15~16day-Quartz2D(自定义控件、图片水印、裁剪以及屏幕截图)

前言

掌握
1、- (void)drawRect:(CGRect)rect;的使用
2、常见图形的绘制
3、绘图状态的设置：文字颜色、线宽
4、图形上下文状态的保持、恢复
5、图形上下文
6、矩阵操作
7、quartz 2D 的内存管理
8、图片水印、裁剪以及屏幕的截图

一、什么是quartz 2D

quartz 2D是一个二维绘图引擎，同时支持iOS、Mac系统

1、quartz 2D能完成的工作
1》绘制图形、文字
2》绘制、生成图片（图像）
3》读取、生成PDF文件
4》图片的裁截：圆形裁剪
5》自定义控件
2、quartz 2D在iOS开发中的价值
当使用uikit框架的普通控件无法实现需求的时候，可采用quartz 2D技术将 控件内部的结构画出来 ，自定义UI控件的样子

3、 Quartz2D须知

1）Quartz2D的API是纯C语言的
2）Quartz2D的API来自于Core Graphics框架
3）数据类型和函数基本都以CG作为前缀：CGContextRef、CGPathRef、CGContextStrokePath(ctx);
4、 Quartz 2D绘图的基础元素——路径

1）路径定义了一条或者或多条形状或子路径
2）子路径可以包含一条或者多条直线或曲线
3）子路径也可以是一些简单的形状，例如线、圆形、矩形或者星型等
4）子路径还可以包含复杂的形状，例如地图轮廓或者涂鸦等
5）路径可以是开放的，也可以是封闭的
6）路径主要使用在定义视图运动轨迹
4、quartz 2D 的内存管理
1、如果含有create、copy的函数创建对象，使用完之后必须释放，否则将导致内测泄露
2、如果retain了一个对象，不在使用时需将其release掉
1》可以使用quart 2D的函数（e g. CGColorSpaceRetain）来指定retain\release一个对象，或者使用core foundation 的CFRetain.

二、图形上下文（graphics context）

是一个CGContextRef类型数据
1、作用
1》保持绘图的信息
2》决定绘图的输出目标（PDF、bitmap、layer、printer、window）

p s:相同的一套绘图序列，指定不同的Graphics Context，就可将相同的图像绘制到不同的目标上

2、分类
Quartz2D提供了以下几种类型的Graphics Context：

Bitmap Graphics Context
PDF Graphics Context
Window Graphics Context
Layer Graphics Context
Printer Graphics Context

3、 图形上下文栈的操作

//将当前的上下文copy一份,保存到栈顶(那个栈叫做”图形上下文栈”)
void CGContextSaveGState(CGContextRef c)
//将栈顶的上下文出栈,替换掉当前的上下文
void CGContextRestoreGState(CGContextRef c)
- (void)drawRect:(CGRect)rect{

    CGContextRef context= UIGraphicsGetCurrentContext();

    //Pushes a copy of the current graphics state onto the graphics state stack for the context.

    CGContextSaveGState(context);

    //设置绘制信息

    UIBezierPath *path = [UIBezierPath bezierPath];

    [path moveToPoint:CGPointMake(10, 125)];

    [path addLineToPoint:CGPointMake(240, 125)];

    CGContextAddPath(context, path.CGPath);

    //设置绘图状态

    [[UIColor redColor] set];

    //渲染

    CGContextStrokePath(context);

    //绘制第二条线

    UIBezierPath *path1 = [UIBezierPath bezierPath];

    [path1 moveToPoint:CGPointMake(125, 10)];

    [path1 addLineToPoint:CGPointMake(125, 240)];



    CGContextAddPath(context, path1.CGPath);//Adds a previously created Quartz path object to the current path in a graphics context.

    //Sets the current graphics state to the state most recently saved.设置绘图状态为最近保存的上下文状态

    CGContextRestoreGState(context);

    CGContextStrokePath(context); 

}

三、自定义控件

1、如何利用Quartz2D绘制东西到view上？
(1)首先，得有图形上下文，因为它能保存绘图信息，并且决定着绘制到什么地方去
(2)其次，那个图形上下文必须跟view相关联，才能将内容绘制到view上面
2、自定义UI控件的步骤
1）新建一个类，继承自UIView
2）实现- (void)drawRect:(CGRect)rect方法，然后在这个方法中，可以：
(1)取得跟当前view相关联的图形上下文
(2)绘制相应的图形内容，绘制时产生的线条称为路径。 路径由一个或多个直线段或曲线段组成。
(3)利用图形上下文将绘制的所有内容渲染显示到view上面
也可以：利用UIKit封装的绘图函数直接绘图
3、drawRect:方法在什么时候被调用？
(1)当view第一次显示到屏幕上时（被加到UIWindow上显示出来）
(2)调用view的setNeedsDisplay或者setNeedsDisplayInRect:时
4、 drawRect:中取得的上下文（Layer Graphics Context）

