I am trying to build a view in SwiftUI that allows me to draw on top of another view, for example a table, using PencilKit. Everything must be zoomable and the elements of the background view must be clickable.
I thought about using a ZStack:
ZStack {
CanvasView(canvasView: $canvasView)
BackgroundView()
}
In this way I can draw on top of the BackgroundView and interact with its elements, but how can I manage the zoom? When I zoom only the canvas scales itself.
I thought about using scrollViewDidZoom:
extension Coordinator: PKCanvasViewDelegate {
func scrollViewDidZoom(_ scrollView: UIScrollView) {
onZoom()
}
}
To know when the Canvas is zooming. Then the SwiftUI View change as below:
ZStack {
CanvasView(canvasView: $canvasView, onZoom: onZoom)
BackgroundView()
.scaleEffect(scale)
}
func onZoom() {
scale = canvasView.zoomScale
}
This way the BackgroundView scales itself but only focusing on the center.
Is there a way to follow not only the canvas zoom scale but also the anchor of the zoom?
Or more generally, is there a way to get what I want?
I see many apps that permits to draw on top of some view and interact with buttons inside that view, but I cannot find any useful documentation about that.
Thank you
Related
I have a UIViewRepresentable that I am using the blend a project created with UIViews and SwiftUI.
My views are full screen and my issue is that I cannot find a way to pass touches through the transparent UINavigationBar at the top of the screen to my underlying UIView. That means that the top 100 or so pixels don't respond to touch even though they're visible. I have seen this post and solution, but it does not work in my case. I believe it's because I'm using UIViewRepresentable.
For my content view I have:
struct ContentView: View {
let values: [String] = ViewType.allCases.map { "\($0.rawValue)" }
var body: some View {
NavigationView {
List {
ForEach(values, id: \.self) { value in
NavigationLink(value, destination: CustomView(viewName: value).ignoresSafeArea())
}
.navigationTitle("Nav Title")
}
}
.accentColor(.white)
}
}
struct CustomView: UIViewRepresentable {
let viewType: String
func makeUIView(context: Context) -> CustomView {
CustomView(view: viewType)
}
func updateUIView(_ view: CustomView, context: Context) {
view.draw(view.frame)
}
}
Here is an image of my view hierarchy that shows the UINavigationBar blocking the top 100 or so pixels of my underlying UIView and preventing touches from being registered by the view.
I know I can disable the navigation bar and that does work, but I do need the back button. Ideally, I'd like to understand how I can apply the solution I linked to above which will pass touches unless there is a UIControl in the way.
UPDATE
I tried Asperi's suggestion of using transparency and then disabling the navigation bar and it occurred to me to check the view debugger with it disabled.
It turns out that the back button is still there in the view hierarchy, but it is not visible in the app when the nav bar is disabled. If there were a way to keep the nav bar disabled but enable the button, that would be the ideal situation.
I have a ZStack containing 2 views:
referenceContent - has some content and a Divider. This is the main content across the screen
popoverContent - is a conditional popup window that only takes up a tiny portion of the screen.
var body: some View {
ZStack {
referenceContent
if popoverCondition {
popoverContent
}
}
}
I want the popoverContent's top edge to line up with the bottom of referenceContent
Anyone know how to make this happen? Or is there just a much better way to view this popup window than I'm doing now? Thanks!
You can do this using the overlay(alignment:content:) modifier (previously overlay(_:alignment:)) in combination with custom alignment guides.
The basic idea is that you align the bottom of your reference view with the top of your popover view.
The annoying thing is that the overlay modifier only lets you specify one alignment guide (for the two views). So if you write stack1.overlay(alignment: .bottom) { stack2 } it will align the bottom of your reference with the bottom of your overlay. A quick way to overcome this is to overwrite the bottom alignment guide of your overlay and return the top instead.
referenceView
.overlay(alignment: .bottom) {
popoverContent
// overwrites bottom alignment of the popover with its top alignment guide.
.alignmentGuide(.bottom) {$0[.top]}
}
Overlay vs ZStack
You might ask: "why don't you use a ZStack instead of an overlay?". Well the difference between the two is that the ZStack will take the size of your popover into consideration when laying out your entire view (reference + popover). That is the opposite of what a popover should do. For a popover, the layout system should only take the size of your reference view into consideration and draw the popover on top of it (without affecting the layout of your reference). That is exactly what the overlay(...) modifier does.
