我有一个 UIImageView。在里面我正在画一条线机智用户触摸事件。问题是可以在 UIImageview 的任何地方画线，但我喜欢只用图像模式画线。
例如，看这张图片。我只需要在图像图案上画线。
这是我的代码:
-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
touchPoint = [touch locationInView:self.imgColor];
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
[path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];
startingPoint=touchPoint;
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor redColor] CGColor];
[self.imgColor.layer addSublayer:shapeLayer];
[arrLayer addObject:shapeLayer];
NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);
}
我希望有人能解决我的问题。
最佳答案
你可以试试这个。
假设您有一个名为 maskPath 的 bezierPath，在我的例子中它是 textPath，用于屏蔽 imageView。
我正在使用一个简单的 maskView，它在 imageView 上绘制字母 Q。
添加 maskPath:(向 imageView 添加一个简单的 Q 形蒙版)
-(void)applyMask{
//// Text Drawing
textPath = [UIBezierPath bezierPath];
[textPath moveToPoint: CGPointMake(181, 179.8)];
[textPath addLineToPoint: CGPointMake(166, 197.2)];
[textPath addLineToPoint: CGPointMake(189.7, 216.1)];
[textPath addCurveToPoint: CGPointMake(160, 222.1) controlPoint1: CGPointMake(180.1, 220.1) controlPoint2: CGPointMake(170.2, 222.1)];
[textPath addCurveToPoint: CGPointMake(126.4, 214.45) controlPoint1: CGPointMake(147, 222.1) controlPoint2: CGPointMake(135.8, 219.55)];
[textPath addCurveToPoint: CGPointMake(103.3, 194.2) controlPoint1: CGPointMake(117, 209.35) controlPoint2: CGPointMake(109.3, 202.6)];
[textPath addCurveToPoint: CGPointMake(90.1, 165.85) controlPoint1: CGPointMake(97.3, 185.8) controlPoint2: CGPointMake(92.9, 176.35)];
[textPath addCurveToPoint: CGPointMake(85.9, 133.9) controlPoint1: CGPointMake(87.3, 155.35) controlPoint2: CGPointMake(85.9, 144.7)];
[textPath addCurveToPoint: CGPointMake(90.1, 101.95) controlPoint1: CGPointMake(85.9, 123.1) controlPoint2: CGPointMake(87.3, 112.45)];
[textPath addCurveToPoint: CGPointMake(103.3, 73.6) controlPoint1: CGPointMake(92.9, 91.45) controlPoint2: CGPointMake(97.3, 82)];
[textPath addCurveToPoint: CGPointMake(126.4, 53.35) controlPoint1: CGPointMake(109.3, 65.2) controlPoint2: CGPointMake(117, 58.45)];
[textPath addCurveToPoint: CGPointMake(160, 45.7) controlPoint1: CGPointMake(135.8, 48.25) controlPoint2: CGPointMake(147, 45.7)];
[textPath addCurveToPoint: CGPointMake(193.6, 53.35) controlPoint1: CGPointMake(173, 45.7) controlPoint2: CGPointMake(184.2, 48.25)];
[textPath addCurveToPoint: CGPointMake(216.7, 73.6) controlPoint1: CGPointMake(203, 58.45) controlPoint2: CGPointMake(210.7, 65.2)];
[textPath addCurveToPoint: CGPointMake(229.9, 101.95) controlPoint1: CGPointMake(222.7, 82) controlPoint2: CGPointMake(227.1, 91.45)];
[textPath addCurveToPoint: CGPointMake(234.1, 133.9) controlPoint1: CGPointMake(232.7, 112.45) controlPoint2: CGPointMake(234.1, 123.1)];
[textPath addCurveToPoint: CGPointMake(228.1, 171.85) controlPoint1: CGPointMake(234.1, 147.1) controlPoint2: CGPointMake(232.1, 159.75)];
[textPath addCurveToPoint: CGPointMake(209.5, 202.6) controlPoint1: CGPointMake(224.1, 183.95) controlPoint2: CGPointMake(217.9, 194.2)];
[textPath addLineToPoint: CGPointMake(181, 179.8)];
[textPath closePath];
[textPath moveToPoint: CGPointMake(244, 259.3)];
[textPath addLineToPoint: CGPointMake(258.4, 241.3)];
[textPath addLineToPoint: CGPointMake(230.2, 219.1)];
[textPath addCurveToPoint: CGPointMake(254.5, 180.7) controlPoint1: CGPointMake(241, 208.3) controlPoint2: CGPointMake(249.1, 195.5)];
[textPath addCurveToPoint: CGPointMake(262.6, 133.9) controlPoint1: CGPointMake(259.9, 165.9) controlPoint2: CGPointMake(262.6, 150.3)];
[textPath addCurveToPoint: CGPointMake(256.15, 91.75) controlPoint1: CGPointMake(262.6, 119.3) controlPoint2: CGPointMake(260.45, 105.25)];
