I am trying to create a tooltip with bold text. Some apple apps on macOS use this behaviour. How do I achieve this?
My code currently
btn.tooltip = "Open Options"
//tooltip doesn't accept attributed strings.
Here is an example (screenshot of Xcode using this behaviour) of what I'm trying to achieve.
It seems there is no built-in default behavior for tooltips with NSAttributedStrings. As a solution, one could implement a floating NSPanel.
As long as the mouse is within the button bounds for at least a certain period of time, you could show a popover with an NSAttributedString. You can use the mouseEntered and mouseExited events for this purpose. Unfortunately, this requires that you subclass the NSButton.
Complete, Self-contained Swift Program
From a ViewController we would most likely to call it like this:
import Cocoa
class ViewController: NSViewController {
private let button = ToolTipButton()
override func viewDidLoad() {
super.viewDidLoad()
button.title = "Hoover over me"
let headline = "isEnabled"
let body = "A Boolean value that determines whether the label draws its text in an enabled state."
button.setToolTip(headline: headline, body: body)
view.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
])
}
}
The ToolTipButton class could look like this:
import Cocoa
class ToolTipButton: NSButton {
private var toolTipHandler: ToolTipHandler?
func setToolTip(headline: String, body: String) {
toolTipHandler = ToolTipHandler(headline: headline, body: body)
}
override func mouseEntered(with event: NSEvent) {
toolTipHandler?.mouseEntered(into: self)
}
override func mouseExited(with event: NSEvent) {
toolTipHandler?.mouseExited()
}
override func updateTrackingAreas() {
super.updateTrackingAreas()
toolTipHandler?.updateTrackingAreas(for: self)
}
}
Finally the ToolTipHandler could look like this:
import Cocoa
final class ToolTipHandler {
private var headline: String
private var body: String
private var mouseStillInside = false
private var panel: NSPanel?
init(headline: String, body: String) {
self.headline = headline
self.body = body
}
func setToolTip(headline: String, body: String) {
self.headline = headline
self.body = body
}
func mouseEntered(into view: NSView) {
mouseStillInside = true
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
self.showToolTipIfMouseStillInside(for: view)
}
}
func mouseExited() {
mouseStillInside = false
panel?.close()
panel = nil
}
func updateTrackingAreas(for view: NSView) {
for trackingArea in view.trackingAreas {
view.removeTrackingArea(trackingArea)
}
let options: NSTrackingArea.Options = [.mouseEnteredAndExited, .activeAlways]
let trackingArea = NSTrackingArea(rect: view.bounds, options: options, owner: view, userInfo: nil)
view.addTrackingArea(trackingArea)
}
private func showToolTipIfMouseStillInside(for view: NSView) {
guard mouseStillInside && panel == nil else { return }
panel = Self.showToolTip(sender: view, headline: headline, body: body)
}
private static func showToolTip(sender: NSView, headline: String, body: String) -> NSPanel {
let panel = NSPanel()
panel.styleMask = [NSWindow.StyleMask.borderless]
panel.level = .floating
let attributedToolTip = Self.attributedToolTip(headline: headline, body: body)
panel.contentViewController = ToolTipViewController(attributedToolTip: attributedToolTip, width: 200.0)
let lowerLeftOfSender = sender.convert(NSPoint(x: sender.bounds.minX + 4.0, y: sender.bounds.maxY + 10.0), to: nil)
let newOrigin = sender.window?.convertToScreen(NSRect(origin: lowerLeftOfSender, size: .zero)).origin ?? .zero
panel.setFrameOrigin(newOrigin)
panel.orderFrontRegardless()
return panel
}
private static func attributedToolTip(headline: String, body: String) -> NSAttributedString {
let headlineAttributes: [NSAttributedString.Key: Any] = [
.foregroundColor: NSColor.controlTextColor,
.font: NSFont.boldSystemFont(ofSize: 11)
]
let bodyAttributes: [NSAttributedString.Key: Any] = [
.foregroundColor: NSColor.controlTextColor,
.font: NSFont.systemFont(ofSize: 11)
]
let tooltip = NSMutableAttributedString(string: headline, attributes: headlineAttributes)
tooltip.append(NSAttributedString(string: "\n" + body , attributes: bodyAttributes))
return tooltip
}
}
Finally the ToolTipViewController:
import Cocoa
final class ToolTipViewController: NSViewController {
private let attributedToolTip: NSAttributedString
private let width: CGFloat
init(attributedToolTip: NSAttributedString, width: CGFloat) {
self.attributedToolTip = attributedToolTip
self.width = width
super.init(nibName: nil, bundle: nil)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func loadView() {
view = NSView()
view.wantsLayer = true
view.layer?.backgroundColor = NSColor.controlBackgroundColor.cgColor
}
override func viewDidLoad() {
super.viewDidLoad()
setupUI()
}
private func setupUI() {
let label = NSTextField()
label.isEditable = false
label.isBezeled = false
label.attributedStringValue = attributedToolTip
label.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(label)
NSLayoutConstraint.activate([
label.topAnchor.constraint(equalTo: view.topAnchor, constant: 1.0),
label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 1.0),
label.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -1.0),
label.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -1.0),
label.widthAnchor.constraint(equalToConstant: width)
])
}
}
Depending on the actual requirements, adjustments are probably necessary. But it should at least be a starting point.