在drawRect:方法中取得上下文后，就可以绘制东西到view上
1）View内部有个layer（图层）属性，drawRect:方法中取得的是一个Layer Graphics Context，因此，绘制的东西其实是绘制到view的layer上去了
2）View之所以能显示东西，完全是因为它内部的layer

四、quartz 2D 绘图的代码步骤

1.获得图形上下文

CGContextRef ctx = UIGraphicsGetCurrentContext();

2.拼接路径（下面代码是搞一条线段）

//新建一个起点
void CGContextMoveToPoint(CGContextRef c, CGFloat x, CGFloat y)
//添加新的线段到某个点
void CGContextAddLineToPoint(CGContextRef c, CGFloat x, CGFloat y)
//添加一个矩形
void CGContextAddRect(CGContextRef c, CGRect rect)
//添加一个椭圆
void CGContextAddEllipseInRect(CGContextRef context, CGRect rect)
//添加一个圆弧
void CGContextAddArc(CGContextRef c, CGFloat x, CGFloat y, CGFloat radius, CGFloat startAngle, CGFloat endAngle, int
clockwise)

3.绘制路径

//Mode参数决定绘制的模式
void CGContextDrawPath(CGContextRef c, CGPathDrawingMode mode)
//绘制空心路径
void CGContextStrokePath(CGContextRef c)
//绘制实心路径
void CGContextFillPath(CGContextRef c)

提示：一般以CGContextDraw、CGContextStroke、CGContextFill开头的函数，都是用来绘制路径的

4、案例 绘制下载进度条

#import "HSProgressView.h"




@interface HSProgressView ()

@property (nonatomic,weak) UILabel *textLable;




@end




@implementation HSProgressView




- (UILabel *)textLable{

    if (nil == _textLable) {

        UILabel *tmpView = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];

        _textLable = tmpView;

        [_textLable setTextAlignment:NSTextAlignmentCenter];

        [self addSubview:_textLable];

    }

    return _textLable;

}




//重写百分比的setter方法，来做一些额外的事情




- (void)setProgressValue:(CGFloat)progressValue{

    _progressValue = progressValue;

    [self.textLable setText:[NSString stringWithFormat:@"%.2f%%",progressValue*100]];

    //绘制进度图形
    /**
     在view 上做重绘的标志，当下次屏幕刷新的时候会调用drawRect方法

     */

    [self setNeedsDisplay];//重绘视图to notify the system that your view’s contents need to be redrawn.

}




/*绘制进度*/

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect {

    // Drawing code

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGPoint center = CGPointMake(50, 50);

    CGFloat radious = 44;

    CGFloat startAngle = -M_PI_2;

    CGFloat endAngle = startAngle + self.progressValue * M_PI*2;

    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radious startAngle:startAngle endAngle:endAngle clockwise:YES];

    CGContextAddPath(context, path.CGPath);

    //渲染

    CGContextStrokePath(context);
}

五、图片水印、裁剪以及屏幕截图

1、图片水印

//1、开启一个基于位图的图形上下文
void     UIGraphicsBeginImageContextWithOptions(CGSize size, BOOL opaque, CGFloat scale)；

//2.从上下文中取得图片（UIImage）

UIImage* UIGraphicsGetImageFromCurrentImageContext();

//3.结束基于位图的图形上下文
void     UIGraphicsEndImageContext();
/*例子*/
 //1、开启上下文

    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);

    UIImage *image = [UIImage imageNamed:@"img"];

    [image drawAtPoint:CGPointZero];

    [@"@Lydia" drawAtPoint:CGPointMake(150, 150) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:12],NSForegroundColorAttributeName:[UIColor redColor]}];

    //2、获取上下文图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    //3、结束上下文

    UIGraphicsEndImageContext();

    //4、显示图片

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];

    [imageView setImage:newImage];

    [self.view addSubview:imageView];

    //5、保存图片

//    NSData *data = UIImageJPEGRepresentation(newImage, 0.0001);// value 1.0 represents the least compression (or best quality)

