iOS 手势绘图/小画板的实现-白红宇

iOS 手势绘图/小画板的实现

阅读量：4290 次

发布时间：2019-05-27

本文共 3745 字，大约阅读时间需要 12 分钟。

#import "ViewController.h"#import "CZPaintView.h"@interface ViewController ()@property (weak, nonatomic) IBOutlet UISlider *slider;@property (weak, nonatomic) IBOutlet CZPaintView *paintView;@end@implementation ViewController//滑动slider事件- (IBAction)sliderValueChanged:(id)sender{    //设置线宽    self.paintView.lineWidth = self.slider.value;}//点击按钮 传入按钮颜色- (IBAction)colorBtnClick:(UIButton *)sender{    //设置线的颜色    self.paintView.lineColor = sender.backgroundColor;}//清屏- (IBAction)clear:(id)sender {    [self.paintView clear];}//回退- (IBAction)back:(id)sender {    [self.paintView back];}//橡皮擦- (IBAction)eraser:(id)sender {    [self.paintView eraser];}//保存- (IBAction)save:(id)sender{    //1.开启一个图形上下文对象    UIGraphicsBeginImageContextWithOptions(self.paintView.frame.size, NO, 0.0);        //2.获取刚刚开启的图形上下文对象    CGContextRef ctx = UIGraphicsGetCurrentContext();        //3.通过view.layer的renderInContext的方法 把指定view的内容绘制到图形上下文中    [self.paintView.layer renderInContext:ctx];        //4.从图形上下文中获取图片    UIImage * getImage = UIGraphicsGetImageFromCurrentImageContext();        //5.结束图形上下文    UIGraphicsEndImageContext();        //6.保存图片    UIImageWriteToSavedPhotosAlbum(getImage, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);    }- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;{    NSString * str = @"保存成功";    if(error)    {        str = @"保存失败";    }    NSLog(@"%@",str);}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.        //设置默认线宽    self.paintView.lineWidth = self.slider.value;}//隐藏状态栏- (BOOL) prefersStatusBarHidden{    return YES;}

#import 
   
    @interface CZPaintView : UIView@property(nonatomic,assign)CGFloat lineWidth;@property (nonatomic, strong) UIColor *lineColor;//清屏- (void)clear;//回退- (void) back;//橡皮擦- (void) eraser;@end

#import "CZPaintView.h"#import "CZBezierPath.h"@interface CZPaintView()//@property (nonatomic, strong) UIBezierPath * path;@property (nonatomic, strong) NSMutableArray *paths;@end@implementation CZPaintView//懒加载- (NSMutableArray *)paths{    if(_paths == nil)    {        _paths = [NSMutableArray array];    }    return _paths;}//实现清屏方法- (void)clear{    //删除数组中的路径    [self.paths removeAllObjects];    //执行重绘    [self setNeedsDisplay];}//实现回退方法- (void)back{    //删除数组中的最后一个路径    [self.paths removeLastObject];        //执行重绘    [self setNeedsDisplay];    }//实现橡皮擦功能- (void)eraser{    //设置线的颜色    self.lineColor = self.backgroundColor;}//手指按下- (void)touchesBegan:(NSSet
   
     *)touches withEvent:(UIEvent *)event{    //1.获取触摸对象    UITouch * touch = touches.anyObject;        //2.获取触摸点    CGPoint locP = [touch locationInView:touch.view];        //3.创建绘图路径    CZBezierPath * path = [[CZBezierPath alloc] init];        //3.1设置线宽    path.lineWidth = self.lineWidth;        //3.2设置颜色    path.lineColor = self.lineColor;        //4.添加子路径    [path moveToPoint:locP];        //5.把path添加到数组中    [self.paths addObject:path];    }//手指移动- (void)touchesMoved:(NSSet
    
      *)touches withEvent:(UIEvent *)event{    //1.获取触摸对象    UITouch * touch = touches.anyObject;        //2.获取触摸点    CGPoint locP = [touch locationInView:touch.view];        //3.添加子路径    [[self.paths lastObject] addLineToPoint:locP];        //执行重绘    [self setNeedsDisplay];    }//手指抬起-(void)touchesEnded:(NSSet
     
       *)touches withEvent:(UIEvent *)event{}- (void)drawRect:(CGRect)rect {    // Drawing code    //绘图    for (CZBezierPath * path in self.paths)    {        //设置颜色        [path.lineColor set];                //设置线头样式        path.lineCapStyle = kCGLineCapRound;                //设置连接处的样式        path.lineJoinStyle = kCGLineJoinRound;                [path stroke];    }}@end