使用 CGAffineTransformRotate 旋转视图

Question

我有一个正在尝试旋转的圆形图像，以便黄色和黑色条纹圆圈留在用户的手指下并在两个方向上旋转。到目前为止我有这个：

- (void)handleJogShuttle:(UIPanGestureRecognizer *)recognizer {

    UIView *shuttle = [recognizer view];

    if ([recognizer state] == UIGestureRecognizerStateBegan ||
        [recognizer state] == UIGestureRecognizerStateChanged) {

        [recognizer view].transform = CGAffineTransformRotate([[recognizer view] transform],M_PI / 20.0f);
        [recognizer setTranslation:CGPointZero inView:[shuttle superview]];
    }
}

此外，目前，最轻微的移动都会导致视图旋转一整圈，这显然是不希望的。

Answer 1

#import "RotationTestViewController.h"

@interface RotationTestViewController()
-(void)transformSpinnerwithTouches:(UITouch *)touchLocation;
-(CGPoint)vectorFromPoint:(CGPoint)firstPoint toPoint:(CGPoint)secondPoint;
-(void)animateView:(UIView *)theView toPosition:(CGAffineTransform) newTransform;
@end
@implementation RotationTestViewController

- (void)viewDidLoad {
[super viewDidLoad];}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches)
    {
        // Send to the dispatch method, which will make sure the appropriate subview is acted upon
        //    currentTouch=touch;
    }
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches){
        // Sends to the dispatch method, which will make sure the appropriate subview is acted upon
    }
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch=[[event allTouches]anyObject];
    if (touch.view==Spinner)
    {
        [self transformSpinnerwithTouches:touch];
    }
}

-(void)transformSpinnerwithTouches:(UITouch *)touchLocation
{
    CGPoint touchLocationpoint = [touchLocation locationInView:self.view];
    CGPoint PrevioustouchLocationpoint = [touchLocation previousLocationInView:self.view];
    //origin is the respective piont from that i gonna measure the angle of the current position with respective to previous position ....
    CGPoint origin;
    origin.x=Spinner.center.x;
    origin.y=Spinner.center.y;
    CGPoint previousDifference = [self vectorFromPoint:origin toPoint:PrevioustouchLocationpoint];
    CGAffineTransform newTransform =CGAffineTransformScale(Spinner.transform, 1, 1);
    CGFloat previousRotation = atan2(previousDifference.y, previousDifference.x);
    CGPoint currentDifference = [self vectorFromPoint:origin toPoint:touchLocationpoint];
    CGFloat currentRotation = atan2(currentDifference.y, currentDifference.x);
    CGFloat newAngle = currentRotation- previousRotation;
    temp1=temp1+newAngle;
    NSLog(@"Angle:%F\n",(temp1*180)/M_PI);
    newTransform = CGAffineTransformRotate(newTransform, newAngle);
    [self animateView:Spinner toPosition:newTransform];
}

-(void)animateView:(UIView *)theView toPosition:(CGAffineTransform) newTransform
{
    [UIView setAnimationsEnabled:YES];
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationCurve:UIViewAnimationCurveLinear];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:0.0750];
    Spinner.transform = newTransform;
    [UIView commitAnimations];
}

//-(CGFloat)distanceFromPoint:(CGPoint)fromPoint toPoint:(CGPoint)toPoint
//
//{
//float x = toPoint.x - fromPoint.x;
//float y = toPoint.y - fromPoint.y;
//return hypot(x, y);
//}

-(CGPoint)vectorFromPoint:(CGPoint)firstPoint toPoint:(CGPoint)secondPoint
{
    CGFloat x = secondPoint.x - firstPoint.x;
    CGFloat y = secondPoint.y - firstPoint.y;
    CGPoint result = CGPointMake(x, y);
    //NSLog(@"%f %f",x,y);
    return result;
}

-(void) dealloc
{
    [Spinner release];
    [super dealloc];
}

Answer 2

我怀疑这个方法被多次调用。尝试使用 NSLog 并检查它执行了多少次。
无论如何，您没有正确计算角度，您可以尝试使用

-(CGPoint)translationInView:(UIView *)view

识别器来计算正确的旋转角度。