iphone:如何使用触摸事件旋转矩形图像?

问题描述

转换方形图像或圆形图像很容易...

transform a square image or round image is easy to do...

但是如果是矩形图像呢???

But what if a rectangle image ???

这是我想用触摸事件转换的图像.

This is the image I want to transform with touch event .

圆心是 (30 , 236) ，如果我触摸屏幕上的任何地方

The circle center is (30 , 236) , if I touch any place on the screen

Imageview 会将箭头转换为我的接触点.

Imageview will transform the arrow to my touch point.

但是圆心还是原来的地方.

But the circle center still the same place .

我尝试使用测试角度来转换图像

I try to transform the image use a test angle

会变成这样...

如何调整图像?

还有代码在这里

- (void)viewDidLoad {
    CGRect arrowImageRect = CGRectMake(20.0f, 20.0f, 15.0f, 220.0f);
    arrow = [[UIImageView alloc] initWithFrame:arrowImageRect];
    [arrow setImage:[UIImage imageNamed:@"arrow.png"]];
    arrow.opaque = YES;
    [self.view addSubview:arrow];
    [super viewDidLoad];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.view];
    NSLog(@"Position X: %f \n, Y: %f",touchPoint.x,touchPoint.y);
    CGAffineTransform transform = CGAffineTransformIdentity;
    arrow.transform = CGAffineTransformRotate(transform, ?????? );
}

??????部分应该是最后的解决方案......

The ?????? part should be the last solution ...

或者也许我需要调整图像视图的大小???

Or Maybe I need to resize the imageview ???

感谢您的回复或回答:-)

Thanks for any reply or answer :-)

韦伯

推荐答案

这是我认为这个问题的最终解决方案

Here is the final solution I figure this problem

检查此代码

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch=[[event allTouches]anyObject];

    [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 = arrow.center.x;
    origin.y = arrow.center.y;
    CGPoint previousDifference = [self vectorFromPoint:origin toPoint:PrevioustouchLocationpoint];
    CGAffineTransform newTransform = CGAffineTransformScale(arrow.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(@"temp1 is %f",temp1);
    //NSLog(@"Angle:%F\n",(temp1*180)/M_PI);
    newTransform = CGAffineTransformRotate(newTransform, newAngle);
    [self animateView:arrow toPosition:newTransform];
}
-(void)animateView:(UIView *)theView toPosition:(CGAffineTransform) newTransform
{
arrow.transform = newTransform;
}

-(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;
}

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