Re: [pygame] Rotate image around another point?

[altern <altern2@xxxxxxxxx>]

john is talking about the actual image surface data not just the sprite 
location. i guess you might need something like PIL library, but i would 
not really know how to do this.

John Eriksson(e)k dio:
> But that is not what I'm trying to do.I want to rotate the actual
> imagedata (like rotating an image using PohotSshop or GIMP). Not just
> the location where the image is drawn. 
>
> The pygame.transform.rotate(...) function does that but always rotates
> the imagedata about it's center.
>
> /John
>
> tor 2007-04-19 klockan 11:02 +0200 skrev Ulf EkstrÃm:
> > On 4/19/07, John Eriksson <john@xxxxxxxxxxxx> wrote:
> > > Well, no.
> > >
> > > I'm looking for a way to rotate the imagedata (like
> > > pygame.transform.rotate(...)) but your example rotates the image
> > > location. Right?
> > It is actually the same thing. Rotation around some arbitrary point
> > can be decomposed into a rotation around some other point followed by
> > a translation. Suppose you have a function R which rotates things
> > around the origin. To write a function Rp which rotates around the
> > point p (p and q are vectors), you do
> >
> > Rp(q) = R(q-p)+p
> >
> > Since R is a linear function you can do
> >
> > Rp(q) = R(q) + p - R(p)
> >
> > So rotating around p is the same as rotating around the origin and
> > then translating by p - R(p).
> >
> > Ulf