如何使用子视图调整UIView的大小

Question

我的目标是用句柄调整UIView的大小 - 它的子视图。 我让我的项目完美地完成了这个任务：句柄有一个PanGestureRecognizer，它的处理程序方法使用以下方法调整视图（父级）的大小：

-(IBAction)handleResizeGesture:(UIPanGestureRecognizer *)recognizer {

  CGPoint touchLocation = [recognizer locationInView:container.superview];
  CGPoint center = container.center;

  switch (recognizer.state) {
    case UIGestureRecognizerStateBegan: {
        deltaAngle = atan2f(touchLocation.y - center.y, touchLocation.x - center.x) - 
                            CGAffineTransformGetAngle(container.transform);
        initialBounds = container.bounds;
        initialDistance = CGPointGetDistance(center, touchLocation);
        break;
    }

    case UIGestureRecognizerStateChanged: {
        CGFloat scale = CGPointGetDistance(center, touchLocation)/initialDistance;
        CGFloat minimumScale = self.minimumSize/MIN(initialBounds.size.width,   
                                                   initialBounds.size.height);
        scale = MAX(scale, minimumScale);
        CGRect scaledBounds = CGRectScale(initialBounds, scale, scale);
        container.bounds = scaledBounds;

        [container setNeedsDisplay];

        break;
    }

    case UIGestureRecognizerStateEnded:

        break;

    default:
        break;
  }
}

请注意，我使用中心和边界属性，因为当将变换应用于我的视图时，帧不可靠。

但是，我的要求实际上是在任何方向调整视图大小 - 不仅按照代码的比例调整大小。 问题是我没有找到正确的方法或方法，这个句柄可以如何调整其超视图的边界（宽度或高度），因此它总是粘在角落，而手指拖动它。

如果我更容易理解我的意思，这是我的项目 。

如下面的答案所建议的更新解决方案效果非常好但是一旦应用了变换（例如在viewDidLoad中我有container.transform = CGAffineTransformMakeRotation(90); ）它不会：

    case UIGestureRecognizerStateBegan: {
        initialBounds = container.bounds;
        initialDistance = CGPointGetDistance(center, touchLocation);
        initialDistanceX = CGPointGetDistanceX(center, touchLocation);
        initialDistanceY = CGPointGetDistanceY(center, touchLocation);
        break;
    }

    case UIGestureRecognizerStateChanged: {

        CGFloat scaleX = abs(center.x-touchLocation.x)/initialDistanceX;
        CGFloat scaleY = abs(center.y-touchLocation.y)/initialDistanceY;
        CGFloat minimumScale = self.minimumSize/MIN(initialBounds.size.width, initialBounds.size.height);
        scaleX = MAX(scaleX, minimumScale);
        scaleY = MAX(scaleY, minimumScale);
        CGRect scaledBounds = CGRectScale(initialBounds, scaleX, scaleY);
        container.bounds = scaledBounds;
        [container setNeedsDisplay];

        break;
    }

哪里

CG_INLINE CGFloat CGPointGetDistanceX(CGPoint point1, CGPoint point2) {
  return (point2.x - point1.x);
}
CG_INLINE CGFloat CGPointGetDistanceY(CGPoint point1, CGPoint point2) {
  return (point2.y - point1.y);
}

Answer 1

您在调用CGRectScale时设置了相同的scale参数（initialBounds，scale，scale）; 试试这个：

case UIGestureRecognizerStateChanged: {
            CGFloat scaleX = abs(center.x-touchLocation.x)/initialDistance;
            CGFloat scaleY = abs(center.y-touchLocation.y)/initialDistance;
            CGFloat minimumScale = self.minimumSize/MIN(initialBounds.size.width, initialBounds.size.height);
            scaleX = MAX(scaleX, minimumScale);
            scaleY = MAX(scaleY, minimumScale);
            CGRect scaledBounds = CGRectScale(initialBounds, scaleX, scaleY);
            container.bounds = scaledBounds;

            [container setNeedsDisplay];

            break;