Demo
The source code and full-length version of this answer are at this GitHub repo.
Separately from that repo I also extracted the code into a Swift Package, so I could use it in other projects. The dependency to add to your project is "https://github.com/chipjarred/CustomToolTip.git". Use "from" version 1.0.0 or branch "main".
What follows is the version trimmed down to a length SO would let me post.
Stephan's answer prompted me to do my own implementation of tool tips. My solution produces tool tips that look like the standard tool tips, except you can put any view you like inside them, so not just styled text, but images... you could even use a WebKit view, if you wanted to.
Obviously it doesn't make sense to put some kinds of views in it. Anything that only makes sense with user interaction would be meaningless since the tool tip would disappear as soon as they move the mouse cursor to interact with it... though that would be good April Fools joke.
Before I get to my solution, I want to mention that there is another way to make Stephan's solution a little easier to use, which is to use the "decorator" pattern by subclassing NSView to wrap another view. Your wrapper is the part that hooks into to the tool tips, and handles the tracking areas. Just make sure you forward those calls to the wrapped view too, in case it also has tracking areas (perhaps it changes the cursor or something, like NSTextView does.) Using a decorator means you don't subclass every view... just put the view you want to add a tool tip inside of a ToolTippableView or whatever you decide to call it. I don't think you'll need to override all NSView methods as long as you wrap the view by adding it to your subviews. The view heirarchy and responder chain should take care of dispatching the events and messages you're not interested in to the subview. You should only need to forward the ones you handle for the tool tips (mouseEntered, mouseExited, etc...)
My solution
However, I went to an evil extreme... and spent way more time on it than I probably should have, but it seemed like something I might want to use at some point. I swizzled ("monkey patched") NSView methods to handle custom tool tips, which combined with an extension on NSView means I don't have subclass anything to add custom tool tips, I can just write:
myView.customToolTip = myCustomToolTipContent
where myCustomToolTipContent is whatever NSView I want to display in the tool tip.
The Tool Tip itself
The main thing is the tool tip itself. It's just a window. It sizes itself to whatever content you put in it, so make sure you've set your tip content's view frame to the size you want before setting customToolTip. Here's the tool tip window code:
// -------------------------------------
/**
Window for displaying custom tool tips.
*/
class CustomToolTipWindow: NSWindow
{
// -------------------------------------
static func makeAndShow(
toolTipView: NSView,
for owner: NSView) -> CustomToolTipWindow
{
let window = CustomToolTipWindow(toolTipView: toolTipView, for: owner)
window.orderFront(self)
return window
}
// -------------------------------------
init(toolTipView: NSView, for toolTipOwner: NSView)
{
super.init(
contentRect: toolTipView.bounds,
styleMask: [.borderless],
backing: .buffered,
defer: false
)
self.backgroundColor = NSColor.windowBackgroundColor
let border = BorderedView.init(frame: toolTipView.frame)
border.addSubview(toolTipView)
contentView = border
contentView?.isHidden = false
reposition(relativeTo: toolTipOwner)
}
// -------------------------------------
deinit { orderOut(nil) }
// -------------------------------------
/**
Place the tool tip window's frame in a sensible place relative to the
tool tip's owner view on the screen.
If the current layout direction is left-to-right, the preferred location is
below and shifted to the right relative to the owner. If the layout
direction is right-to-left, the preferred location is below and shift to
the left relative to the owner.
The preferred location is overridden when any part of the tool tip would be
drawn off of the screen. For conflicts with horizontal edges, it is moved
to be some "safety" distance within the screen bounds. For conflicts with
the bottom edge, the tool tip is positioned above the owning view.
Non-flipped coordinates (y = 0 at bottom) are assumed.