Old API (prior to iOS 15, macOS 12)
In older versions of SwiftUI the arguments of the overlay modifier were in reverse order. So the code example for these older systems is:
referenceView
.overlay(
popoverContent.alignmentGuide(.bottom) {$0[.top]},
alignment: .bottom
)
Custom alignment guides
When you don't want to overwrite an existing alignment guide (because you need it somewhere else for example) you can also use a custom alignment guide. Here is a more generic example using a custom alignment guide named Alignment.TwoSided
extension View {
#available(iOS 15.0, *)
func overlay<Target: View>(align originAlignment: Alignment, to targetAlignment: Alignment, of target: Target) -> some View {
let hGuide = HorizontalAlignment(Alignment.TwoSided.self)
let vGuide = VerticalAlignment(Alignment.TwoSided.self)
return alignmentGuide(hGuide) {$0[originAlignment.horizontal]}
.alignmentGuide(vGuide) {$0[originAlignment.vertical]}
.overlay(alignment: Alignment(horizontal: hGuide, vertical: vGuide)) {
target
.alignmentGuide(hGuide) {$0[targetAlignment.horizontal]}
.alignmentGuide(vGuide) {$0[targetAlignment.vertical]}
}
}
}
extension Alignment {
enum TwoSided: AlignmentID {
static func defaultValue(in context: ViewDimensions) -> CGFloat { 0 }
}
}
You would use that like this:
referenceView
.overlay(align: .bottom, to: .top, of: popoverContent)
I have a form in a Mac app that needs to scroll. I have a scrollView embedded in a ViewController. I have the scrollView assigned with an identifier that links it to its own NSScrollView file. The constraints are set to the top, right, and left of the view controller, it also has the hight constraint set to the full height of the ViewController.
Here is my code:
import Cocoa
class ScrollView: NSScrollView {
override func draw(_ dirtyRect: NSRect) {
super.draw(dirtyRect)
// Drawing code here.
NSRect documentView.NSMakeSize(0, 0, 1058.width, 1232.height)
}
override func scrollWheel(with event: NSEvent) {
switch event.phase {
case NSEvent.Phase.began:
Swift.print("Began")
// case NSEvent.Phase.changed:
// Swift.print("Changed")
case NSEvent.Phase.ended:
Swift.print("Ended")
default:
break
}
switch event.momentumPhase {
case NSEvent.Phase.began:
Swift.print("Momentum Began")
// case NSEvent.Phase.changed:
// Swift.print("Momentum Changed")
case NSEvent.Phase.ended:
Swift.print("Momentum Ended")
default:
break
}
super.scrollWheel(with: event)
}
I cant seem to get my app to scroll at all. I think I am not setting the frame correctly. What is the best way to do set the frame correctly? Am I coding the NSScrollView correctly?
I think you are making your life very hard because you are doing things that are not exactly recommended by Apple. First of all, you should not subclass NSScrollView. Rather you should read first Introduction to Scroll View Programming Guide for Cocoa by Apple to understand how you should create the correct hierarchy of views for an NSScrollView to work correctly.
A second recommendation is for you to check this nice article about how you should set up an NSScrollView in a playground, so that you can play with the code you want to implement.
Third, using Autolayout and NSScrollView has caused a lot of grief to a lot of people. You need to set up the AutoLayout just right, so that everything is going to work as expected. I recommend that you check this answer by Ken Thomases, which clearly explains how you need to set up auto layout constraints for an NSScrollView to work properly.
I just got over the "hump" with a NSScrollView inside a NSWindow. In order for scrolling to occur the view inside the NSScrollview needs to be larger than the content window. That's hard to set with dynamic constraints. Statically setting the inner view to a larger width/height than the window "works" but the static sizes usually are not what you want.
Here is my interface builder view hierarchy and constraints, not including the programmatically added boxes
In my app the user is adding "boxes" (custom draggable views) inside the mainView, which is inside a scrollview in a NSwindow.
Here's the functionality I wanted:
If I expanded the NSWindow, I wanted the mainView inside the scrollview to expand to fill the whole window. No scrolling needed in this case if all the boxes are visible.
If I shrank the NSWindow, I wanted the mainView inside the scrollview to shrink just enough to include all my mainView subviews ("boxes"), but not any further (i added a minBorder of 20). This results in scrolling if a box's position is further right/up than the nswindow's width/height.
I found the trick is to calculate the size of the mainView I want based on the max corner of each draggable boxview, or the height/width of the content frame of the nswindow, whichever is larger.
Below is my code, including some debugging prints.
