8

我正在使用此代码将图层应用于 UIview：

mask = [[CAShapeLayer alloc] init];
mask.frame = baseView.layer.bounds;
CGRect biggerRect = CGRectMake(mask.frame.origin.x, mask.frame.origin.y, mask.frame.size.width, mask.frame.size.height);
CGRect smallerRect = CGRectMake(0.0f, 0.0f, 0.0f, 0.0f);

UIBezierPath *maskPath = [UIBezierPath bezierPath];
[maskPath moveToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];

[maskPath moveToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];

mask.path = maskPath.CGPath;
[mask setFillRule:kCAFillRuleEvenOdd];
mask.fillColor = [[UIColor blackColor] CGColor];
baseView.layer.mask = mask;

由于我要剪切的矩形发生了变化，我想知道是否有一种快速的方法来更改蒙版的大小，而不是仅仅从 UIview 中删除它并以不同的尺寸重新应用它：

例如

[mask removeFromSuperlayer];

和...

mask = [[CAShapeLayer alloc] init];
mask.frame = baseView.layer.bounds;
CGRect biggerRect = CGRectMake(mask.frame.origin.x, mask.frame.origin.y, mask.frame.size.width, mask.frame.size.height);
CGRect smallerRect = CGRectMake(0.0f, 100.0f, 200.0f, 200.0f);

UIBezierPath *maskPath = [UIBezierPath bezierPath];
[maskPath moveToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];

[maskPath moveToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];

mask.path = maskPath.CGPath;
[mask setFillRule:kCAFillRuleEvenOdd];
mask.fillColor = [[UIColor blackColor] CGColor];
baseView.layer.mask = mask;
4

1 回答 1

11

如果您问是否可以重新塑造面具而不必每次都绘制路径，很遗憾不是。您可以通过设置的transform属性保持蒙版形状相同并在蒙版上执行转换，CAShapeLayer但如果您需要蒙版采用不同的形状，则必须通过创建新路径来绘制该形状。但是UIView每次你需要改变它的形状时，没有必要把它从面具上取下来并创建一个全新的面具。简单地设置 CAShapeLayer 的path属性，同时它仍然掩盖 ，UIView就足以使更改发生：

- (void)remask
{
    CAShapeLayer *mask = (CAShapeLayer *)self.view.layer.mask;

    CGRect biggerRect = CGRectMake(mask.frame.origin.x, mask.frame.origin.y, mask.frame.size.width, mask.frame.size.height);
    CGRect smallerRect = CGRectMake(0.0f, 100.0f, 200.0f, 200.0f);

    UIBezierPath *maskPath = [UIBezierPath bezierPath];
    [maskPath moveToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMaxY(biggerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMaxY(biggerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMinY(biggerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];

    [maskPath moveToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMaxY(smallerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMaxY(smallerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMinY(smallerRect))];
    [maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];

    mask.path = maskPath.CGPath;
}

附带说明一下，您是否知道，您可以使用以下代码创建蒙版路径，而不是手动绘制每个矩形：

mask = [[CAShapeLayer alloc] init];
mask.frame = baseView.layer.bounds;
CGRect biggerRect = CGRectMake(mask.frame.origin.x, mask.frame.origin.y, mask.frame.size.width, mask.frame.size.height);
CGRect smallerRect = CGRectMake(0.0f, 100.0f, 200.0f, 200.0f);

CGMutablePathRef maskPath = CGPathCreateMutable();
CGPathAddRect(maskPath, NULL, biggerRect);
CGPathAddRect(maskPath, NULL, smallerRect);

mask.path = maskPath;
[mask setFillRule:kCAFillRuleEvenOdd];
mask.fillColor = [[UIColor blackColor] CGColor];
baseView.layer.mask = mask;

CGPathRelease(maskPath);

我想我只是指出它，因为它将来可能对你方便。

于 2013-03-28T20:40:02.130 回答