    NSData *data = UIImagePNGRepresentation(newImage);//将图片转换成二进制数据

    [data writeToFile:@"/Users/devzkn/Desktop/lydia.png" atomically:YES];

2、图片裁剪

void CGContextClip(CGContextRef c);//将当前上下所绘制的路径裁剪出来（超出这个裁剪区域的都不能显示）
 //方式二、裁剪感兴趣的部分

 UIRectClip(textFrame);//Modifies the current clipping path by intersecting it with the specified rectangle.
/*裁剪代码*/
#import "UIImage+Tool.h"

@implementation UIImage (Tool)

+ (UIImage *)imageWithName:(NSString *)name border:(CGFloat)border borderColor:(UIColor *)borderColor{

    UIImage *image = [UIImage imageNamed:name];//旧图片

    CGFloat borderWidth = border;//圆环高度

    //新图片的大小

    CGFloat newImageW = image.size.width+borderWidth*2;

    CGFloat newImageH = image.size.height+borderWidth*2;

    CGFloat circleW = (newImageH>newImageW) ? newImageW:newImageH;//新的图片尺寸



    //1、开启上下文

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(circleW, circleW), NO, 0.0);

    //1>画大圆正切于矩形-----------

    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, circleW,circleW)];

    //获取当前上下文

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextAddPath(context, path.CGPath);

    [borderColor set];

    CGContextFillPath(context);

    //绘制小圆

    //2>画一个正切于旧图片的小圆-----

    CGRect clipR = CGRectMake(borderWidth,borderWidth,image.size.width,image.size.height);

    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:clipR];

    [clipPath addClip];//设置裁剪区域

    [image drawAtPoint:CGPointMake(borderWidth, borderWidth)];

    //2、获取上下文图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();



    //3、结束上下文

    UIGraphicsEndImageContext();

    return newImage;   

}

3、屏幕截图

核心代码：调用某个view的layer的renderInContext:方法即可
- (void)renderInContext:(CGContextRef)ctx;

UIGraphicsBeginImageContext(self.view.bounds.size);

   CGContextRef context = UIGraphicsGetCurrentContext();

   //将layer渲染到上下文

   [self.view.layer renderInContext:context];

   //获取新图片

   UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

   NSData *data = UIImagePNGRepresentation(newImage);

   [data writeToFile:@"/Users/devzkn/Desktop/layer.png" atomically:YES];

正文

一、案例
1、饼图

/*pie

 寻找规律

 */

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect {

    // Drawing code

    CGContextRef context = UIGraphicsGetCurrentContext();

    NSArray *data = @[@25,@25,@50];

    CGPoint center = CGPointMake(125, 125);

    CGFloat radious = 100;//半径

    CGFloat startAngle = 0;//起始弧度

    CGFloat endAngle = 0;

    CGFloat angle = 0;

    //开始绘制饼图

    for (NSNumber *num in data) {

        //绘制

        angle =num.floatValue/100.0 *M_PI*2;

        startAngle = endAngle;//上一个饼图的结束弧度为下一个饼图的开始弧度

        endAngle = startAngle + angle;

        UIBezierPath *path2 = [UIBezierPath bezierPathWithArcCenter:center radius:radious startAngle:startAngle endAngle:endAngle clockwise:YES];

        [path2 addLineToPoint:center];

        CGContextAddPath(context, path2.CGPath);

        [[UIColor randomColor]set];

        //渲染第i个

        CGContextFillPath(context);

    }



}




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

    [self setNeedsDisplay];

}

//生成随机颜色
+ (UIColor *)randomColor{

    /*

     RGB 24位，RGB 每个颜色通道8位，8 的二进制255，即颜色取值是0～255

     RGBA

     */

    CGFloat red = arc4random_uniform(256)/255.0;

    CGFloat blue = arc4random_uniform(256)/255.0;

    CGFloat green = arc4random_uniform(256)/255.0;

    return  [UIColor colorWithRed:red green:green blue:blue alpha:1];

}

2、柱状图

/* bar*/

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect {

    // Drawing code

    CGContextRef context = UIGraphicsGetCurrentContext();

    NSArray *data = @[@25,@25,@50];

    CGFloat ViewH =CGRectGetHeight(self.frame);

    CGFloat width = CGRectGetWidth(self.frame)/(2*data.count-1);

    for (int i =0; i<data.count; i++) {

        //绘制

        CGFloat height = ViewH*([(NSNumber *)data[i] floatValue]/100.0);