*/
func reposition(relativeTo toolTipOwner: NSView)
{
guard let ownerRect =
toolTipOwner.window?.convertToScreen(toolTipOwner.frame),
let screenRect = toolTipOwner.window?.screen?.visibleFrame
else { return }
let hPadding: CGFloat = ownerRect.width / 2
let hSafetyPadding: CGFloat = 20
let vPadding: CGFloat = 0
var newRect = frame
newRect.origin = ownerRect.origin
// Position tool tip window slightly below the onwer on the screen
newRect.origin.y -= newRect.height + vPadding
if NSApp.userInterfaceLayoutDirection == .leftToRight
{
/*
Position the tool tip window to the right relative to the owner on
the screen.
*/
newRect.origin.x += hPadding
// Make sure we're not drawing off the right edge
newRect.origin.x = min(
newRect.origin.x,
screenRect.maxX - newRect.width - hSafetyPadding
)
}
else
{
/*
Position the tool tip window to the left relative to the owner on
the screen.
*/
newRect.origin.x -= hPadding
// Make sure we're not drawing off the left edge
newRect.origin.x =
max(newRect.origin.x, screenRect.minX + hSafetyPadding)
}
/*
Make sure we're not drawing off the bottom edge of the visible area.
Non-flipped coordinates (y = 0 at bottom) are assumed.
If we are, move the tool tip above the onwer.
*/
if newRect.minY < screenRect.minY {
newRect.origin.y = ownerRect.maxY + vPadding
}
self.setFrameOrigin(newRect.origin)
}
// -------------------------------------
/// Provides thin border around the tool tip.
private class BorderedView: NSView
{
override func draw(_ dirtyRect: NSRect)
{
super.draw(dirtyRect)
guard let context = NSGraphicsContext.current?.cgContext else {
return
}
context.setStrokeColor(NSColor.black.cgColor)
context.stroke(self.frame, width: 2)
}
}
}
The tool tip window is the easy part. This implementation positions the window relative to its owner (the view to which the tool tip is attached) while also avoiding drawing offscreen. I don't handle the pathalogical case where the tool tip is so large that it can't fit onto screen without obscuring the thing it's a tool tip for. Nor do I handle the case where the thing you're attaching the tool tip to is so large that even though the tool tip itself is a reasonable size, it can't go outside of the area occupied by the view to which it's attached. That case shouldn't be too hard to handle. I just didn't do it. I do handle responding to the currently set layout direction.
If you want to incorporate it into another solution, the code to show the tool tip is
let toolTipWindow = CustomToolTipWindow.makeAndShow(toolTipView: toolTipView, for: ownerView)
where toolTipView is the view to be displayed in the tool tip. ownerView is the view to which you're attaching the tool tip. You'll need to store toolTipWindow somewhere, for example in Stephan's ToolTipHandler.
To hide the tool tip:
toolTipWindow.orderOut(self)
or just set the last reference you keep to it to nil.
I think that gives you everything you need to incorporate it into another solution if you like.
Tool Tip handling code
As a small convenience, I use this extension on NSTrackingArea
// -------------------------------------
/*
Convenice extension for updating a tracking area's `rect` property.
*/
fileprivate extension NSTrackingArea
{
func updateRect(with newRect: NSRect) -> NSTrackingArea
{
return NSTrackingArea(
rect: newRect,
options: options,
owner: owner,
userInfo: nil
)
}
}
Since I'm swizzling NSVew (actually its subclasses as you add tool tips), I don't have a ToolTipHandler-like object. I just put it all in an extension on NSView and use global storage. To do that I have a ToolTipControl struct and a ToolTipControls wrapper around an array of them:
// -------------------------------------
/**
Data structure to hold information used for holding the tool tip and for
controlling when to show or hide it.
*/
fileprivate struct ToolTipControl
{
/**
`Date` when mouse was last moved within the tracking area. Should be
`nil` when the mouse is not in the tracking area.
*/
var mouseEntered: Date?
/// View to which the custom tool tip is attached
weak var onwerView: NSView?
/// The content view of the tool tip
var toolTipView: NSView?
/// `true` when the tool tip is currently displayed. `false` otherwise.
var isVisible: Bool = false
/**
The tool tip's window. Should be `nil` when the tool tip is not being
shown.
*/
var toolTipWindow: NSWindow? = nil
init(
mouseEntered: Date? = nil,
hostView: NSView,
toolTipView: NSView? = nil)
{
self.mouseEntered = mouseEntered
self.onwerView = hostView
self.toolTipView = toolTipView
}
}
// -------------------------------------
/**
Data structure for holding `ToolTipControl` instances. Since we only need
one collection of them for the application, all its methods and properties
are `static`.
