Setting masked corners in Interface Builder

问题

What type of value is [.layerMaxXMinYCorner, .layerMinXMinYCorner]? Is it possible to set this parameter on a View in Interface Builder? I know how to set layer.borderWidth, layer.borderUIColor and layer.cornerRadius in the Identity Inspector, but I can't figure out the right Type and Value to use for masked corners.

Thanks!

Jake

Update: here are the integer values for each combination (in terms of which are rounded):

0: no rounded corners
1: top left
2: top right
3: top left & right (both top corners)
4: bottom left
5: top & bottom left (both left corners)
6: top right & bottom left
7: top left & right, bottom left (all corners except bottom right)
8: bottom right
9: top left, bottom right
10: top & bottom right (both right corners)
11: both top corners, bottom right (all corners except bottom left)
12: bottom left & right (both bottom corners)
13: bottom left & right, top left (all corners except top right)
14: bottom left & right, top right (all corners except top left)
15: all corners rounded

Top left is in 1, 3, 5, 7, 9, 11, 13, 15
Top right is in 2-3, 6-7, 10-11, 14-15
Bottom left is in 4-7, 12-15
Bottom right is in 8-15
Both top corners are in 3, 7, 11, 15
Both right corners are in 10-11, 14,15
Both bottom corners are in 12-15
Both left corners are in 5, 7, 13, 15

回答1:

maskedCorners is a CACornerMask, which is an OptionSet, or bit mask. The raw value is an integer: in code, you can try printing the value of someView.layer.maskedCorners.rawValue, or setting it via someView.layer.maskedCorners.setValue(3, forKey: "maskedCorners").

So you should be able to set the value of layer.maskedCorners to the integer 3 (or whatever you need) in Interface Builder, and I don't see why it would be unsafe to do this. Though it will be a pain to figure out what set of corners that integer value actually maps to if you forget.

回答2:

Did not check if it works, but you may try c:

(Don't forget to apply the mask to your view 🌚)

@IBDesignable
class ViewController: UIViewController {
    // Preprocessor macro, you won't be able 
    // to use code inside this "if" statement from your... code
    // Just use cornerMask property directly
    #if TARGET_INTERFACE_BUILDER
    @IBInspectable
    var topLeft: Bool = false {
        didSet {
            updateCornerMask()
        }
    }

    @IBInspectable
    var topRight: Bool = false {
        didSet {
            updateCornerMask()
        }
    }

    @IBInspectable
    var bottomLeft: Bool = false {
        didSet {
            updateCornerMask()
        }
    }

    @IBInspectable
    var bottomRight: Bool = false {
        didSet {
            updateCornerMask()
        }
    }

    func updateCornerMask() {
        cornerMask = CACornerMask(
            TL: topLeft,
            TR: topRight,
            BL: bottomLeft,
            BR: bottomRight)
    }
    #endif

    var cornerMask: CACornerMask?
}

extension CACornerMask {
    init(TL: Bool = false, TR: Bool = false, BL: Bool = false, BR: Bool = false) {
        var value: UInt = 0
        if TL { value += 1 }
        if TR { value += 2 }
        if BL { value += 4 }
        if BR { value += 8 }

        self.init(rawValue: value)
    }
}

// And yeah maybe using UIView makes more sense 🙃

来源：https://stackoverflow.com/questions/47699095/setting-masked-corners-in-interface-builder

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ios

uiview

interface-builder