带有 NSScrollView 的 CALayer，缩放平移和点击

Question

我有一个 CALayer 托管视图，我希望能够对其进行缩放、滚动和点击。如果我将它嵌入到滚动视图中，滚动效果很好，但是缩放会导致内容到处飞散。如果我不将它嵌入到滚动视图中，我可以使用 CATransform3DMakeScale 很好地进行缩放，但是我在平移和选择对象时遇到了问题。

在我尝试用错误的选项解决之前，推荐的解决方法是什么。

（如果您有任何类似的来源，我将非常感激。）

Answer 1

我在Apple sample codes 得到了启发

另请查看Optimizing Drawing and Scrolling on OS X WWDC 2013 video

嵌入在ScrollView 中的CALayer 飞了起来，因为ScrollView 不是核心动画层 (ScrollView.wantsLayer = true)。

这里是 Swift 中的示例：

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
    var win: NSWindow!

    func applicationDidFinishLaunching(aNotification: NSNotification) {

        win = NSWindow(contentRect: NSRect(x: 200, y: 200, width: 500, height: 500),
            styleMask: NSTitledWindowMask,
            backing: NSBackingStoreType.Buffered,
            defer: false)

        win.makeKeyAndOrderFront(win)

        let scrollView = NSScrollView()
        scrollView.allowsMagnification = true
        scrollView.hasHorizontalScroller = true
        scrollView.hasVerticalScroller = true
        scrollView.wantsLayer = true

        scrollView.contentView = CenteredClipView()
        scrollView.documentView = MyView()
        scrollView.backgroundColor = NSColor.controlColor()

        win.contentView = scrollView
    }
}

class MyView: NSView {
    var drawn = false

    override func updateLayer() {
        super.updateLayer()

        if !drawn {
            drawn = true

            frame = (superview! as NSView).frame

            var shape = CAShapeLayer()
            let p = CGPathCreateMutable()
            CGPathAddEllipseInRect(p, nil, frame)
            CGPathMoveToPoint(p, nil, bounds.maxX, 0)
            CGPathAddLineToPoint(p, nil, 0, bounds.maxY)
            shape.path = p
            shape.lineWidth = 5
            shape.fillColor = NSColor.whiteColor().CGColor
            shape.strokeColor = NSColor.selectedControlColor().CGColor
            shape.lineDashPattern = [5, 5]

            let ant = CABasicAnimation(keyPath: "lineDashPhase")
            ant.fromValue = 0
            ant.toValue = 1000000
            ant.duration = 10000
            ant.repeatCount = 10000
            shape.addAnimation(ant, forKey: "lineDashPhase")

            layer?.addSublayer(shape)
        }
    }
}

class CenteredClipView: NSClipView {
    override func constrainBoundsRect(proposedBounds: NSRect) -> NSRect {
        var rect = super.constrainBoundsRect(proposedBounds)

        if let containerView = documentView? as? NSView {
            if rect.size.width > containerView.frame.size.width {
                rect.origin.x = (containerView.frame.width - rect.width ) / 2
            }

            if rect.size.height > containerView.frame.size.height {
                rect.origin.y = (containerView.frame.height - rect.height ) / 2
            }
        }

        return rect
    }
}