*/
fileprivate struct ToolTipControls
{
private static var controlsLock = os_unfair_lock()
private static var controls: [ToolTipControl] = []
// -------------------------------------
static func getControl(for hostView: NSView) -> ToolTipControl? {
withLock { return controls.first { $0.onwerView === hostView } }
}
// -------------------------------------
static func setControl(for hostView: NSView, to control: ToolTipControl)
{
withLock
{
if let i = index(for: hostView) { controls[i] = control }
else { controls.append(control) }
}
}
// -------------------------------------
static func removeControl(for hostView: NSView)
{
withLock
{
controls.removeAll {
$0.onwerView == nil || $0.onwerView === hostView
}
}
}
// -------------------------------------
private static func index(for hostView: NSView) -> Int? {
controls.firstIndex { $0.onwerView == hostView }
}
// -------------------------------------
private static func withLock<R>(_ block: () -> R) -> R
{
os_unfair_lock_lock(&controlsLock)
defer { os_unfair_lock_unlock(&controlsLock) }
return block()
}
// -------------------------------------
private init() { } // prevent instances
}
These are fileprivate in the same file as my extension on NSView. I also have to have a way to differentiate between my tracking areas and others the view might have. They have a userInfo dictionary that I use for that. I don't need to store different individualized information in each one, so I just make a global one I reuse.
fileprivate let bundleID = Bundle.main.bundleIdentifier ?? "com.CustomToolTips"
fileprivate let toolTipKeyTag = bundleID + "CustomToolTips"
fileprivate let customToolTipTag = [toolTipKeyTag: true]
And I need a dispatch queue:
fileprivate let dispatchQueue = DispatchQueue(
label: toolTipKeyTag,
qos: .background
)
NSView extension
My NSView extension has a lot in it, the vast majority of which is private, including swizzled methods, so I'll break it into pieces
In order to be able to attach a custom tool tip as easily as you do for a standard tool tip, I provide a computed property. In addition to actually setting the tool tip view, it also checks to see if Self (that is the particular subclass of NSView) has already been swizzled, and does that if it hasn't been, and it's adds the mouse tracking area.
// -------------------------------------
/**
Adds a custom tool tip to the receiver. If set to `nil`, the custom tool
tip is removed.
This view's `frame.size` will determine the size of the tool tip window
*/
public var customToolTip: NSView?
{
get { toolTipControl?.toolTipView }
set
{
Self.initializeCustomToolTips()
if let newValue = newValue
{
addCustomToolTipTrackingArea()
var current = toolTipControl ?? ToolTipControl(hostView: self)
current.toolTipView = newValue
toolTipControl = current
}
else { toolTipControl = nil }
}
}
// -------------------------------------
/**
Adds a tracking area encompassing the receiver's bounds that will be used
for tracking the mouse for determining when to show the tool tip. If a
tacking area already exists for the receiver, it is removed before the
new tracking area is set. This method should only be called when a new
tool tip is attached to the receiver.
*/
private func addCustomToolTipTrackingArea()
{
if let ta = trackingAreaForCustomToolTip {
removeTrackingArea(ta)
}
addTrackingArea(
NSTrackingArea(
rect: self.bounds,
options:
[.activeInActiveApp, .mouseMoved, .mouseEnteredAndExited],
owner: self,
userInfo: customToolTipTag
)
)
}
// -------------------------------------
/**
Returns the custom tool tip tracking area for the receiver.
*/
private var trackingAreaForCustomToolTip: NSTrackingArea?
{
trackingAreas.first {
$0.owner === self && $0.userInfo?[toolTipKeyTag] != nil
}
}
trackingAreaForCustomToolTip is where I use the global tag to sort my tracking area from any others that the view might have.
Of course, I also have to implement updateTrackingAreas and this where we start to see some of evidence of swizzling.
// -------------------------------------
/**
Updates the custom tooltip tracking aread when `updateTrackingAreas` is
called.
*/
#objc private func updateTrackingAreas_CustomToolTip()
{
if let ta = trackingAreaForCustomToolTip
{
removeTrackingArea(ta)
addTrackingArea(ta.updateRect(with: self.bounds))
}
else { addCustomToolTipTrackingArea() }
callReplacedMethod(for: #selector(self.updateTrackingAreas))
}
The method isn't called updateTrackingAreas because I'm not overriding it in the usual sense. I actually replace the implementation of the current class's updateTrackingAreas with the implementation of my updateTrackingAreas_CustomToolTip, saving off the original implementation so I can forward to it. callReplacedMethod where I do that forwarding. If you look into swizzling, you find lots of examples where people call what looks like an infinite recursion, but isn't because they exchange method implementations. That works most of the time, but it can subtly mess up the underlying Objective-C messaging because the selector used to call the old method is no longer the original selector. The way I've done it preserves the selector, which makes it less fragile when something depends on the actual selector remaining the same. There's more on swizzling in the full answer on GitHub I linked to above. For now, think of callReplacedMethod as similar to calling super if I were doing this by subclassing.