Be careful of which subviews you use to calculate the max size. If you include a subview that's dynamically attached to the right/top of the window, then your window will never shrink. If you add +20 border to that, you might infinite loop. Not a problem in my case.
extension MapWindowController: NSWindowDelegate {
func windowDidEndLiveResize(_ notification: Notification) {
if let frame = window?.frame, let content = window?.contentRect(forFrameRect: frame) {
print("window did resize \(frame)")
var maxX: CGFloat = content.width
var maxY: CGFloat = content.height
for view in mainView?.subviews ?? [] {
let frameMaxX = view.frame.maxX + minBorder
let frameMaxY = view.frame.maxY + minBorder
if frameMaxX > maxX {
maxX = frameMaxX
}
if frameMaxY > maxY {
maxY = frameMaxY
}
}
print("view maxX \(maxX) maxY \(maxY)")
print("window width \(content.width) height \(content.height)")
mainView?.setFrameSize(NSSize(width: maxX, height: maxY))
}
}
}
I have an UIStackView build in interface builder which changes it's axis property from vertical to horizontal when it's superview rotates from portrait to landscape. The issue is that this results in an animation of it's two arranged subviews, where one of those views overlaps the other view while transitioning to the new position.
In my case I would like to remove only that particular animation and force the view to it's end position right away.
I have tried to remove all animation on from the stackview layer in my VC:
public override func willTransition(to newCollection: UITraitCollection,
with coordinator: UIViewControllerTransitionCoordinator) {
coordinator.animate(alongsideTransition: {
_ in
// The first subview is `UIStackView`
self.view.subviews[0].layer.removeAllAnimations()
})
super.willTransition(to: newCollection, with: coordinator)
}
And I observed the animation keys when the axis property is changed, because that seems to happen somewhere during the transition (set automatically by interface builder). Unfortunately I had no luck with it, because the layer returns nil for animationKeys on the stackview and its subviews/arrangedSubviews.
class StackView : UIStackView {
override var axis: UILayoutConstraintAxis {
didSet { /* here */ }
}
}
That's going to be challenging, I think. There's a nice demo of what it sounds like you're trying to do over here if the axis animation it shows is what you're trying to get rid of, pretty sure that's outside the UIStackView design space.
Pretty sure the best solution to "force the view to it's end position right away" is to in fact have one UIStackView for each axis and move the contents between them on rotation.
You could also try putting a performWithoutAnimation block in your viewWillTransition(to:with:) that calls updateConstraintsIfNeeded on completion? Maybe that would work. I'd go with the two-view idea instead of that though!
Is there a way I can set my scrollview not to clip its contents? (Which is a NSTextView)
I have a subclass of NSScrollView and want its content not to be clipped to its bounds.
I have tried overriding:
- (BOOL) wantsDefaultClipping{
return NO;
}
in MyScrollView and in MytextView without any effect.
In the iOS I would simply would do: myuitextView.clipsToBounds=NO; how can I do this in Cocoa?
EDIT
This is an example of what I want to achieve but in the mac
The scrollview is white, the scroller will never go outside its bounds but the text does since I did myuitextView.clipsToBounds=NO
See picture here
EDIT2
I wouldn't mind clip my view like #Josh suggested. But the real behaviour I would like to have can be explained with this picture:
Do you see the word *****EDIT***** that has being cut in the very first line?
I want the text not to be cut this way, rather I want it to completely appear and I will put a semitransparent image so it looks like it fades off when it's outside the frame.
Q: Why don't I simply put a semitransparent NSImageView on it so it looks like what I want?
A: Because 1.Scroller will be faded as well. Even if I correctly place the semitransparent NSImageView so the scroller looks fine, the cursor/caret will be able to go underneath the semitransparent NSImageView again it does not look good.
I would like to be able to control the area is clipped by NSClipView. I think that would solve my problem. Is there any alternative I have? maybe I can control the caret position or scrolling position through NSTextView so caret will never go near the top/bottom frame limits? or any work-around?
Any advice is appreciated.
Now that it's 2016 and we're using vibrant titlebars with full size content views, I'll add my thoughts to how someone might accomplish this. Hopefully, this will help anyone who came here looking for help on this, as it helped me.
This answers the question in regards to scrolling under the titlebar, but you could easily modify this technique to scroll under other things using the insets and caret position.
To get a scroll view (with or without an NSTextView inside of it) to scroll behind a titlebar, you can use:
// For transparent title.
window.titlebarAppearsTransparent = true
window.styleMask = window.styleMask | NSFullSizeContentViewWindowMask
window.appearance = NSAppearance(named: NSAppearanceNameVibrantLight)
This effectively overlays the titlebar of the NSWindow onto the window's contentView.
To constrain something to the top of the window without knowing the height of the titlebar:
// Make a constraint for SOMEVIEW to the top layout guide of the window:
let topEdgeConstraint = NSLayoutConstraint(
item: SOMEVIEW, attribute: NSLayoutAttribute.Top,
relatedBy: NSLayoutRelation.Equal,
toItem: window.contentLayoutGuide,
attribute: NSLayoutAttribute.Top, multiplier: 1.0, constant: 0.0)
// Turn the constraint on automatically:
topEdgeConstraint.active = true
This allows you to constrain the top of an element to the bottom of the titlebar (and or toolbar + any accessory views it may have). This was shown at WWDC in 2015: https://developer.apple.com/videos/play/wwdc2014/220/
To get the scrollview to scroll under the titlebar but show its scrollbars inside the unobscured part of the window, pin it to the top of the content view in IB or via code, which will cause it to be under the titlebar. Then, tell it to automatically update it's insets:
scrollView.automaticallyAdjustsContentInsets = true
Finally, you can subclass your window and handle the cursor/caret position. There is a presumed bug (or developer error on my part) that doesn't make the scrollview always scroll to the cursor/caret when it goes above or below the content insets of the scrollview.