        CGFloat x = i*width*2;

        CGFloat y = ViewH - height ;

        UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(x, y, width, height)];

        CGContextAddPath(context, path.CGPath);

        [[UIColor randomColor] set];

        //渲染

        CGContextFillPath(context);

    }  
}

3、UIKit的演练

1》- (void)drawInRect:(CGRect)rect withAttributes:(NSDictionary<NSString *,id> *)attrs

/*

 字符属性



 字符属性可以应用于 attributed string 的文本中。



 NSString *const NSFontAttributeName;(字体)



 NSString *const NSParagraphStyleAttributeName;(段落)



 NSString *const NSForegroundColorAttributeName;(字体颜色)



 NSString *const NSBackgroundColorAttributeName;(字体背景色)



 NSString *const NSLigatureAttributeName;(连字符)



 NSString *const NSKernAttributeName;(字间距)



 NSString *const NSStrikethroughStyleAttributeName;(删除线)



 NSString *const NSUnderlineStyleAttributeName;(下划线)



 NSString *const NSStrokeColorAttributeName;(边线颜色)



 NSString *const NSStrokeWidthAttributeName;(边线宽度)



 NSString *const NSShadowAttributeName;(阴影)(横竖排版)



 NSString *const NSVerticalGlyphFormAttributeName;



 常量



 1> NSFontAttributeName(字体)



 该属性所对应的值是一个 UIFont 对象。该属性用于改变一段文本的字体。如果不指定该属性，则默认为12-point Helvetica(Neue)。



 2> NSParagraphStyleAttributeName(段落)



 该属性所对应的值是一个 NSParagraphStyle 对象。该属性在一段文本上应用多个属性。如果不指定该属性，则默认为 NSParagraphStyle 的defaultParagraphStyle 方法返回的默认段落属性。



 3> NSForegroundColorAttributeName(字体颜色)



 该属性所对应的值是一个 UIColor 对象。该属性用于指定一段文本的字体颜色。如果不指定该属性，则默认为黑色。



 4> NSBackgroundColorAttributeName(字体背景色)



 该属性所对应的值是一个 UIColor 对象。该属性用于指定一段文本的背景颜色。如果不指定该属性，则默认无背景色。



 5> NSLigatureAttributeName(连字符)



 该属性所对应的值是一个 NSNumber 对象(整数)。连体字符是指某些连在一起的字符，它们采用单个的图元符号。0 表示没有连体字符。1 表示使用默认的连体字符。2表示使用所有连体符号。默认值为 1（注意，iOS 不支持值为 2）。



 6> NSKernAttributeName(字间距)



 该属性所对应的值是一个 NSNumber 对象(整数)。字母紧排指定了用于调整字距的像素点数。字母紧排的效果依赖于字体。值为 0 表示不使用字母紧排。默认值为0。



 7> NSStrikethroughStyleAttributeName(删除线)



 该属性所对应的值是一个 NSNumber 对象(整数)。该值指定是否在文字上加上删除线，该值参考“Underline Style Attributes”。默认值是NSUnderlineStyleNone。



 8> NSUnderlineStyleAttributeName(下划线)



 该属性所对应的值是一个 NSNumber 对象(整数)。该值指定是否在文字上加上下划线，该值参考“Underline Style Attributes”。默认值是NSUnderlineStyleNone。



 9> NSStrokeColorAttributeName(边线颜色)



 该属性所对应的值是一个 UIColor 对象。如果该属性不指定（默认），则等同于 NSForegroundColorAttributeName。否则，指定为删除线或下划线颜色。更多细节见“Drawing attributedstrings that are both filled and stroked”。



 10> NSStrokeWidthAttributeName(边线宽度)



 该属性所对应的值是一个 NSNumber 对象(小数)。该值改变描边宽度（相对于字体size 的百分比）。默认为 0，即不改变。正数只改变描边宽度。负数同时改变文字的描边和填充宽度。例如，对于常见的空心字，这个值通常为3.0。



 11> NSShadowAttributeName(阴影)
 该属性所对应的值是一个 NSShadow 对象。默认为 nil。
 12> NSVerticalGlyphFormAttributeName(横竖排版)
 该属性所对应的值是一个 NSNumber 对象(整数)。0 表示横排文本。1 表示竖排文本。在 iOS 中，总是使用横排文本，0 以外的值都未定义。
 */