Then there's scheduling to show the tool tip. I do this kind of similarly to Stephan, but I wanted the behavior that the tool tip isn't shown until the mouse stops moving for a certain delay (1 second is what I currently use).
As I'm writing this, I just noticed that I do deviate from the standard behavior once the tool tip is displayed. The standard behavior is that once the tool tip is shown it continues to show the tool tip even if the mouse is moved as long as it remains in the tracking area. So once shown, the standard behavior doesn't hide the tool tip until the mouse leaves the tracking area. I hide it as soon as you move the mouse. Doing it the standard way is actually simpler, but the way I do it would allow for the tool tip to be shown over large views (for example a NSTextView for a large document) where it has to actually in the same area of the screen that it's owner occupies. I don't currently position the tool tip that way, but if I were to, you'd want any mouse movement to hide the tool tip, otherwise the tool tip would obscure part of what you need to interact with.
Anyway, here's what that scheduling code looks like
// -------------------------------------
/**
Controls how many seconds the mouse must be motionless within the tracking
area in order to show the tool tip.
*/
private var customToolTipDelay: TimeInterval { 1 /* seconds */ }
// -------------------------------------
/**
Schedules to potentially show the tool tip after `delay` seconds.
The tool tip is not *necessarily* shown as a result of calling this method,
but rather this method begins a sequence of chained asynchronous calls that
determine whether or not to display the tool tip based on whether the tool
tip is already visible, and how long it's been since the mouse was moved
withn the tracking area.
- Parameters:
- delay: Number of seconds to wait until determining whether or not to
display the tool tip
- mouseEntered: Set to `true` when calling from `mouseEntered`,
otherwise set to `false`
*/
private func scheduleShowToolTip(delay: TimeInterval, mouseEntered: Bool)
{
guard var control = toolTipControl else { return }
if mouseEntered
{
control.mouseEntered = Date()
toolTipControl = control
}
let asyncDelay: DispatchTimeInterval = .milliseconds(Int(delay * 1000))
dispatchQueue.asyncAfter(deadline: .now() + asyncDelay) {
[weak self] in self?.scheduledShowToolTip()
}
}
// -------------------------------------
/**
Display the tool tip now, *if* the mouse is in the tracking area and has
not moved for at least `customToolTipDelay` seconds. Otherwise, schedule
to check again after a short delay.
*/
private func scheduledShowToolTip()
{
let repeatDelay: TimeInterval = 0.1
/*
control.mouseEntered is set to nil when exiting the tracking area,
so this guard terminates the async chain
*/
guard let control = self.toolTipControl,
let mouseEntered = control.mouseEntered
else { return }
if control.isVisible {
scheduleShowToolTip(delay: repeatDelay, mouseEntered: false)
}
else if Date().timeIntervalSince(mouseEntered) >= customToolTipDelay
{
DispatchQueue.main.async
{ [weak self] in
if let self = self
{
self.showToolTip()
self.scheduleShowToolTip(
delay: repeatDelay,
mouseEntered: false
)
}
}
}
else { scheduleShowToolTip(delay: repeatDelay, mouseEntered: false) }
}
Earlier I gave the code for how to show and hide the tool tip window. Here are the functions where that code lives with its interaction with toolTipControl to control the corresponding loop.
// -------------------------------------
/**
Displays the tool tip now.
*/
private func showToolTip()
{
guard var control = toolTipControl else { return }
defer
{
control.mouseEntered = Date.distantPast
toolTipControl = control
}
guard let toolTipView = control.toolTipView else
{
control.isVisible = false
return
}
if !control.isVisible
{
control.isVisible = true
control.toolTipWindow = CustomToolTipWindow.makeAndShow(
toolTipView: toolTipView,
for: self
)
}
}
// -------------------------------------
/**
Hides the tool tip now.
