IOS drawing, screenshot and clear, ios drawing

IOS drawing, and clearing, ios drawing

1 # import "ViewController. h "2 # import" SecondVC. h "3 4 5 # define WIDTH [UIScreen mainScreen]. bounds. size. width 6 # define HEIGHT [UIScreen mainScreen]. bounds. size. height 7 8 @ interface ViewController () 9 {10 UIImageView * _ canvasView; // canvas 11 CGPoint _ startPoint; // record start coordinate 12 13} 14 @ end15 16 @ implementation ViewController17 18-(void) viewDidLoad {19 [super viewDidLoad]; 20 21 _ canvasView = [[UIImageView alloc] initWithFrame: self. view. bounds]; 22 [self. view addSubview: _ canvasView]; 23 24 UIButton * clearBtn = [UIButton buttonWithType: UIButtonTypeCustom]; 25 clearBtn. frame = CGRectMake (50, 20,100, 30); 26 [clearBtn addTarget: self action: @ selector (clearBtnClick) forControlEvents: UIControlEventTouchUpInside]; 27 [clearBtn setTitle: @ "clear" forState: UIControlStateNormal]; 28 clearBtn. backgroundColor = [UIColor orangeColor]; 29 [self. view addSubview: clearBtn]; 30 31 UIButton * cutPicBtn = [UIButton buttonWithType: UIButtonTypeCustom]; 32 cutPicBtn. frame = CGRectMake (250, 20,100, 30); 33 [cutPicBtn addTarget: self action: @ selector (cutPicBtnClick) forControlEvents: UIControlEventTouchUpInside]; 34 [cutPicBtn setTitle: @ "" forState: UIControlStateNormal]; 35 cutPicBtn. backgroundColor = [UIColor orangeColor]; 36 [self. view addSubview: cutPicBtn]; 37 38} 39 40 41-(void) touchesBegan :( NSSet <UITouch *> *) touches withEvent :( UIEvent *) event42 {43 _ startPoint = [[touches anyObject] locationInView: _ canvasView]; 44 45} 46 47-(void) touchesMoved :( NSSet <UITouch *> *) touches withEvent :( UIEvent *) event48 {49 CGPoint movePoint = [[touches anyObject] locationInView: _ canvasView]; 50 51 // There are many moving points, 52 @ autoreleasepool {53 UIGraphicsBeginImageContext (CGSizeMake (WIDTH, HEIGHT); // start the drawing of an image 54 55 [_ canvasView drawRect: _ canvasView. frame]; // draw the existing line 56 57 CGContextRef context = UIGraphicsGetCurrentContext (); // In the drawing cache, the current image is 58 CGContextSetLineWidth (context, 5 ); 59 CGContextSetRGBStrokeColor (context, 1, 0, 0, 1); 60 CGContextSetLineCap (context, kCGLineCapRound); // edge Cap 61 CGContextSetLineJoin (context, kCGLineJoinRound ); // stitch 62 63 CGContextMoveToPoint (context, _ startPoint. x, _ startPoint. y); 64 CGContextAddLineToPoint (context, movePoint. x, movePoint. y); 65 CGContextStrokePath (context); 66 _ canvasView. image = UIGraphicsGetImageFromCurrentImageContext (); // retrieve the image 67 68 UIGraphicsEndImageContext () in the current image painting area; // close the image painting 69} 70 71 _ startPoint = movePoint; 72} 73 74 75 # pragma mark-Clear button 76-(void) clearBtnClick77 {78 79 _ canvasView. image = nil; 80 81} 82 83 # pragma mark-cut button 84-(void) cutPicBtnClick85 {86 UIGraphicsBeginImageContext (CGSizeMake (WIDTH, HEIGHT )); // start drawing an image. 87 // 88 [self. view drawViewHierarchyInRect: self. view. frame afterScreenUpdates: YES]; 89 90 UIImage * image = UIGraphicsGetImageFromCurrentImageContext (); // obtain the image 91 92 UIGraphicsEndImageContext () in the current image painting area (); 93 94 SecondVC * vc = [[SecondVC alloc] init]; 95 vc. image = image; 96 [self presentViewController: vc animated: YES completion: nil]; 97}