4、雪花

- (void)drawRect:(CGRect)rect{

    if (self.snowY >= CGRectGetHeight(self.frame)) {

        self.snowY = 0;

    }

    self.snowY++;

    UIImage *image = [UIImage imageNamed:@"雪花"];

    [image drawAtPoint:CGPointMake(0, self.snowY)];

}




- (void)awakeFromNib{

    /*

     1.NSTimer的精确度就显得低了点，比如NSTimer的触发时间到的时候，runloop如果在阻塞状态，触发时间就会推迟到下一个runloop周期－－》导致任务的叠加。

     2.CADisplayLink使用场合相对专一，适合做UI的不停重绘，比如自定义动画引擎或者视频播放的渲染。NSTimer的使用范围要广泛的多，各种需要单次或者循环定时处理的任务都可以使用。在UI相关的动画或者显示内容使用 CADisplayLink比起用NSTimer的好处就是我们不需要在格外关心屏幕的刷新频率了，因为它本身就是跟屏幕刷新同步的。

     */

//    [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(setNeedsDisplay) userInfo:nil repeats:YES];

    /*

     IOS设备的屏幕刷新频率是固定的，CADisplayLink在正常情况下会在每次刷新结束都被调用，精确度相当高。

     */

    CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(setNeedsDisplay)];

    [link addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];

}

5、矩阵操作

- (void)drawRect:(CGRect)rect{

    CGContextRef context = UIGraphicsGetCurrentContext();

    //平移上下文

    CGContextTranslateCTM(context, 50, 100);

    CGContextRotateCTM(context, M_PI_4);

    CGContextScaleCTM(context, 0.2, 0.7);

    //上下文矩阵操作，之后在设置绘图信息（路径）

    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(-50, -100, 120, 100)];

    CGContextAddPath(context, path.CGPath);

    [[UIColor yellowColor]set];

    CGContextStrokePath(context);

}

6、手势密码

//

//  HSLockView.m

//  20140621-手势解锁

//

//  Created by devzkn on 4/21/16.

//  Copyright © 2016 hisun. All rights reserved.

//




#import "HSLockView.h"




@interface HSLockView ()

@property (nonatomic,strong) NSMutableArray *btns;//存储选中按钮

@property (nonatomic,assign) CGPoint pos;//当前手指的位置










@end

@implementation HSLockView

- (NSMutableArray *)btns{

    if (nil == _btns) {

        _btns = [NSMutableArray array];

    }

    return _btns;

}




#if 0

- (void)awakeFromNib{

    //绘制九宫格

}

#endif




- (instancetype)initWithCoder:(NSCoder *)aDecoder{



    self = [super initWithCoder:aDecoder];

    if (self) {

        //绘制九宫格按钮

        [self addBtns];

    }

    return self;



}




/**

 绘制九宫格

 */

- (void)addBtns{

    UIImage *normalImage = [UIImage imageNamed:@"gesture_node_normal"];

    UIImage *highlightedImage = [UIImage imageNamed:@"gesture_node_highlighted"];




    for (int i=0; i<9; i++) {

        //绘制按钮

        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];

        //设置共性信息

        [btn setTag:i];//用于标记按钮

        [btn setImage:normalImage forState:UIControlStateNormal];

        [btn setImage:highlightedImage forState:UIControlStateSelected];//选中状态要手动管理

        /**

         处理按钮点击事件：

         方式一：addTarget:self

         方式二；touches ，设置按钮为不可交互，交给VIew进行处理(事件的传递原理)

         */

        //添加监听方法，进行性手动管理选中状态

//        [btn addTarget:self action:@selector(clickBtn:) forControlEvents:UIControlEventTouchDown];

        [btn setUserInteractionEnabled:NO];




        [self addSubview:btn];

    }

}




#pragma  mark - 点击事件

#if 0

- (void)clickBtn:(UIButton*)btn{

    [btn setSelected:YES];

}

#endif




#pragma  mark - 使用touches方法 进行按钮的选中处理




/** 获取当前触摸点的坐标*/

- (CGPoint) getPosWithTouches:(NSSet *)touches{

    if (touches == nil) {

        return CGPointZero;

    }

    UITouch *touch = [touches anyObject];//Returns one of the objects in the set, or nil if the set contains no objects.

    return [touch locationInView:self];//当前触摸点

}




/** 选中按钮的获取*/

- (UIButton *) getButtonWithPos:(CGPoint)pos{

    //计算选中范围

    CGRect selectRect;