*/
private func hideToolTip(exitTracking: Bool)
{
guard var control = toolTipControl else { return }
control.mouseEntered = exitTracking ? nil : Date()
control.isVisible = false
let window = control.toolTipWindow
control.toolTipWindow = nil
window?.orderOut(self)
control.toolTipWindow = nil
toolTipControl = control
print("Hiding tool tip")
}
The only thing that's left before getting to the actual swizzling is handling the mouse movements. I do this with mouseEntered, mouseExited and mouseMoved, or rather, their swizzled implementations:
// -------------------------------------
/**
Schedules potentially showing the tool tip when the `mouseEntered` is
called.
*/
#objc private func mouseEntered_CustomToolTip(with event: NSEvent)
{
scheduleShowToolTip(delay: customToolTipDelay, mouseEntered: true)
callReplacedEventMethod(
for: #selector(self.mouseEntered(with:)),
with: event
)
}
// -------------------------------------
/**
Hides the tool tip if it's visible when `mouseExited` is called, cancelling
further `async` chaining that checks to show it.
*/
#objc private func mouseExited_CustomToolTip(with event: NSEvent)
{
hideToolTip(exitTracking: true)
callReplacedEventMethod(
for: #selector(self.mouseExited(with:)),
with: event
)
}
// -------------------------------------
/**
Hides the tool tip if it's visible when `mousedMoved` is called, and
resets the time for it to be displayed again.
*/
#objc private func mouseMoved_CustomToolTip(with event: NSEvent)
{
hideToolTip(exitTracking: false)
callReplacedEventMethod(
for: #selector(self.mouseMoved(with:)),
with: event
)
}
Sadly my original version of this post was too long, so I had to cut out the swizzling details, however, I put the whole thing on GitHub, with the complete source code, so you can look at it more in depth. I've never reached the length limit before.
So skipping to the end...
That puts everything in place (or would do if I could have posted the whole thing here), so now you just have to use it.
I was just using Xcode's default Cocoa App template to implement, so it uses a Storyboard (which normally I prefer not to). I just added an ordinary NSButton in the Storyboard. That means I don't start with a reference to it anywhere in the source code, so in ViewController, for the sake of building an example I just do a quick recursive search through the view hierarchy looking for an NSButton.
func findPushButton(in view: NSView) -> NSButton?
{
if let button = view as? NSButton { return button }
for subview in view.subviews
{
if let button = findPushButton(in: subview) {
return button
}
}
return nil
}
And I need to make a tool tip view. I wanted to demonstrate using more than just text, so I hacked this together
func makeCustomToolTip() -> NSView
{
let titleText = "Custom Tool Tip"
let bodyText = "\n\tThis demonstrates that its possible,\n\tand if I can do it, so you can you"
let titleFont = NSFont.systemFont(ofSize: 14, weight: .bold)
let title = NSAttributedString(
string: titleText,
attributes: [.font: titleFont]
)
let bodyFont = NSFont.systemFont(ofSize: 10)
let body = NSAttributedString(
string: bodyText,
attributes: [.font: bodyFont]
)
let attrStr = NSMutableAttributedString(attributedString: title)
attrStr.append(body)
let label = NSTextField(labelWithAttributedString: attrStr)
let imageView = NSImageView(frame: CGRect(origin: .zero, size: CGSize(width: label.frame.height, height: label.frame.height)))
imageView.image = #imageLiteral(resourceName: "Swift_logo")
let toolTipView = NSView(
frame: CGRect(
origin: .zero,
size: CGSize(
width: imageView.frame.width + label.frame.width + 15,
height: imageView.frame.height + 10
)
)
)
imageView.frame.origin.x += 5
imageView.frame.origin.y += 5
toolTipView.addSubview(imageView)
label.frame.origin.x += imageView.frame.maxX + 5
label.frame.origin.y += 5
toolTipView.addSubview(label)
return toolTipView
}
And then in viewDidLoad()
override func viewDidLoad()
{
super.viewDidLoad()
findPushButton(in: view)?.customToolTip = makeCustomToolTip()
}
This problem is caused by user interface interactions such as showing the titlebar while in fullsreen. That question's answer provides a solution, but not how to implement that solution.
The solution is to render on a background thread. The issue is, the code provided in Apple's is made to cover a lot of content so most of it will extraneous code, so even if I could understand it, it isn't feasible to use Apple's code. And I can't understand it so it just plain isn't an option. How would I make a simple Swift Metal game use a background thread being as concise as possible?
