CGAffineTransformIdentity时如何调整UIView的大小 [英] How to resize the UIView when CGAffineTransformIdentity

问题描述

我正在做一个具有旋转和调整视图大小功能的应用程序.我已经实现了此功能，但确实遇到了问题.

I am doing an app which has a feature to rotate and re size a view. i have implemented this feature but i do face an issue.

我的问题

拖动视图的四个角时，将调整视图的大小，调整大小后，我可以在两个方向上旋转视图.

The View wil be resized when dragging its four corners, after resizing it i can rotate the view in both directions.

旋转完成后，如果我再次尝试通过拖动其角来调整视图的大小，则视图的大小将变为不可预测的值，并且会在屏幕上四处移动.

Once the rotation is done, if i try again to resize the view by dragging its corner, the view's size gone to unpredictable value and its moving all around the screen.

我终于用谷歌搜索了以下解决方案

I googled lot finally i got the following solution

The frame property is undefined when transform != CGAffineTransformIdentity, as per the docs on UIView

我看到一个应用程序已经完全实现了我希望实现的功能.

I saw one app which has implemented the feature exactly what i wish to implement.

旋转UIView后如何调整UIView的大小

How can i resize the UIView after rotation of UIView

我用于调整视图大小的代码

开始触摸

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

   UITouch *touch = [[event allTouches] anyObject];

   NSLog(@"[touch view]:::%@",[touch view]);

   touchStart = [[touches anyObject] locationInView:testVw];
   isResizingLR = (testVw.bounds.size.width - touchStart.x < kResizeThumbSize &&     testVw.bounds.size.height - touchStart.y < kResizeThumbSize);
   isResizingUL = (touchStart.x <kResizeThumbSize && touchStart.y <kResizeThumbSize);
   isResizingUR = (testVw.bounds.size.width-touchStart.x < kResizeThumbSize &&      touchStart.y<kResizeThumbSize);
   isResizingLL = (touchStart.x <kResizeThumbSize && testVw.bounds.size.height -touchStart.y <kResizeThumbSize);    
}

触摸移动

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
CGPoint touchPoint = [[touches anyObject] locationInView:testVw];
CGPoint previous=[[touches anyObject]previousLocationInView:testVw];

float  deltaWidth = touchPoint.x-previous.x;
float  deltaHeight = touchPoint.y-previous.y;

NSLog(@"CVTM:%@",NSStringFromCGRect(testVw.frame));


if (isResizingLR) {
 testVw.frame = CGRectMake(testVw.frame.origin.x, testVw.frame.origin.y,touchPoint.x +   deltaWidth, touchPoint.y + deltaWidth);
 }  
if (isResizingUL) {
 testVw.frame = CGRectMake(testVw.frame.origin.x + deltaWidth, testVw.frame.origin.y +  deltaHeight, testVw.frame.size.width - deltaWidth, testVw.frame.size.height - deltaHeight);
 } 
if (isResizingUR) {
  testVw.frame = CGRectMake(testVw.frame.origin.x ,testVw.frame.origin.y + deltaHeight,  testVw.frame.size.width + deltaWidth, testVw.frame.size.height - deltaHeight);      
 } 
if (isResizingLL) {
 testVw.frame = CGRectMake(testVw.frame.origin.x + deltaWidth ,testVw.frame.origin.y ,  testVw.frame.size.width - deltaWidth, testVw.frame.size.height + deltaHeight);   
}

if (!isResizingUL && !isResizingLR && !isResizingUR && !isResizingLL) {
testVw.center = CGPointMake(testVw.center.x + touchPoint.x - touchStart.x,testVw.center.y + touchPoint.y - touchStart.y);
 }

 }

推荐答案

由于您不使用UIView动画，因此可以保存当前视图的变换，将视图的变换设置为身份，调整视图的大小并重新应用保存的变换:

Since you don't use UIView animations you can save current view's transform, set view's transform to identity, resize the view and reapply saved transform:

UIView *v;
CGAffineTransform t = v.transform;
v.transform = CGAffineTransformIdentity;
CGFloat scale = 2.0f;
v.frame = CGRectMake(v.frame.origin.x, v.frame.origin.y, v.frame.size.width*scale , v.frame.size.height*scale);
v.transform = t;

(编辑)关于您调整大小:

(EDIT)About your resizing:

如果您使用4个向量(点)A，B，C，D定义矩形，其中(A+C)*.5 = (B+D)*.5 = rectangle_center然后将点C移动到位置C'也会将B和D移动到B'和D':

If you define your rectangle with 4 vectors (points) A,B,C,D where (A+C)*.5 = (B+D)*.5 = rectangle_center Then for moving point C to position C' would also move B and D to B' and D':

A' = A
C' = C' //touch input
B' = A + (normalized(B-A) * dotProduct((C'-A), normalized(B-A)))
D' = A + (normalized(D-A) * dotProduct((C'-A), normalized(D-A)))

之后:

• 将您的观点转变为身份
• 将框架设置为(.0f, .0f, length(A-D), length(A-C))
• 将中心设置为(A+D)*.5f
• 通过atanf(height/width)进行旋转以创建视图的变换，并使用normalized(D-A)和normalized(B-A)
的基本矢量填充少数"if"或进行填充/创建变换

• transform your view to identity
• set frame to (.0f, .0f, length(A-D), length(A-C))
• set center to (A+D)*.5f
• get rotation to create view's transform through atanf(height/width) and few "if's" OR fill/create transform with base vectors that are normalized(D-A) and normalized(B-A)

您可以对矩形中的任何点执行此操作.

You can do that for any point in a rectangle.

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