使用触摸在iphone应用程序中绘制线条事件

Question

我使用触摸事件绘制了签名我从论坛上获得了代码，它的工作正常，但问题是它没有画出正确的线条，就好像我们将线条画成线条一样在该行崩溃阿里这里是我的代码

这里是我绘画的屏幕

- (void)viewDidLoad { 
    [super viewDidLoad]; 
drawImage = [[UIImageView alloc] initWithImage:nil]; 
drawImage.frame = self.view.frame; 
[self.view addSubview:drawImage]; 
self.view.backgroundColor = [UIColor lightGrayColor]; 
mouseMoved = 0; 
    } 

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

mouseSwiped = NO; 
UITouch *touch = [touches anyObject]; 

if ([touch tapCount] == 2) { 
    drawImage.image = nil; 
    return; 
} 

lastPoint = [touch locationInView:self.view]; 
lastPoint.y -= 20; 

    } 


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

    mouseSwiped = YES; 

UITouch *touch = [touches anyObject]; 
CGPoint currentPoint = [touch locationInView:self.view]; 
currentPoint.y -= 20; 


UIGraphicsBeginImageContext(self.view.frame.size); 
[drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; 
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); 
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0); 
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0); 
CGContextBeginPath(UIGraphicsGetCurrentContext()); 
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y); 
CGContextStrokePath(UIGraphicsGetCurrentContext()); 
drawImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); 

lastPoint = currentPoint; 

mouseMoved++; 

if (mouseMoved == 10) { 
    mouseMoved = 0; 
} 

    } 

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

    UITouch *touch = [touches anyObject]; 

    if ([touch tapCount] == 2) { 
    drawImage.image = nil; 
    return; 
    } 


    if(!mouseSwiped) { 
    UIGraphicsBeginImageContext(self.view.frame.size); 
    [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; 
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); 
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0); 
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0); 
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
    CGContextStrokePath(UIGraphicsGetCurrentContext()); 
    CGContextFlush(UIGraphicsGetCurrentContext()); 
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 
     } 
      } 

Answer 1

您可以添加按钮，按下该按钮的箭头是添加屏幕，你可以旋转和使用触摸调整大小。