    UIButton *posBtn ;

    CGFloat wh =30;

    for (UIButton *btn in self.subviews) {

        CGFloat x = btn.center.x-wh*0.5;

        CGFloat y = btn.center.y- wh *0.5;

        selectRect = CGRectMake(x, y, wh, wh);

        BOOL flg = CGRectContainsPoint(selectRect, pos);

        if (flg) {

             posBtn = btn;

            break;

        }

    }

    return posBtn;

}




#pragma mark - 手指抬起的处理

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    //判断是否解锁成功

    NSMutableString *answerStr = [[NSMutableString alloc]init];

    for (UIButton *btn in self.btns) {

        [answerStr appendFormat:@"%d",btn.tag];

    }

    NSLog(@"%@",answerStr);

    //去除选中状态

    [self.btns makeObjectsPerformSelector:@selector(setSelected:) withObject:NO];

    //清空轨迹

    [self.btns removeAllObjects];

    [self setNeedsDisplay];

}




/**控制按钮的选择状态 */

#if 0

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



}

#endif




/** 存储选中按钮*/

- (void) touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    CGPoint pos = [self getPosWithTouches:touches];

    [self setPos:pos];

    UIButton *btn = [self getButtonWithPos:pos];

    if (btn && btn.selected == NO) {

        [btn setSelected:YES];

        if (![self.btns containsObject:btn]) {

            [self.btns addObject:btn];//存储选中按钮

        }

    }

    [self setNeedsDisplay];//绘制




}










#pragma mark - 画线




- (void)drawRect:(CGRect)rect{

    if (self.btns.count == 0) {

        return;

    }

    //开始绘制

    UIBezierPath *path = [UIBezierPath bezierPath];

    for (int i=0; i<self.btns.count; i++) {

        UIButton *btn = self.btns[i];

        if (i==0) {

            [path moveToPoint:btn.center];

        }else{

            [path addLineToPoint:btn.center];

        }

    }



    [path addLineToPoint:self.pos];

    //设置绘图状态

    [[UIColor greenColor]set];

    [path  setLineWidth:10];

    [path setLineCapStyle:kCGLineCapRound];

    [path  setLineJoinStyle:kCGLineJoinRound];



    [path stroke];

}










#pragma mark - layoutSubviews 设置子视图的位置信息




- (void)layoutSubviews{

    [super layoutSubviews];

    //设置位置信息

    CGFloat btnWidth = 74;

    CGFloat btnHeight = 74;

    CGFloat x = 0;

    CGFloat y = 0;

    int col = 0;//所在的列数

    int row = 0;//所在的行数

    int tolCol = 3;//总列数

    CGFloat viewWidth = CGRectGetWidth(self.frame);

    CGFloat viewHeight = CGRectGetHeight(self.frame);

    CGFloat rowMargin = (viewWidth - tolCol*btnWidth)*0.25;//间距

    CGFloat colMargin = (viewHeight - tolCol*btnHeight)*0.25;//间距




    for (int i =0; i<9; i++) {

        //绘制

        UIButton *btn = self.subviews[i];

        //计算所在的列数

        col = i % tolCol;

        row = i / tolCol;//所在行数

        x = col*(rowMargin+btnWidth)+rowMargin;//x 与所在的列相关

        y = row*(colMargin+btnHeight)+colMargin;

        [btn setFrame:CGRectMake(x, y, btnWidth, btnHeight)];
    }
}
@end

7、画板

1》从相册选择照片
从相册选择照片 Expand source

//
//  ViewController.m
//  20160421-画板
//
//  Created by devzkn on 4/21/16.
//  Copyright © 2016 hisun. All rights reserved.
//

#import "ViewController.h"
#import "HSPaintView.h"
#import "HSHandleImageView.h"


@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate>
@property (weak, nonatomic) IBOutlet HSPaintView *paintView;

@end

@implementation ViewController
- (IBAction)lineWidthValueChange:(UISlider *)sender {
    [self.paintView setLineWidth:sender.value];
}
- (IBAction)colorClick:(UIButton *)sender {
    [self.paintView setColor:sender.backgroundColor];

}
#pragma mark - 清屏
- (IBAction)cleanScreen:(UIBarButtonItem *)sender {
    [self.paintView cleanScreen];

