我正在尝试围绕圆圈旋转矩形。到目前为止,我在各个地方(主要是https://stackoverflow.com/a/4657476/861181)汇总了一些代码后,我能够围绕它的中心轴旋转矩形。
如何让它围绕圆圈旋转?
以下是我所拥有的: OverlaySelectionView.h
#import <QuartzCore/QuartzCore.h>
@interface OverlaySelectionView : UIView {
@private
UIView* dragArea;
CGRect dragAreaBounds;
UIView* vectorArea;
UITouch *currentTouch;
CGPoint touchLocationpoint;
CGPoint PrevioustouchLocationpoint;
}
@property CGRect vectorBounds;
@end
OverlaySelectionView.m
#import "OverlaySelectionView.h"
@interface OverlaySelectionView()
@property (nonatomic, retain) UIView* vectorArea;
@end
@implementation OverlaySelectionView
@synthesize vectorArea, vectorBounds;
@synthesize delegate;
- (void) initialize {
self.userInteractionEnabled = YES;
self.multipleTouchEnabled = NO;
self.backgroundColor = [UIColor clearColor];
self.opaque = NO;
self.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(rotateVector:)];
panRecognizer.maximumNumberOfTouches = 1;
[self addGestureRecognizer:panRecognizer];
}
- (id) initWithCoder: (NSCoder*) coder {
self = [super initWithCoder: coder];
if (self != nil) {
[self initialize];
}
return self;
}
- (id) initWithFrame: (CGRect) frame {
self = [super initWithFrame: frame];
if (self != nil) {
[self initialize];
}
return self;
}
- (void)drawRect:(CGRect)rect {
if (vectorBounds.origin.x){
UIView* area = [[UIView alloc] initWithFrame: vectorBounds];
area.backgroundColor = [UIColor grayColor];
area.opaque = YES;
area.userInteractionEnabled = NO;
vectorArea = area;
[self addSubview: vectorArea];
}
}
- (void)rotateVector: (UIPanGestureRecognizer *)panRecognizer{
if (touchLocationpoint.x){
PrevioustouchLocationpoint = touchLocationpoint;
}
if ([panRecognizer numberOfTouches] >= 1){
touchLocationpoint = [panRecognizer locationOfTouch:0 inView:self];
}
CGPoint origin;
origin.x=240;
origin.y=160;
CGPoint previousDifference = [self vectorFromPoint:origin toPoint:PrevioustouchLocationpoint];
CGAffineTransform newTransform =CGAffineTransformScale(vectorArea.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;
newTransform = CGAffineTransformRotate(newTransform, newAngle);
[self animateView:vectorArea 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
{
[UIView setAnimationsEnabled:YES];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.0750];
vectorArea.transform = newTransform;
[UIView commitAnimations];
}
@end
这里是试图澄清。我正在从地图上的坐标创建矩形。这是在主视图中创建该矩形的函数。基本上它是屏幕的中间位置:
overlay是使用上面的代码创建的视图。
- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
if (!circle){
circle = [MKCircle circleWithCenterCoordinate: userLocation.coordinate radius:100];
[mainMapView addOverlay:circle];
CGPoint centerPoint = [mapView convertCoordinate:userLocation.coordinate toPointToView:self.view];
CGPoint upPoint = CGPointMake(centerPoint.x, centerPoint.y - 100);
overlay = [[OverlaySelectionView alloc] initWithFrame: self.view.frame];
overlay.vectorBounds = CGRectMake(upPoint.x, upPoint.y, 30, 100);
[self.view addSubview: overlay];
}
}
以下是我想要实现的草图:
答案 0 :(得分:-1)
<强>简介强>
旋转始终围绕(0,0)进行
你已经知道的:
要围绕矩形的中心旋转,请将矩形转换为原点,旋转并平移回来。
现在提出您的问题:
要围绕圆的中心点旋转,只需移动矩形的中心,使圆圈处于(0,0)然后旋转,然后向后移动。
开始将矩形定位在12点,中心线为12.
1)如上所述,你总是围绕0,0旋转,所以将圆心移动到0,0
CGAffineTransform trans1 = CGAffineTransformTranslation(-circ.x, -circ.y);
2)按角度旋转
CGAffineTransform transRot = CGAffineTransformRotation(angle); // or -angle try out.
3)后退
CGAffineTransform transBack = CGAffineTransformTranslation(circ.x, circ.y);
将这3个旋转矩阵连接到一个组合矩阵,并将其应用于矩形。
CGAffineTransformation tCombo = CGAffineTransformConcat(trans1, transRot);
tCombo = CGTransformationConcat(tCombo, transback);
应用
rectangle.transform = tCombo;
您可能还应该阅读Quartz docu中关于转换矩阵的章节。
此代码仅使用文本编辑器编写,因此期望功能名称略有不同。