[textPath addCurveToPoint: CGPointMake(236.8, 55.9) controlPoint1: CGPointMake(251.85, 78.25) controlPoint2: CGPointMake(245.4, 66.3)];
[textPath addCurveToPoint: CGPointMake(204.7, 31) controlPoint1: CGPointMake(228.2, 45.5) controlPoint2: CGPointMake(217.5, 37.2)];
[textPath addCurveToPoint: CGPointMake(160, 21.7) controlPoint1: CGPointMake(191.9, 24.8) controlPoint2: CGPointMake(177, 21.7)];
[textPath addCurveToPoint: CGPointMake(115.3, 31) controlPoint1: CGPointMake(143, 21.7) controlPoint2: CGPointMake(128.1, 24.8)];
[textPath addCurveToPoint: CGPointMake(83.2, 55.9) controlPoint1: CGPointMake(102.5, 37.2) controlPoint2: CGPointMake(91.8, 45.5)];
[textPath addCurveToPoint: CGPointMake(63.85, 91.75) controlPoint1: CGPointMake(74.6, 66.3) controlPoint2: CGPointMake(68.15, 78.25)];
[textPath addCurveToPoint: CGPointMake(57.4, 133.9) controlPoint1: CGPointMake(59.55, 105.25) controlPoint2: CGPointMake(57.4, 119.3)];
[textPath addCurveToPoint: CGPointMake(63.85, 176.05) controlPoint1: CGPointMake(57.4, 148.5) controlPoint2: CGPointMake(59.55, 162.55)];
[textPath addCurveToPoint: CGPointMake(83.2, 211.9) controlPoint1: CGPointMake(68.15, 189.55) controlPoint2: CGPointMake(74.6, 201.5)];
[textPath addCurveToPoint: CGPointMake(115.3, 236.65) controlPoint1: CGPointMake(91.8, 222.3) controlPoint2: CGPointMake(102.5, 230.55)];
[textPath addCurveToPoint: CGPointMake(160, 245.8) controlPoint1: CGPointMake(128.1, 242.75) controlPoint2: CGPointMake(143, 245.8)];
[textPath addCurveToPoint: CGPointMake(211.3, 233.2) controlPoint1: CGPointMake(179.8, 245.8) controlPoint2: CGPointMake(196.9, 241.6)];
[textPath addLineToPoint: CGPointMake(244, 259.3)];
[textPath closePath];
[UIColor.blackColor setFill];
[textPath fill];
maskLayer = [CAShapeLayer layer];
maskLayer.path = [textPath CGPath];
maskLayer.strokeColor = [[UIColor blackColor] CGColor];
maskLayer.lineWidth = 3.0;
maskLayer.fillColor = [[UIColor redColor] CGColor];
[self.imgView.layer addSublayer:maskLayer];
}
你已经有了方法:
-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchPoint = [touch locationInView:self.imgView];
if ([textPath containsPoint:touchPoint]) {
path=nil; //this is not need,unless u want to start a new path everytime this condition executes.
path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
[path addLineToPoint: CGPointMake(_startingPoint.x,_startingPoint.y)];
_startingPoint=touchPoint;
drawLayer = [CAShapeLayer layer];
drawLayer.path = [path CGPath];
drawLayer.strokeColor = [[UIColor blackColor] CGColor];
drawLayer.lineWidth = 3.0;
drawLayer.fillColor = [[UIColor redColor] CGColor];
[self.imgView.layer addSublayer:drawLayer];
NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);
}
}
您现在可以验证触摸点是否位于 textPath 中，而 whcih 是 bezierPath。
如果触摸点在 textPath 中，则允许绘制，否则不绘制。
结果会是这样的:
如您所见，此代码将允许您仅在屏蔽路径中绘制。
如果你想在 textPath 之外绘制，那么你可以简单地做:
if (![textPath containsPoint:touchPoint]) {
path=nil; //this is not need,unless u want to start a new path everytime this condition executes.
path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
[path addLineToPoint:CGPointMake(_startingPoint.x,_startingPoint.y)];
_startingPoint=touchPoint;
drawLayer = [CAShapeLayer layer];
drawLayer.path = [path CGPath];
drawLayer.strokeColor = [[UIColor blackColor] CGColor];
drawLayer.lineWidth = 3.0;
drawLayer.fillColor = [[UIColor redColor] CGColor];
[self.imgView.layer addSublayer:drawLayer];
NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);
}
注意:在绘制线条时需要注意触摸移动方法。由于贝塞尔路径方法 addLineToPoint 将向 touchPoint 添加线，并且这条线可能会穿过 maskedPath。您需要确保关闭之前的 bezier 路径并开始一个新的路径，以避免在蒙版区域的外部绘制线条。
关于ios - 如何准确地在图像图案上画线，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34693651/
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