}
- (IBAction)undo:(UIBarButtonItem *)sender {
    [self.paintView undo];
}
- (IBAction)eraserClick:(UIBarButtonItem *)sender {
    [self.paintView setColor:[UIColor whiteColor]];
}
#pragma mark - 从相册选择照片
- (IBAction)selectedPicture:(UIBarButtonItem*)sender {
    //去用户相册
    UIImagePickerController *pickerVc = [[UIImagePickerController alloc]init];
    /*
     UIImagePickerControllerSourceTypePhotoLibrary,相簿，默认值
     UIImagePickerControllerSourceTypeCamera,//真机测试
     UIImagePickerControllerSourceTypeSavedPhotosAlbum
     */
    [pickerVc setSourceType:UIImagePickerControllerSourceTypeSavedPhotosAlbum];//照片
    //modal
    //设置代理
    [pickerVc setDelegate:self];
    [self presentViewController:pickerVc animated:YES completion:^{
        //
    }];

}
#pragma mark - UIImagePickerControllerDelegate
// The picker does not dismiss itself; the client dismisses it in these callbacks.
// The delegate will receive one or the other, but not both, depending whether the user
// confirms or cancels.
#if 0
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo{// NS_DEPRECATED_IOS(2_0, 3_0)
    NSLog(@"%s",__func__);
}
#endif
/**
 选中图片的时候调用
 */
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    /**
     {
     UIImagePickerControllerMediaType = "public.image";
     UIImagePickerControllerOriginalImage = "<UIImage: 0x7ae83b30> size {3000, 2002} orientation 0 scale 1.000000";
     UIImagePickerControllerReferenceURL = "assets-library://asset/asset.JPG?id=ED7AC36B-A150-4C38-BB8C-B6D696F4F2ED&ext=JPG";
     }
     */
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
    HSHandleImageView *handleView = [[HSHandleImageView alloc]initWithFrame:self.paintView.frame];
    /*
     回调，进行传值,定义block的具体内容
     */
    [handleView setBlock:^(UIImage *image){
        [self.paintView setImage:image];
    }];
    [handleView setImage:image];//将选中的图片显示到handleView
    [self.view addSubview:handleView];
    [self dismissViewControllerAnimated:YES completion:^{
        //
    }];

}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    NSLog(@"%s",__func__);
    [self dismissViewControllerAnimated:YES completion:^{
        //
    }];
}

#pragma mark 保存图片
- (IBAction)save:(UIBarButtonItem *)sender {
    [self.paintView save];

}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

@end

2》画板的基本功能
画板的辅助功能

//

//  HSPaintView.m

//  20160421-画板

//

//  Created by devzkn on 4/21/16.

//  Copyright © 2016 hisun. All rights reserved.

//




#import "HSPaintView.h"

#import "HSPaintPath.h"

#import "MBProgressHUD+MJ.h"




@interface HSPaintView ()

@property (nonatomic,strong) HSPaintPath *path;//存储当前触摸的路径

@property (nonatomic,strong) NSMutableArray *paths;//存储历史的路径







@end




@implementation HSPaintView




- (void)setImage:(UIImage *)image{

    _image = image;

    [self.paths addObject:image];

    [self setNeedsDisplay];



}




- (void)cleanScreen{

    [self.paths removeAllObjects];

    [self setNeedsDisplay];



}

- (void)undo{

    [self.paths removeLastObject];

    [self setNeedsDisplay];



}




- (void)setLineWidth:(CGFloat)lineWidth{

    _lineWidth = lineWidth;

}




- (void) setColor:(UIColor *)color{

    _color = color;

}




- (NSMutableArray *)paths{

    if (nil == _paths) {

        _paths = [NSMutableArray array];

    }

    return _paths;

}




/**     获取触摸点*/

- (CGPoint) pointWithTouches:(NSSet *)touches{

    UITouch *touch = [touches anyObject];

    return [touch locationInView:self];

}

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

    self.path = [HSPaintPath pathWithColor:self.color lineWidht:self.lineWidth startPoint:[self pointWithTouches:touches]];

    [self.paths addObject:self.path];

}

-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    //确定终点

    [self.path addLineToPoint:[self pointWithTouches:touches]];

    [self setNeedsDisplay];

}

#pragma mark - 绘制状态

- (void)drawRect:(CGRect)rect{

    if (!self.paths.count) {

        return;

    }

    for (HSPaintPath *path in self.paths) {

        if ([path  isKindOfClass:[UIImage class]]) {

            //画图片

            UIImage *image = (UIImage *)path;

