Re: Rotate NSString... I give up :( [SOLVED]
Re: Rotate NSString... I give up :( [SOLVED]
- Subject: Re: Rotate NSString... I give up :( [SOLVED]
- From: "Kyle Sluder" <email@hidden>
- Date: Wed, 6 Aug 2008 16:55:32 -0400
On Wed, Aug 6, 2008 at 4:37 PM, Vitaly Ovchinnikov
<email@hidden> wrote:
> Yes, he right. I've just tested it and it works fine.
> I though that -translateXBy:yBy: will move my object, but it moved
> pivot point... This is hard, especially with revesed OY axis ;)
Well, it all happens in one transformation matrix. If I recall matrix
math correctly (probably not), rotation is a linear transformation,
but translation isn't, so in order to get rotation to work right the
pivot point must be the origin. Since you want to rotate the object
around its center, you need to translate it twice. This is all
chained together in one transformation matrix, so when the
multiplication's done the net result is one matrix that does all three
operations.
Anyone, please feel free to correct me, I would very much appreciate
any clarification. :D
--Kyle Sluder
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