Take this, for example:
class ViewController: NSViewController {
var MetalView: MTKView {
return view as! MTKView
}
var Device: MTLDevice = MTLCreateSystemDefaultDevice()!
override func viewDidLoad() {
super.viewDidLoad()
MetalView.delegate = self
MetalView.device = Device
MetalView.colorPixelFormat = .bgra8Unorm_srgb
Device = MetalView.device
//setup code
}
}
extension ViewController: MTKViewDelegate {
func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
}
func draw(in view: MTKView) {
//drawing code
}
}
That is the start of a basic Metal game. What would that code look like, if it were rendering on a background thread?
To fix that bug when showing the titlebar in Metal, I need to render it on a background thread. Well, how do I render it on a background thread?
I've noticed this answer suggests to manually redraw it 60 times a second. Presumably using a loop that is on a background thread? But that seems... not a clean way to fix it. Is there a cleaner way?
The main trick in getting this to work seems to be setting up the CVDisplayLink. This is awkward in Swift, but doable. After some work I was able to modify the "Game" template in Xcode to use a custom view backed by CAMetalLayer instead of MTKView, and a CVDisplayLink to render in the background, as suggested in the sample code you linked — see below.
Edit Oct 22:
The approach mentioned in this thread seems to work just fine: still using an MTKView, but drawing it manually from the display link callback. Specifically I was able to follow these steps:
Create a new macOS Game project in Xcode.
Modify GameViewController to add a CVDisplayLink, similar to below (see this question for more on using CVDisplayLink from Swift). Start the display link in viewWillAppear and stop it in viewWillDisappear.
Set mtkView.isPaused = true in viewDidLoad to disable automatic rendering, and instead explicitly call mtkView.draw() from the display link callback.
The full content of my modified GameViewController.swift is available here.
I didn't review the Renderer class for thread safety, so I can't be sure no more changes are required, but this should get you up and running.
Older implementation with CAMetalLayer instead of MTKView:
This is just a proof of concept and I can't guarantee it's the best way to do everything. You might find these articles helpful too:
I didn't try this idea, but given how much convenience MTKView generally provides over CAMetalLayer, it might be worth giving it a shot:
https://developer.apple.com/forums/thread/89241?answerId=268384022#268384022
Is drawing to an MTKView or CAMetalLayer required to take place on the main thread? and https://developer.apple.com/documentation/quartzcore/cametallayer/1478157-presentswithtransaction
class MyMetalView: NSView {
var displayLink: CVDisplayLink?
var metalLayer: CAMetalLayer!
override init(frame frameRect: NSRect) {
super.init(frame: frameRect)
setupMetalLayer()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
setupMetalLayer()
}
override func makeBackingLayer() -> CALayer {
return CAMetalLayer()
}
func setupMetalLayer() {
wantsLayer = true
metalLayer = layer as! CAMetalLayer?
metalLayer.device = MTLCreateSystemDefaultDevice()!
// ...other configuration of the metalLayer...
}
// handle display link callback at 60fps
static let _outputCallback: CVDisplayLinkOutputCallback = { (displayLink, inNow, inOutputTime, flagsIn, flagsOut, context) -> CVReturn in
// convert opaque context pointer back into a reference to our view
let view = Unmanaged<MyMetalView>.fromOpaque(context!).takeUnretainedValue()
/*** render something into view.metalLayer here! ***/
return kCVReturnSuccess
}
override func viewDidMoveToWindow() {
super.viewDidMoveToWindow()
guard CVDisplayLinkCreateWithActiveCGDisplays(&displayLink) == kCVReturnSuccess,
let displayLink = displayLink
else {
fatalError("unable to create display link")
}
// pass a reference to this view as an opaque pointer
guard CVDisplayLinkSetOutputCallback(displayLink, MyMetalView._outputCallback, Unmanaged<MyMetalView>.passUnretained(self).toOpaque()) == kCVReturnSuccess else {
fatalError("unable to configure output callback")
}
guard CVDisplayLinkStart(displayLink) == kCVReturnSuccess else {
fatalError("unable to start display link")
}
}
deinit {
if let displayLink = displayLink {
CVDisplayLinkStop(displayLink)
}
}
}
I would like to draw CGImage pictures directly to a View and with the normal method using the draw func I only get 7 pictures in a second on a new Mac Book Pro. So I decided to use the updateLayer func instead. I have defined wantsUpdateLayer = true and my new updateLayer func is called as expected. But then starts my problem. When using the draw func, I get the current CGContext with "NSGraphicsContext.current?.cgContext" but in my updateLayer func the "NSGraphicsContext.current?.cgContext" is nil. So I do not know where to put my CGImage, that it will be displayed on my screen. Also "self.view?.window?.graphicsContext?.cgContext" and "self.window?.graphicsContext?.cgContext" are nil, too. There are no buttons or other elements in this view and in the window of the view, only one picture, filling the complete window. And this picture must change 30 times in a second. Generating the pictures is done by a separate thread and needs about 1 millisecond for a picture. I think that from "outside" the NSView class it is not possible to write the picture but my updateLayer func is inside the class.
