iOS简单画板开发案例分享

#import <UIKit/UIKit.h> @interface DrawView : UIView/** 线宽 */@property (nonatomic, assign) NSInteger lineWidth; /** 颜色 */@property(nonatomic, strong) UIColor *pathColor; /** 图片 */@property(nonatomic, strong) UIImage *image; - (void)clear; - (void)undo;

- (void)awakeFromNib {     [self setUp];   } - (instancetype)initWithFrame:(CGRect)frame {     if (self == [super initWithFrame:frame]) {    [self setUp];  }  return self;}

//自定义初始化方法- (void)setUp {     //添加手势  UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];  [self addGestureRecognizer:pan];     //初始化时设置路径线宽  _lineWidth = 2;   }

#import <UIKit/UIKit.h> @interface DrawPath : UIBezierPath @property (nonatomic, strong) UIColor *pathColor; @end

@interface DrawView () @property(nonatomic, strong)DrawPath *path;/** 保存所有路径的数组 */@property(nonatomic, strong) NSMutableArray *pathArr; @end //懒加载- (NSMutableArray *)pathArr {  if (_pathArr == nil) {         _pathArr = [NSMutableArray array];       }  return _pathArr;}

- (void)pan:(UIPanGestureRecognizer *)pan {     //获取开始的触摸点  CGPoint startP = [pan locationInView:self];     if (pan.state == UIGestureRecognizerStateBegan) {         //创建贝塞尔路径    _path = [[DrawPath alloc]init];    _path.lineWidth = _lineWidth;    _path.pathColor = _pathColor;         //不能在手指抬起时将路径添加到数组，因为在遍历数组画线时路径还没有被添加到数组里面    [_pathArr addObject:_path];         //设置起点    [_path moveToPoint:startP];       }     //连线  [_path addLineToPoint:startP];     //重绘，调用drawRect方法  [self setNeedsDisplay];   }

- (void)drawRect:(CGRect)rect {     //把所有路径画出来  for (DrawPath *path in self.pathArr) {         if ([path isKindOfClass:[UIImage class]]) {      //画图      UIImage *image = (UIImage *)path;      [image drawInRect:rect];    }else {      //画线      [path.pathColor set];      [path stroke];    }  }   }

- (void)setImage:(UIImage *)image {     _image = image;     [self.pathArr addObject:image];     //重绘调用drawRect才能在画板上显示图片  [self setNeedsDisplay];}

- (void)clear {  //清除  [self.pathArr removeAllObjects];     [self setNeedsDisplay];   } - (void)undo {  //撤销  [self.pathArr removeLastObject];     [self setNeedsDisplay];}

@interface ViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>@property (weak, nonatomic) IBOutlet DrawView *drawView;@end

- (IBAction)clear:(id)sender {     //清屏  [_drawView clear];   } - (IBAction)undo:(id)sender {     //撤销  [_drawView undo];   } - (IBAction)eraser:(id)sender {     //擦除 就是把路径的颜色设置为画板的背景色，假象  _drawView.pathColor = _drawView.backgroundColor;  _drawView.lineWidth = 20;   } - (IBAction)changeLineWidth:(UISlider *)sender {     //改变路径线宽  _drawView.lineWidth = sender.value;   } - (IBAction)changeColor:(UIButton *)sender {        //改变路径颜色  _drawView.pathColor = sender.backgroundColor;   } - (IBAction)pickPhoto:(id)sender {     //选择照片  //弹出系统相册  UIImagePickerController *picker = [[UIImagePickerController alloc]init];     //设置选择控制器的来源 UIImagePickerControllerSourceTypeSavedPhotosAlbum:照片库  picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;     //设置代理  picker.delegate = self;     //modal出控制器  [self presentViewController:picker animated:YES completion:nil];   } - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {     //获取选择的图片  UIImage *image = info[UIImagePickerControllerOriginalImage];     //创建一个处理图片的view  ImageHandleView *handleView = [[ImageHandleView alloc]initWithFrame:self.drawView.bounds];     handleView.handleCompletionBlock = ^(UIImage *image){         _drawView.image = image;  };     [self.drawView addSubview:handleView];     //将图片画在画板上  handleView.image = image;     //_drawView.image = image;     //dismiss  [self dismissViewControllerAnimated:YES completion:nil];  //NSLog(@"%@", info);   } - (IBAction)save:(id)sender {     [UIView animateWithDuration:0.15 animations:^{    //保存当前画板上的内容         //开启上下文    UIGraphicsBeginImageContextWithOptions(_drawView.bounds.size, NO, 0);         //获取位图上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();         //把控件上的图层渲染到上下文    [_drawView.layer renderInContext:ctx];         //获取上下文中的图片    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();         //关闭上下文    UIGraphicsEndImageContext();         //保存图片到相册    UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);         self.drawView.alpha = 0;  } completion:^(BOOL finished) {    [UIView animateWithDuration:0.15 animations:^{      self.drawView.alpha = 1;    }];  }];   } //保存成功后的方法必须是这个，不能随便写- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {     NSLog(@"保存成功");   }

