Re: How to animate an object in a circle, but preserve it's orientation
Re: How to animate an object in a circle, but preserve it's orientation
- Subject: Re: How to animate an object in a circle, but preserve it's orientation
- From: Miles <email@hidden>
- Date: Fri, 5 Jun 2009 09:13:35 -0700
Awesome -- I'll give it a go. That makes total sense. Thanks so much!
On Thu, Jun 4, 2009 at 9:04 PM, Graham Cox <email@hidden> wrote:
>
> On 05/06/2009, at 1:48 PM, Miles wrote:
>
> Thanks for the quick response!
>>
>> I've mostly been reading trying to see what would work. I did mess with
>> changing the anchorPoint to get the initial animation route, but that didn't
>> seem to suffice.
>>
>> The object I'm animating is a simple UIView containing an image.
>>
>> I thought about the timer approach like you mention, the reason I shy'd
>> away from it was that it needs to stay in sync with another animating object
>> (in my ferris wheel example this would be the wheel itself.)
>> But now that I think of it I might be able to use the timer to animate
>> that as well so they do stay in sync.
>>
>> Does that seem like the best and/or easiest approach?
>>
>
>
>
> Well, I'd say it can be made to work, but I personally wouldn't do it this
> way.
>
> It's still a bit vague, but I'm visualising a Ferris Wheel with a number of
> (one or more) attached basket objects. To model this, I would define the
> angle and radius as properties of the wheel, and the position of the basket
> as a property in terms of its position relative to the wheel (a fixed angle,
> say). The basket objects could be owned by the wheel, which makes good sense
> to me.
>
> To animate the rotation of the wheel, simply increment the angle of the
> wheel. This in turn directly or indirectly updates the positions of its
> attached baskets. The whole thing is then redrawn in the new position. The
> absolute location of a basket can be simply calculated as needed when the
> basket is drawn, based on the wheel's angle, radius and relative position of
> the basket on the wheel.
>
> Any time I hear people talking about "keeping things in sync" alarm bells
> ring. Instead, make one property a derivative or dependency of the other,
> then there is nothing to 'sync', it's always in sync.
>
> In terms of visualising the wheel/basket model in a view, I'd just use a
> custom view and drawn the entire content. The wheel object could draw
> itself, which in turn calls on each of its basket objects to draw
> themselves, and so on. Trying to make each basket a separate view will be
> inefficient and more complicated than this.
>
> --Graham
>
>
>
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