ios - CGAffineTransformMakeRotation -

i'm learning use cgaffinetransformmakerotation can't work, have searched on web , can't find solution

i making clock, when test arrow doesn't rotate straight, moves @ same time.

-(void)tick{  nscalendar *calender = [[nscalendar alloc]initwithcalendaridentifier:nsgregoriancalendar];  nsuinteger units = nshourcalendarunit|nsminutecalendarunit|nssecondcalendarunit;  nsdatecomponents *components = [calender components:units fromdate:[nsdate date]];  cgfloat secsangle = components.second*m_pi*2.0/60;  self.secondhand.transform = cgaffinetransformmakerotation(secsangle);  } 

thanks in advance :)

first of all, when testing, use known value, m_pi/2.0, instead of secsangle anything.

second, keep in mind rotation around center of view/layer default. can change that, it's change it.