I have a CALayer hosting view, which I would like to be able to zoom, scroll around and click in. If I embed it in a scrollview, the scrolling works fine, but zooming causes the contents to fly away everywhere. If I don't embed it in a scrollview, I can get the zooming working nicely using CATransform3DMakeScale, but then I have problems with panning, and being able to select objects.
What would be the recommended way to approach this - before I try and work it out with the wrong option.
(If you have any source that does a similar thing, I would be very grateful to see it.)
I got inspired here at Apple sample codes
Also look at the Optimizing Drawing and Scrolling on OS X WWDC 2013 video
The CALayer
embedded in ScrollView
flown because the ScrollView
wasn't the Core Animation layer (ScrollView.wantsLayer = true
).
Here example in Swift:
@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
}
}
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