Obracanie obrazu odpowiadającego przeciągnięciu dotykiem w iPhonie

Question

Chcę obrócić obraz w kierunku zgodnym z ruchem wskazówek zegara lub przeciwnym do ruchu wskazówek zegara, odpowiadającego przeciągnięciu dotykiem użytkownika z jego prędkością. Myślę, że można to zrobić za pomocą pewnej matematyki i logiki. Jak wyglądałaby przykładowy kod?

Answer 1

Jeśli kierujesz iOS 3.2 lub nowszego, można korzystać UIRotationGestureRecognizer. Kod byłoby coś jak to wygląda:

W swojej metodzie setup (viewDidLoad lub init, etc,):

UIRotationGestureRecognizer *rotationGesture = 
    [[UIRotationGestureRecognizer alloc] initWithTarget:self 
               action:@selector(handleRotate:)]; 
rotationGesture.delegate = self; 
[myImageView addGestureRecognizer:rotationGesture]; 
[rotationGesture release]; 

obsługi zdarzenia:

- (void)handleRotate:(UIRotationGestureRecognizer *)recognizer { 
    if(recognizer.state == UIGestureRecognizerStateBegan || 
    recognizer.state == UIGestureRecognizerStateChanged) 
    { 
    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, 
                 recognizer.rotation); 
    [recognizer setRotation:0]; 
    } 
} 

Mam jeszcze kilka przykładów gest identyfikatory (w tym powyższy) na github.

Answer 2

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    for (UITouch *touch in touches) 
    { 
     currentTouch=touch; 
     if (CGRectContainsPoint([self.view frame], [touch locationInView:self.ViewRotationArrow])) 
     { 
      [self transformSpinnerwithTouches:touch]; 
     } 
     else if (!CGRectContainsPoint([ViewRotationArrow frame], [touch locationInView:self.ViewRotationArrow])) { 
      [self dispatchTouchEvent:[touch view]WithTouch:touch]; 
     } 
    } 
} 

-(void)transformSpinnerwithTouches:(UITouch *)touchLocation 
{ 
    CGPoint touchLocationpoint = [touchLocation locationInView:self.view]; 
    CGPoint PrevioustouchLocationpoint = [touchLocation previousLocationInView:self.view]; 

    //Origin is the respective point. From that I am going to measure the 
    //angle of the current position with respect to the previous position .... 
    CGPoint origin; 
    origin.x=240; 
    origin.y=160; 
    //NSLog(@"currentTouch Touch In Location In View:%F %F\n",touchLocationpoint.x,touchLocationpoint.y); 
    //NSLog(@"currentTouch Touch previous Location In View:%F %F\n",PrevioustouchLocationpoint.x,PrevioustouchLocationpoint.y); 
    CGPoint previousDifference = [self vectorFromPoint:origin toPoint:PrevioustouchLocationpoint]; 
    CGAffineTransform newTransform =CGAffineTransformScale(ViewRotationArrow.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; 
    NSLog(@"currentRotation of x %F previousRotation %F\n",currentRotation,previousRotation); 
    NSLog(@"Angle:%F\n",(temp1*180)/M_PI); 
    temp1=temp1+newAngle; 
    //NSLog(@"Angle:%F\n",(temp1*180)/M_PI); 
    newTransform = CGAffineTransformRotate(newTransform, newAngle); 
    [self animateView:ViewRotationArrow toPosition:newTransform]; 
} 

-(CGPoint)vectorFromPoint:(CGPoint)firstPoint toPoint:(CGPoint)secondPoint 
{ 
     CGPoint result; 
     CGFloat x = secondPoint.x-firstPoint.x; 
     CGFloat y = secondPoint.y-firstPoint.y; 
     result = CGPointMake(x, y); 
     return result; 
} 



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

Answer 3

-(void)rotateView 
{ 

    //shape of eclipse 

    CAShapeLayer* circle = [[CAShapeLayer alloc] init]; 
    CGMutablePathRef path = CGPathCreateMutable(); 
    CGRect ViewRect = CGRectMake(self.view.bounds.size.width/2.8, (self.view.bounds.size.height-self.view.bounds.size.width/2)/2, self.view.bounds.size.width/4, self.view.bounds.size.width/2); 
    float midX = CGRectGetMidX(ViewRect); 
    float midY = CGRectGetMidY(ViewRect); 
    CGAffineTransform t = CGAffineTransformConcat(
                CGAffineTransformConcat(
                      CGAffineTransformMakeTranslation(-midX, -midY), 
                      CGAffineTransformMakeRotation(-1.57079633/0.99)), 
                CGAffineTransformMakeTranslation(midX, midY)); 
    CGPathAddEllipseInRect(path, &t, ViewRect); 
    circle.path = path; 
    circle.frame = self.view.bounds; 
    circle.fillColor = [UIColor clearColor].CGColor; 
    circle.strokeColor = [UIColor greenColor].CGColor; 
    circle.lineWidth = 3.0f; 
    [self.view.layer addSublayer:circle]; 

    CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"]; 
    animation.duration = 0.0f; 
    animation.fromValue = [NSNumber numberWithFloat:0.0f]; 
    animation.toValue = [NSNumber numberWithFloat:1.0f]; 
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; 
    [circle addAnimation:animation forKey:@"strokeEnd"]; 


    // rotateView red color 


    testView=[[UIView alloc]init]; 
    testView.frame=CGRectMake(0, 0, 20, 20); 
    testView.backgroundColor=[UIColor redColor]; 
    testView.userInteractionEnabled=YES; 
    testView.center=CGPathGetCurrentPoint(path); 
    testView.transform = CGAffineTransformMakeRotation(1.57079633); 
    [testView sizeToFit]; 
    [self.view.layer addSublayer:testView.layer]; 


    // view Animation 

    CAKeyframeAnimation* ViewAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"]; 
    ViewAnimation.duration = 15.0f; 
    ViewAnimation.path = path; 
    ViewAnimation.rotationMode = kCAAnimationRotateAuto; 
    ViewAnimation.calculationMode = kCAAnimationCubicPaced; 
    //ViewAnimation.removedOnCompletion = NO; 
    [testView.layer addAnimation:ViewAnimation forKey:@"position"]; 

}