#import <UIKit/UIKit.h> @interface ImageHandleView : UIView/** 图片 */@property(nonatomic, strong) UIImage *image; /** block */@property(nonatomic, strong) void(^handleCompletionBlock)(UIImage *image);@end

#import "ImageHandleView.h" @interface ImageHandleView () <UIGestureRecognizerDelegate> /** image */@property(nonatomic, weak) UIImageView *imageView; @end @implementation ImageHandleView //防止图片上的触摸事件传递到画板- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {     return _imageView;} - (UIImageView *)imageView {     if (_imageView == nil) {    UIImageView *imageV = [[UIImageView alloc]initWithFrame:self.bounds];         _imageView = imageV;         //设置imgaeview允许与用户交互    _imageView.userInteractionEnabled = YES;         //添加手势    [self setUpGestureRecognizer];         //把这个imageview添加到图片处理的view上    [self addSubview:imageV];       }  return _imageView;} #pragma mark - 添加手势- (void)setUpGestureRecognizer {     //平移手势  UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];  [_imageView addGestureRecognizer:pan];     //旋转手势  UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotation:)];  rotation.delegate = self;  [_imageView addGestureRecognizer:rotation];     //缩放手势  UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinch:)];  pinch.delegate = self;  [_imageView addGestureRecognizer:pinch];     //长按手势  UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];  [_imageView addGestureRecognizer:longPress];   } #pragma mark - 处理平移手势- (void)pan:(UIPanGestureRecognizer *)pan {     //获取手指的偏移量  CGPoint tranp = [pan translationInView:self.imageView];     //设置imageview的形变  self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, tranp.x, tranp.y);     //复位  [pan setTranslation:CGPointZero inView:self.imageView];   } #pragma mark - 处理旋转手势- (void)rotation:(UIRotationGestureRecognizer *)rotation {     //设置imageview的形变  self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotation.rotation);     //复位  rotation.rotation = 0;   } #pragma mark - 处理缩放手势- (void)pinch:(UIPinchGestureRecognizer *)pinch {     //设置imageview的形变  self.imageView.transform = CGAffineTransformScale(self.imageView.transform, pinch.scale, pinch.scale);     //复位  pinch.scale = 1;   } #pragma mark - 处理长按手势- (void)longPress:(UILongPressGestureRecognizer *)longPress {     //图片处理完成  if (longPress.state == UIGestureRecognizerStateBegan) {         //高亮效果    [UIView animateWithDuration:0.25 animations:^{      self.imageView.alpha = 0;    } completion:^(BOOL finished) {            [UIView animateWithDuration:0.25 animations:^{        self.imageView.alpha = 1;      } completion:^(BOOL finished) {                 //高亮时生成一张新的图片        //开启位图上下文        UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0);                 //获取位图上下文        CGContextRef ctx = UIGraphicsGetCurrentContext();                 //把控件的图层渲染到上下文        [self.layer renderInContext:ctx];                 //从上下文中获取新的图片        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();                 //关闭上下文        UIGraphicsEndImageContext();                 //调用block        if(_handleCompletionBlock) {          _handleCompletionBlock(image);        }                 //移除父控件        [self removeFromSuperview];               }];           }];            }   } #pragma mark - 手势代理方法 <UIGestureRecognizerDelegate>- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {     //yes表示同时支持多个手势  return YES;   } - (void)setImage:(UIImage *)image {     _image = image;     //把图片展示到UIImageView上  self.imageView.image = image; } @end