably adjusted).

The present behaviour has some unfortunate effects. For example:

(1) if a slide’s duration is reduced, and “Scale keypoints” is unchecked, keypoints that were within the main viewing time of the slide (between transitions) can end up in the next transition;

(2) if a slide’s duration is increased or reduced, and if “Scale keypoints” is checked, keypoints that were placed at PrevEffectEnd or NextEffectBegin are no longer located at those special points;

(3) keypoints can get out of sequence, when those at the special points remain there, while others move past them.

I suggest a change to the PTE program could free us users from these problems. It would be better if each keypoint had its Origin set to the nearest one of the four special keypoints, and its Time value as a positive or negative offset from its Origin. This should apply both to the initial creation of the keypoint, and to its new position after a move. This way, we would get the following benefits:

(1) keypoints that are placed at one of the four special points would remain there,

(2) keypoints that are supposed to be within a transition would remain within that transition,

(3) keypoints that are supposed to be between the transitions would remain there.

All these are true whether “Scale keypoints” is in effect or not.

Scale Keypoints

It remains useful to keep the option “Scale Keypoints”. Scaling should be applied within the range of adjacent special points, not across the whole range from SlideBegin to SlideEnd. In other words, scaling should apply to keypoints within a transition when the transition duration changes. Keypoints between PrevEffectEnd and NextEffectBegin should be scaled within that range only.

If the user wants to adjust the duration of a slide, by extending or reducing the main viewing time (between transitions), but wants to keep the timing of the animations near the start and near the end, then Scale Keypoints would be unchecked. If the aim is to adjust the duration of a slide and the animations within the main viewing time, then Scale Keypoints would be checked. In neither case is any animation within a transition affected.

On the other hand, if there is animation within a transition, then its keypoints should be adjusted when the transition duration is changed. This would have no effect on animation within the main view time.

Potential Problems

A reduction in slide duration, without keypoint scaling, could cause keypoints to “collide” or cross over in the centre. This should provoke a message to the user, with the option to cancel the change or drop the keypoints.

Removing a transition should cause any keypoints within the transition to be dropped.

Possible extensions

It might be worthwhile to allow a right-click option on keypoints to enable them to be “anchored” to any one of the four special points. Different colours could be used to give visual feedback.

It might be beneficial to have one more special point: Centre - Half way between PrevEffectEnd and NextEffectBegin.

Thank you, Igor, for giving this your consideration. If anyone else has read this far, I say THANK YOU!

APLman (Ken Travers) - Moss Vale NSW Australia

fh1805 · January 16, 2013

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Scaling of keyframes/keypoints

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