            [image drawAtPoint:CGPointZero];

        }else{

            //设置绘制状态

            [path.color set];

            //描边

            [path stroke];

        }

    }

}




#pragma mark -初始化绘制状态

- (void)awakeFromNib{

    self.lineWidth = 2;

}




#pragma mark - 保存到用户相册

- (void)save{

    //1.截屏

    UIGraphicsBeginImageContext(self.bounds.size);

    //渲染

    //获取上下文

    CGContextRef context = UIGraphicsGetCurrentContext();

    [self.layer renderInContext:context];

    //2.获取新图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    //3.关闭

    UIGraphicsEndImageContext();

    //4\保存

//        NSData *data = UIImagePNGRepresentation(newImage);

//        [data writeToFile:@"/Users/devzkn/Desktop/layer.png" atomically:YES];

    //保存到用户相册里面

    UIImageWriteToSavedPhotosAlbum(newImage, self, @selector(image:didFinishSavingWithError:contextInfo:), context);   

}




- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{

    NSLog(@"%s",__func__);

    if (error) {

        //保存失败

        [MBProgressHUD showError:@"保存失败"];




    }else{

        [MBProgressHUD showSuccess:@"保存成功"];

    }

}

3》手势识别器的处理
手势识别器的使用

#if 1

- (instancetype)initWithFrame:(CGRect)frame{

    self = [super initWithFrame:frame];

    if (self) {

        //设置自己的属性

        [self addUILongPressGestureRecognizer];

        [self addUIRotationGestureRecognizer];

        [self addUIPinchGestureRecognizer];



    }

    return self;

}

#endif




#pragma mark - 添加手势识别器

- (void) addUILongPressGestureRecognizer{

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];

    [longPress setDelegate:self];

    [self.imageView addGestureRecognizer:longPress];

}




- (void) addUIRotationGestureRecognizer{

    UIRotationGestureRecognizer *rotationGR = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotationGR:)];

    [rotationGR setDelegate:self];

    [self.imageView addGestureRecognizer:rotationGR];

}




#pragma mark - rotation

- (void) rotationGR:(UIRotationGestureRecognizer*)rotationGR{

    NSLog(@"%s",__func__);

    [self.imageView setTransform:CGAffineTransformRotate(self.imageView.transform, rotationGR.rotation)];

    [rotationGR setRotation:0];



}




- (void) addUIPinchGestureRecognizer{

    UIPinchGestureRecognizer *pinchGR = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinchGR:)];

    [pinchGR setDelegate:self];

    [self.imageView addGestureRecognizer:pinchGR];}







- (void) pinchGR:(UIPinchGestureRecognizer*)pinchGR{

    NSLog(@"%s",__func__);

    [self.imageView setTransform:CGAffineTransformScale(self.imageView.transform, pinchGR.scale, pinchGR.scale)];

    [pinchGR setScale:1];





}




#pragma mark - 长按处理

- (void) longPress:(UILongPressGestureRecognizer*)longPressGR{

    if (longPressGR.state == UIGestureRecognizerStateEnded) {

        //动画

        [UIView animateWithDuration:0.5 animations:^{

            //设置透明度

            [self.imageView setAlpha:0.3];

        } completion:^(BOOL finished) {

            //还原透明度

            [UIView animateWithDuration:0.5 animations:^{

                [self.imageView setAlpha:1.0];

            }completion:^(BOOL finished) {

                //1、截屏

                UIGraphicsBeginImageContext(self.bounds.size);

                [self.layer renderInContext:UIGraphicsGetCurrentContext()];

                UIImage *newImage =UIGraphicsGetImageFromCurrentImageContext();

                UIGraphicsEndImageContext();

                //2.将图片传递给VC，进行渲染--使用block

                self.block(newImage);

                //3销毁自己

                [self removeFromSuperview];

            }];

        }];



    }

}




- (void)setImage:(UIImage *)image{

    _image = image;

    [self.imageView setImage:image];

}

#pragma mark - gestureRecognizerDelegate

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{

    return YES;

}

总结

一、编程规范
1、枚举类型变量通常以K开头
枚举定义 Expand source

/* Line cap styles. */

typedef CF_ENUM(int32_t, CGLineCap) {
    kCGLineCapButt,

    kCGLineCapRound,

    kCGLineCapSquare
};

二、语法
1、字符串格式
1》转义符号％

[self.textLable setText:[NSString stringWithFormat:@"%.2f%%",progressValue*100]];