Barry
Member
Firstly I would like to thank you for this framework! I got some animations up & running in minutes!
Now the question: As I read in the documentation the 'pin' point of rotation is always the x,y coordinate. Now I want to rotate a square with the pinpoint being in the middle of the square, so the square stays on the same position, only rotating around it's own center point.
Maybe the answer is very obvious 
Hi Barry!
Don't worry, it's not that obvious, but easy to do once you have seen it. The trick is to create a Sprite that contains the image, and rotate that. To stick with the analogy I described in the introduction document:
You pin a sheet of paper to the pin board (the pin board is the stage, the sheet of paper is the sprite). Then you pin the photo onto the sheet of paper, but move it a little upwards and to the left before that. (The pin of the sheet of paper is now exactly in the middle of the photo.) Now, rotate the sheet of paper (the sprite) around it's pin -- et voilá! The photo rotates around its center.
It might be easier to understand with sample code:
// the image you want to rotate
SPImage *photo = [SPImage imageWithContentsOfFile:@"photo.png"];
// the sprite will contain the photo, but with an offset
// that moves the photo to its center
SPSprite *sprite = [SPSprite sprite];
photo.x = -photo.width / 2.0f;
photo.y = -photo.height / 2.0f;
[sprite addChild:photo];
// add the sprite to the stage (or whatever)
[self addChild:sprite];
// now, rotate it!
sprite.rotation = SP_D2R(45);
I hope that helps!
BTW, I already received a request to add some kind of "pivotX" and "pivotY" properties to handle this. As the Flash API does not have that either, I voted against that, but perhaps I might rethink this and add that feature in the future.
Daniel
pixelrevision
Member
Hey Daniel, I was wondering if you were still thinking about adding a registration point to sparrow for display objects. I was going to create a category, but it would require an instance variable. I thought I saw a thread where you were thinking about adding this in.
^^^ Shilo already created an tutorial/add-on showing how to do that and hopefully Daniel will add it into the official sparrow version in the next one.
@pixelrevision
What do you mean? My tutorial modifies the core of Sparrow so that you can directly change the origin (pin-point) location of an SPDisplayObject, no SPSprites necessary. I added some extra features like allowing the user to set a default origin for all display objects that are added to the stage after the default origin is changed, and so forth. I also fixed the bounds issue with it too.
That will be part of Sparrow's next release, promised 
My promise still holds! In fact, this is the next feature on my todo-list. =)
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