您还可以考虑存储initialDistanceX和initialDistanceY。

Answer 2

使用UIPinchGestureRecognizer和UIPanGestureRecognizer 。

试试这个代码

    //--Create and configure the pinch gesture
    UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGestureDetected:)];
    [pinchGestureRecognizer setDelegate:self];
    [container.superview addGestureRecognizer:pinchGestureRecognizer];

    //--Create and configure the pan gesture
    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureDetected:)];
    [panGestureRecognizer setDelegate:self];
    [container.superview addGestureRecognizer:panGestureRecognizer];

对于UIPinchGestureRecognizer ：

- (void)pinchGestureDetected:(UIPinchGestureRecognizer *)recognizer
{

    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGFloat scale = [recognizer scale];
        [recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, scale, scale)];
        [recognizer setScale:1.0];
        panGesture = YES;
    }
}

对于UIPanGestureRecognizer：

- (void)panGestureDetected:(UIPanGestureRecognizer *)recognizer
{
    UIGestureRecognizerState state = [recognizer state];
    if (panGesture==YES)
    {
    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGPoint translation = [recognizer translationInView:recognizer.view];
        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
        [recognizer setTranslation:CGPointZero inView:recognizer.view];
    }}
}

Answer 3

我不用子视图来控制它。 将变换应用于外部视图时会变得混乱。 只需将两个视图添加到ViewController，并使用一些代码将它们连接起来。 我已经改变了项目， 在GitHub上找到了test-001 。

ViewController代码可以为空。

要转换的视图TransformableView需要一个scale属性，以及一个应用它的方法（如果你想要添加其他转换）。

@interface TransformableView : UIView

@property (nonatomic) CGSize scale;
-(void)applyTransforms;

@end

---

@implementation TransformableView

-(void)applyTransforms
{
    // Do whatever additional transform you want (e.g. concat additional rotations / mirroring to the transform).
    self.transform =  CGAffineTransformMakeScale(self.scale.width, self.scale.height);
}

@end

DraggableCorner可以管理其余的（使用一些基本的数学运算）。

@class TransformableView;
@interface DraggableCorner : UIView

@property (nonatomic, weak) IBOutlet TransformableView *targetView; // Hook up in IB.
-(IBAction)panGestureRecognized:(UIPanGestureRecognizer*) recognizer;

@end

---

CG_INLINE CGPoint offsetOfPoints(CGPoint point1, CGPoint point2)
{ return (CGPoint){point1.x - point2.x, point1.y -point2.y}; }

CG_INLINE CGPoint addPoints(CGPoint point1, CGPoint point2)
{ return (CGPoint){point1.x + point2.x, point1.y + point2.y}; }


@interface DraggableCorner ()
@property (nonatomic) CGPoint touchOffset;
@end


@implementation DraggableCorner


-(IBAction)panGestureRecognized:(UIPanGestureRecognizer*) recognizer
{
    // Location in superview.
    CGPoint touchLocation = [recognizer locationInView:self.superview];

    // Began.
    if (recognizer.state == UIGestureRecognizerStateBegan)
    {
        // Finger distance from handler.
        self.touchOffset = offsetOfPoints(self.center, touchLocation);
    }

    // Moved.
    if (recognizer.state == UIGestureRecognizerStateChanged)
    {
        // Drag.
        self.center = addPoints(touchLocation, self.touchOffset);

        // Desired size.
        CGPoint distanceFromTargetCenter = offsetOfPoints(self.center, self.targetView.center);
        CGSize desiredTargetSize = (CGSize){distanceFromTargetCenter.x * 2.0, distanceFromTargetCenter.y * 2.0};

        // -----
        // You can put limitations here, simply clamp `desiredTargetSize` to some value.
        // -----

        // Scale needed for desired size.
        CGSize targetSize = self.targetView.bounds.size;
        CGSize targetRatio = (CGSize){desiredTargetSize.width / targetSize.width, desiredTargetSize.height / targetSize.height};

        // Apply.
        self.targetView.scale = targetRatio;
        [self.targetView applyTransforms];
    }
}

在IB中设置类，并连接IBAction和DraggableView的IBOutlet 。