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主控制器的关键代码:
一 ViewController.m
#import "ViewController.h" #import "ZRPaintView.h" #import "UIImage+ZR.h" @interface ViewController () - (IBAction)clear; - (IBAction)back; - (IBAction)save; @property (weak, nonatomic) IBOutlet ZRPaintView *paintView; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } - (IBAction)clear { [self.paintView clear]; } - (IBAction)back { [self.paintView back]; } - (IBAction)save { //1 截图 UIImage *image = [UIImage captureWithView:self.paintView]; //2 保存到图片 UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil); } /** * 保存图片操作之后就会调用 * * @param image image * @param error error */ - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{ if (error) { NSLog(@"保存失败"); }else{ NSLog(@"保存成功"); } } @end
二 创建一个继承自UIView的子类:
ZRPaintView.h
#import <UIKit/UIKit.h> @interface ZRPaintView : UIView -(void)clear; -(void)back; @end
ZRPaintView.m
#import "ZRPaintView.h" @interface ZRPaintView () @property(nonatomic,strong) NSMutableArray *totalPathPoints; //用来记录 @property(nonatomic,strong) NSMutableArray *pathPoints; @end @implementation ZRPaintView -(NSMutableArray *)totalPathPoints{ if (!_pathPoints) { _pathPoints = [NSMutableArray array]; } return _pathPoints; } -(void)clear{ [self.totalPathPoints removeAllObjects]; [self setNeedsDisplay]; } -(void)back{ [self.totalPathPoints removeLastObject]; [self setNeedsDisplay]; } /** * 确定起点 */ -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ UITouch *touch = [touches anyObject]; CGPoint startPos = [touch locationInView:touch.view]; //每一次开始触摸,就新建一个数组来存放这一次触摸过程中所有点(这次触摸过程中得所有点) NSMutableArray *pathPoints = [NSMutableArray array]; [pathPoints addObject:[NSValue valueWithCGPoint:startPos]]; [self.totalPathPoints addObject:pathPoints]; //添加这个路径中得所有点到数组中 [self setNeedsDisplay]; } /** * 连线 */ -(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ UITouch *touch = [touches anyObject]; CGPoint currentPos = [touch locationInView:touch.view]; //取出这次路径对应的数组 NSMutableArray *pathPoints = [self.totalPathPoints lastObject]; [pathPoints addObject:[NSValue valueWithCGPoint:currentPos]]; [self setNeedsDisplay]; } /** * 连线 */ -(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ // UITouch *touch = [touches anyObject]; // CGPoint endPos = [touch locationInView:touch.view]; // // //取出这次路径对应的数组 // NSMutableArray *pathPoints = [self.totalPathPoints lastObject]; // [pathPoints addObject:[NSValue valueWithCGPoint:endPos]]; // // [self setNeedsDisplay]; [self touchesMoved:touches withEvent:event]; } - (void)drawRect:(CGRect)rect { // UIRectFill(CGRectMake(0, 0, 100, 100)); CGContextRef ctx = UIGraphicsGetCurrentContext(); for (NSMutableArray *pathPoints in self.totalPathPoints) { for (int i = 0; i<pathPoints.count; i++) {//一条路径 CGPoint pos = [pathPoints[i] CGPointValue]; if (i==0) { CGContextMoveToPoint(ctx, pos.x, pos.y); }else{ CGContextAddLineToPoint(ctx, pos.x, pos.y); } } } CGContextSetLineCap(ctx, kCGLineCapRound); CGContextSetLineJoin(ctx, kCGLineJoinRound); CGContextSetLineWidth(ctx, 5); CGContextStrokePath(ctx); } @end
三 创建UIImage分类文件:
UIImage+ZR.h
#import <UIKit/UIKit.h> @interface UIImage (ZR) +(instancetype)captureWithView:(UIView *)view; @end
UIImage+ZR.m
#import "UIImage+ZR.h" @implementation UIImage (ZR) +(instancetype)captureWithView:(UIView *)view{ //1 开启上下文 UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 0.0); //2 将控制器view的layer渲染到上下文 [view.layer renderInContext:UIGraphicsGetCurrentContext()]; //3 取出图片 UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); //4 结束上下文 UIGraphicsEndImageContext(); return newImage; } @end
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原文地址:http://www.cnblogs.com/xuanzhangran123/p/5154121.html