QuartZ2D __ 简单用法 1

转载自：http://www.cnblogs.com/guosir/p/5389239.html

一. 简单做一个画板

1. 建立一个UIView类

2. 在.m里建立一个延展

3. 分别定义一个起点, 一个终点的结构体属性 . 在建立一个存储路径的数组

@interface DrawView (){    CGPoint _startPoint;    CGPoint _endPoint;}@property (nonatomic, strong) NSMutableArray *pathArray;@end

4. 懒加载数组

- (NSMutableArray *)pathArray{    if (_pathArray == nil) {        _pathArray = [NSMutableArray array];    }    return _pathArray;}

5. 开始绘制

(1) 起点

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    // 获取起点    _startPoint = [[touches anyObject] locationInView:self];        // 创建贝瑟尔路径    UIBezierPath *path = [UIBezierPath bezierPath];    // 起点    [path moveToPoint:_startPoint];        // 添加到数组中    [self.pathArray addObject:path];        }

(2) 终点

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    _endPoint = [[touches anyObject] locationInView:self];        // 终点    UIBezierPath *path = [self.pathArray lastObject];        [path addLineToPoint:_endPoint];        [self setNeedsDisplay];}

6. 重写  - (void)drawRect:(CGRect)rect 方法

- (void)drawRect:(CGRect)rect {    // Drawing code        for (UIBezierPath *path in self.pathArray) {        // 设置颜色        [[UIColor orangeColor] set];        // 设置粗度        path.lineWidth = 10;        // 渲染        [path stroke];    }        }

二. 绘制饼状图

注 : 为了好看, 我随即分成了大小颜色都不同的99份

代码实现

#import "DrawView.h"#define kcolor arc4random()% 256 / 255.0@implementation DrawView// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code        NSMutableArray *array = [NSMutableArray array];    int sum = 0;    for (int i = 1; i< 100; i ++) {        int num = arc4random()% 100 ;        sum += num;        NSNumber *number = [NSNumber numberWithInt:num];        [array addObject:number];    }    // 记录起点和终点    CGFloat start = 0;    CGFloat end = 0;    // 遍历数据    for (NSNumber *num in array) {                end = num.floatValue / sum * M_PI * 2;                UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:start endAngle:start + end clockwise:YES];        // 关闭路径        [path addLineToPoint:CGPointMake(150, 150)];                [[UIColor colorWithRed:kcolor green:kcolor blue:kcolor alpha:1] set];        [path closePath];        [path fill];        start += end;                    }@end 

三. 截图用法

1. 首先要有一个imageView, 所以在ViewContorller先建立一个UIImageView的属性 将背景的图片设置出来

2. 建立一个继承自UIView的类

3. 在这个UIView类.m里实现截图 (.h中写了一个block块用于传递路径)

.h 代码实现

// 传递路径typedef void(^block)(UIBezierPath *p);@interface MyView : UIView@property (nonatomic, copy) block myblock;@end

.m 代码实现

#import "MyView.h"@interface MyView ()// 保存路径@property (nonatomic, strong) NSMutableArray *pathArray;@end@implementation MyView- (NSMutableArray *)pathArray{    if (! _pathArray) {        _pathArray = [NSMutableArray array];    }    return _pathArray;}- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    // 1. 获取起始点 并且创建路径    UIBezierPath *path = [UIBezierPath bezierPath];    [path moveToPoint:[[touches anyObject] locationInView:self]];        // 2. 装入数组    [self.pathArray addObject:path];    }- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    // 1. 获取终点 (不止一个)    UIBezierPath *path = [self.pathArray lastObject];    [path addLineToPoint:[[touches anyObject] locationInView:self]];        // 2. 调用drawrect    [self setNeedsDisplay];    }- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    // 封闭路径    UIBezierPath *path = [self.pathArray lastObject];    [path closePath];        [self setNeedsDisplay];    // 调用block路径    self.myblock(path);}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code    for (UIBezierPath *path in self.pathArray) {        path.lineWidth = 2;        [[UIColor orangeColor] set];        [path stroke];    }}@end

4. 在ViewController中中回调路径

#import "ViewController.h"#import "MyImageView.h"#import "MyView.h"@interface ViewController ()@property (nonatomic, strong) UIImageView *imageView;@property (nonatomic, strong) MyView *myView;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // 获取图片    // __block全局区   __block UIImage *image = [UIImage imageNamed:@"0"];    self.imageView = [[UIImageView alloc] initWithImage:image];    _imageView.frame = CGRectMake(7, 160, image.size.width, image.size.height);    [self.view addSubview: _imageView];        self.myView = [[MyView alloc] initWithFrame:self.imageView.frame];    _myView.backgroundColor = [UIColor colorWithRed:1 green:1 blue:1 alpha:0];    [self.view addSubview:_myView];        // 剪切        __weak typeof(self) weakSelf = self;    _myView.myblock = ^(UIBezierPath *p){                // 获取上下文        UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);        // 路径        UIBezierPath *path = p;        // 剪切        [path addClip];        // 绘制        [image drawAtPoint:CGPointZero];        // 获取剪切后的图片        image = UIGraphicsGetImageFromCurrentImageContext();        // 结束上下文        UIGraphicsEndImageContext();        // 给imageView赋值        weakSelf.imageView.image = image;            };}    @end