使用touches事件在iphone应用程序中绘制线条

Question

我正在使用触摸事件绘制签名我从论坛得到的代码它工作正常但问题是它不绘制线条正确，如果我们绘制线作为阿里它崩溃阿里在这里是我的代码

这是我绘图的屏幕

   - (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

您可以在按下该按钮时添加按钮，在屏幕上添加箭头，您可以使用触摸旋转和调整大小。