ios - 拖动、缩放和旋转多个 UIImageview

Question

到目前为止，我可以移动、缩放和旋转所有对象，但多个对象都会一起移动。我想让他们分开搬。我想我必须将 objectatIndex 更改为 1，但它只是崩溃了。

我使用了以下代码:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    NSArray *allTouches = [touches allObjects];

    UITouch* t;
    if([[event allTouches] count]==1){
        if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView])) {
            t=[[[event allTouches] allObjects] objectAtIndex:0];
            touch1=[t locationInView:nil];
        }
    }else{
        t=[[[event allTouches] allObjects] objectAtIndex:0];
        touch1=[t locationInView:nil];
        t=[[[event allTouches] allObjects] objectAtIndex:1];
        touch2=[t locationInView:nil];
    }
}

-(double)distance:(CGPoint)point1 toPoint:(CGPoint)point2
{
    double deltaX, deltaY;
    deltaX = point1.x - point2.x;
    deltaY = point1.y - point2.y;
    return sqrt(deltaX * deltaX + deltaY * deltaY);
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    CGPoint currentTouch1;
    CGPoint currentTouch2;
    NSArray *allTouches = [touches allObjects];
    UITouch* t;
    float scale,rotation;

    if([[event allTouches] count]==1){
        t=[[[event allTouches] allObjects] objectAtIndex:0];
        if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
        { 
            touch2=[t locationInView:nil];
            Birdie.center=CGPointMake(Birdie.center.x+touch2.x-touch1.x,Birdie.center.y+touch2.y-touch1.y);
            imageViewauto.center=CGPointMake(imageViewauto.center.x+touch2.x-touch1.x,imageViewauto.center.y+touch2.y-touch1.y);
            touch1=touch2;
        }
    }
    else if([[event allTouches] count]==2)
    {
        t=[[[event allTouches] allObjects] objectAtIndex:0];
        currentTouch1=[t locationInView:nil];

        t=[[[event allTouches] allObjects] objectAtIndex:1];
        currentTouch2=[t locationInView:nil];

        double distance1 =  [self distance:currentTouch1 toPoint:currentTouch2];
        double distance2 = [self distance:touch1 toPoint:touch2];

        if (distance2 == 0)
        {
            //handle the case where distance is zero
        }
        else {
            scale =distance1 / distance2;}

        rotation=atan2(currentTouch2.y-currentTouch1.y, currentTouch2.x-currentTouch1.x)-atan2(touch2.y-touch1.y,touch2.x-touch1.x);
        if(isnan(scale)){
            scale=1.0f;
        }
        NSLog(@"rotation %f",rotation);

        NSLog(@"scale %f",scale);

        if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
        {

            Birdie.transform=CGAffineTransformScale(Birdie.transform, scale,scale);
            Birdie.transform=CGAffineTransformRotate(Birdie.transform, rotation);

            imageViewauto.transform=CGAffineTransformScale(imageViewauto.transform, scale,scale);
            imageViewauto.transform=CGAffineTransformRotate(imageViewauto.transform, rotation);
        }
        else // In case of scaling or rotating the background imageView
        {
            imageView.transform=CGAffineTransformScale(imageView.transform, scale,scale);
            imageView.transform=CGAffineTransformRotate(imageView.transform, rotation);
        }

        touch1=currentTouch1;
        touch2=currentTouch2;
    }
}

Answer 1

首先，处理拖动、缩放和旋转的一种简单方法是使用 GestureRecognizers，如下所示:

    UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
[pinchRecognizer setDelegate:self];
[self.view addGestureRecognizer:pinchRecognizer];

UIRotationGestureRecognizer *rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
[rotationRecognizer setDelegate:self];
[self.view addGestureRecognizer:rotationRecognizer];

UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[self.view addGestureRecognizer:panRecognizer];

UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setDelegate:self];
[self.view addGestureRecognizer:tapRecognizer];

要处理多个 UIImageView，您可以使用触摸点的位置，您可以使用以下函数来执行此操作:

- (CGPoint)locationInView:(UIView*)view;   
- (CGPoint)locationOfTouch:(NSUInteger)touchIndex inView:(UIView*)view;

根据触摸的次数，您可以使用第一个或第二个函数，然后查看触摸点是否在所考虑的 UIImageView 的框架内，例如，对于缩放，您可以执行如下所示的操作:

-(void)scale:(id)sender {

UIView * pinchView = [(UIPinchGestureRecognizer*)sender view];

CGPoint first_point = [sender locationOfTouch:0 inView:pinchView];
CGPoint second_point = [sender locationOfTouch:1 inView:pinchView];


if (CGRectContainsPoint(my_image_view.frame, first_point) && CGRectContainsPoint(my_image_view.frame, second_point)) {
    [self.view bringSubviewToFront:pinchView];

    if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

        lastScale = 1.0;
        return;
    }

    CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);

    CGAffineTransform currentTransform = my_image_view.transform;
    CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
    [my_image_view setTransform:newTransform];

    lastScale = [(UIPinchGestureRecognizer*)sender scale];}}