CAShapeLayer的使用[1]

CAShapeLayer的使用[1]

使用CoreAnimation绘制动画带来的系统开销非常的小,CoreAnimation通常都是使用GPU的.

CAShapeLayer属于CoreAnimation中很重要的一种layer,无论是作为mask还是作为进度条显示都非常的好用,我用CAShapeLayer实现了如下复杂的效果.

//

//  RootViewController.m

//

//  Copyright (c) 2014年 Y.X. All rights reserved.

//

#import "RootViewController.h"

#import "UIImage+ImageEffects.h"
@interface RootViewController ()
@property (nonatomic, strong) UIView        *showView;

@property (nonatomic, strong) CAShapeLayer  *oneReferenceLayer;

@property (nonatomic, strong) CAShapeLayer  *maskLayer;
@end
#define   DEGREES(degrees)  ((M_PI * (degrees))/ 180.f)
@implementation RootViewController
- (void)handlePan:(UIPanGestureRecognizer *)recognizer

{

    // 拖拽

    CGPoint translation = [recognizer translationInView:self.view];

    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,

                                         recognizer.view.center.y + translation.y);

    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
// 关闭CoreAnimation实时动画绘制(核心)

    [CATransaction setDisableActions:YES];

    _maskLayer.position = recognizer.view.center;

}
- (void)viewDidLoad

{

    [super viewDidLoad];
/* ====== 背景View ====== */

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.view.bounds];

    imageView.image = [UIImage imageNamed:@"back"];

    [self.view addSubview:imageView];
/* ====== 作为mask的View ====== */

    _maskLayer = [CAShapeLayer layer];
// 贝塞尔曲线(创建一个圆)

    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(0, 0)

                                                        radius:100

                                                    startAngle:DEGREES(0)

                                                      endAngle:DEGREES(360)

                                                     clockwise:YES];

    // 获取path

    _maskLayer.path     = path.CGPath;

    _maskLayer.position = CGPointMake(_showView.bounds.size.width/2.f,

                                      _showView.bounds.size.height/2.f);

    // 设置填充颜色为透明

    _maskLayer.fillColor = [UIColor blackColor].CGColor;

    _maskLayer.position = self.view.center;
UIView *blurView = [[UIView alloc] initWithFrame:self.view.bounds];

    blurView.backgroundColor = [UIColor blackColor];

    [self.view addSubview:blurView];

    blurView.layer.mask = _maskLayer;

    blurView.layer.contents = (__bridge id)([[UIImage imageNamed:@"back"] blurImage].CGImage);
/* ====== 透明的View,用于maskView中的ShapeLayer的参考View(用于拖拽) ====== */

    _showView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];

    _showView.backgroundColor = [UIColor clearColor];

    _showView.center = self.view.center;

    [self.view addSubview:_showView];
UIPanGestureRecognizer *recognizer =     [[UIPanGestureRecognizer alloc] initWithTarget:self

                                            action:@selector(handlePan:)];

    [_showView addGestureRecognizer:recognizer];

}
@end

这个地方很关键哦,没有关闭的话会非常的卡顿的.

shapeLayer作为mask的一些技巧.

CAShapeLayer的使用[1],布布扣,bubuko.com