Here is what the func looks like actually:
override func updateLayer ()
{
let updateRect: NSRect = NSRect(x: 0.0, y: 0.0, width: 1120.0, height: 768.0)
let context1 = self.view?.window?.graphicsContext?.cgContext
let context2 = self.window?.graphicsContext?.cgContext
let context3 = NSGraphicsContext.current?.cgContext
}
And all three contexts are nil in the time the function is called automatically after I set the needsDisplay flag.
Any ideas where to draw my CGImages?
The updateLayer func is called automatically by the user interface. I do not call it manually. It is called by the view. My problem is where inside this method to put my picture to be shown on the screen. Perhaps I have to add a layer or use a default layer of the view but I do not know how to do this.
Meanwhile I have found the solution with some tipps from a good friend:
override var wantsUpdateLayer: Bool
{
return (true)
}
override func updateLayer ()
{
let cgimage: CGImage? = picture // Here comes the picture
if cgimage != nil
{
let nsimage: NSImage? = NSImage(cgImage: cgimage!, size: NSZeroSize)
if nsimage != nil
{
let desiredScaleFactor: CGFloat? = self.window?.backingScaleFactor
if desiredScaleFactor != nil
{
let actualScaleFactor: CGFloat? = nsimage!.recommendedLayerContentsScale(desiredScaleFactor!)
if actualScaleFactor != nil
{
self.layer!.contents = nsimage!.layerContents(forContentsScale: actualScaleFactor!)
self.layer!.contentsScale = actualScaleFactor!
}
}
}
}
}
This is the way to directly write into the layer. Depending on the format (CGImage or NSImage) you first must convert it. As soon as the func wantsUpdateLayer returns a true, the func updateLayer() is used instead of the func draw(). Thats all.
For all who want to see my "Normal" draw function:
override func draw (_ updateRect: NSRect)
{
let cgimage: CGImage? = picture // Here comes the picture
if cgimage != nil
{
if #available(macOS 10.10, *)
{
NSGraphicsContext.current?.cgContext.draw(cgimage!, in: updateRect)
}
}
else
{
super.draw(updateRect)
}
}
The additional speed is 2 times or more, depending on what hardware you use. On a modern Mac Pro there is only a little bit more speed but on a modern Mac Book Pro you will get 10 times or more speed. This works with Mojave 10.14.6 and Catalina 10.15.6. I did not test it with older macOS versions. The "Normal" draw function works with 10.10.6 to 10.15.6.
Here is the situation. I have a protocol, and extension of it.
protocol CustomViewAddable {
var aView: UIView { get }
var bView: UIView { get }
func setupCustomView()
}
extension CustomViewAddable where Self: UIViewController {
var aView: UIView {
let _aView = UIView()
_aView.frame = self.view.bounds
_aView.backgroundColor = .grey
// this is for me to observe how many times this aView init.
print("aView: \(_aView)")
return _aView
}
var bView: UIView {
let _bView = UIView(frame: CGRect(x: 30, y: 30, width: 30, height: 30))
_bView.backgroundColor = .yellow
return _bView
}
func setupCustomView() {
view.addSubview(aView);
aView.addSubview(bView);
}
}
And I make a ViewController to conform this protocol then I add this custom 'aView' to my ViewController's view.
class MyVC: UIViewController, CustomViewAddable {
override func viewDidLoad() {
super.viewDidLoad()
setupCustomView()
}
}
I run it. In my console log it prints twice of init and I trying to do something in my custom 'aView' and it failed. (The code I paste above that I simplified so that it'll be very easy to show my intension)
Could anybody to explain why or make a fix to it that I'll be very appreciated.
Because your var aView: UIView is computed variable not store variable,
So every time you call aView, it will create a new UIView,
You can use Associated Objects in NSObject here is some tutorials:
swift-objc-runtime
associated-objects
Hope this may help.
Basically in the way you implemented the setupCustomView method nothing should work because as mentioned in another response you're using a computed property, so this implies that every time you access the property it's created again.
You don't need to use associated-objects or something like that to achieve what you want, you only need to keep the reference of the aView at the beginning avoiding calling it again, in this way:
func setupCustomView() {
let tView = aView // only is computed once
view.addSubview(tView)
tView.addSubview(bView)
}
I hope this help you.