ios - How To Get A Perfect Position Of Rotating View? -


i have 1 view , rotating view using cabasicanimation. problem how perfect position of view while rotating. have tried many type of codes can't got perfect position during rotation of view.

cabasicanimation *rotationanimation = [cabasicanimation animationwithkeypath:@"transform.rotation.z"]; nsnumber *currentangle = [circleview.layer.presentationlayer valueforkeypath:@"transform.rotation"]; rotationanimation.fromvalue = currentangle; rotationanimation.tovalue = @(50*m_pi); rotationanimation.duration = 50.0f;             // might fast rotationanimation.repeatcount = huge_valf;     // huge_valf defined in math.h import [circleview.layer addanimation:rotationanimation forkey:@"rotationanimationleft"];

i using code rotating view.

i have attached 1 photo of view.

thank in advance please if know.

enter image description here

to view's parameters during animation should use view.layer.presentationlayer

added:

in order coordinate of top left corner of view, use following code:

- (cgpoint)currenttopleftpointoftheview:(uiview *)view {     cgrect rect = view.bounds;     rect.origin.x = view.center.x - 0.5 * cgrectgetwidth(rect);     rect.origin.y = view.center.y - 0.5 * cgrectgetheight(rect);      cgpoint originaltopleftcorner = cgpointmake(cgrectgetminx(rect), cgrectgetminy(rect));     cgpoint rectcenter = cgpointmake(cgrectgetmidx(rect), cgrectgetmidy(rect));     cgfloat radius = sqrt(pow(rectcenter.x - originaltopleftcorner.x, 2.0) + pow(rectcenter.y - originaltopleftcorner.y, 2.0));      cgfloat originalangle = m_pi - acos((rectcenter.x - originaltopleftcorner.x) / radius);      catransform3d currenttransform = ((calayer *)view.layer.presentationlayer).transform;     cgfloat rotation = atan2(currenttransform.m12, currenttransform.m11);      cgfloat resultangle = originalangle - rotation;     cgpoint currenttopleftcorner = cgpointmake(round(rectcenter.x + cos(resultangle) * radius), round(rectcenter.y - sin(resultangle) * radius));      return currenttopleftcorner; }

resulting cgpoint coordinate of top left corner of (rotated) view relative superview.


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