To fix this, you must manually find the caret position and scroll to see it when the selection changes. Forgive my awful code, but it seems to get the job done. This code belongs in an NSWindow subclass, so self is referring to the window.
// MARK: NSTextViewDelegate
func textViewDidChangeSelection(notification: NSNotification) {
scrollIfCaretIsObscured()
textView.needsDisplay = true // Prevents a selection rendering glitch from sticking around
}
// MARK: My Scrolling Functions
func scrollIfCaretIsObscured() {
let rect = caretRectInWindow()
let y: CGFloat = caretYPositionInWindow() - rect.height
// Todo: Make this consider the text view's ruler height, if present:
let tbHeight: CGFloat
if textView.rulerVisible {
// Ruler is shown:
tbHeight = (try! titlebarHeight()) + textViewRulerHeight
} else {
// Ruler is hidden
tbHeight = try! titlebarHeight()
}
if y <= tbHeight {
scrollToCursor()
}
}
func caretYPositionInWindow() -> CGFloat {
let caretRectInWin: NSRect = caretRectInWindow()
let caretYPosInWin: CGFloat = self.contentView!.frame.height - caretRectInWin.origin.y
return caretYPosInWin
}
func caretRectInWindow() -> CGRect {
// My own version of something based off of an old, outdated
// answer on stack overflow.
// Credit: http://stackoverflow.com/questions/6948914/nspopover-below-caret-in-nstextview
let caretRect: NSRect = textView.firstRectForCharacterRange(textView.selectedRange(), actualRange: nil)
let caretRectInWin: NSRect = self.convertRectFromScreen(caretRect)
return caretRectInWin
}
/// Scrolls to the current caret position inside the text view.
/// - Parameter textView: The specified text view to work with.
func scrollToCursor() {
let caretRectInScreenCoords = textView.firstRectForCharacterRange(textView.selectedRange(), actualRange: nil)
let caretRectInWindowCoords = self.convertRectFromScreen(caretRectInScreenCoords)
let caretRectInTextView = textView.convertRect(caretRectInWindowCoords, fromView: nil)
textView.scrollRectToVisible(caretRectInTextView)
}
enum WindowErrors: ErrorType {
case CannotFindTitlebarHeight
}
/// Calculates the combined height of the titlebar and toolbar.
/// Don't try this at home.
func titlebarHeight() throws -> CGFloat {
// Try the official way first:
if self.titlebarAccessoryViewControllers.count > 0 {
let textViewInspectorBar = self.titlebarAccessoryViewControllers[0].view
if let titlebarAccessoryClipView = textViewInspectorBar.superview {
if let view = titlebarAccessoryClipView.superview {
if let titleBarView = view.superview {
let titleBarHeight: CGFloat = titleBarView.frame.height
return titleBarHeight
}
}
}
}
throw WindowErrors.CannotFindTitlebarHeight
}
Hope this helps!
I would simply try to observe the document view's frame and match the scroll view's frame when the document resizes.
This is a little hairy. AFAIK, NSViews can't draw outside their own frame. At any rate I've never seen it done, and I was somewhat surprised when I realized that UIView allows it by default. But what you probably want to do here is not manipulate clipping rectangles (doing any such thing inside NSScrollView will probably not do what you want or expect), but instead try to cover up the vertically-truncated text lines with either layers or views that are the same color as the background. Perhaps you could subclass NSClipView and override viewBoundsChanged: and/or viewFrameChanged: in order to notice when the text view is being shifted, and adjust your "shades" accordingly.
You might consider using a translucent layer to achieve this appearance, without actually drawing outside your view. I'm not certain of the rules on iOS, but on the Mac, a view drawing outside its bounds can cause interference with surrounding drawing.
However, you can set the clipping region to be whatever you like inside your scroll view subclass's drawRect: using -[NSBezierPath setClip:]:
- (void)drawRect:(NSRect)dirtyRect {
[NSGraphicsContext saveGraphicsState];
[[NSBezierPath bezierPathWithRect:[[self documentView] frame]] setClip];
//...
[NSGraphicsContext restoreGraphicsState];
}
It might be possible (since you asked) to use this code in an NSClipView subclass, but there's not much info about that, and I think you may have a hard time making it interact properly with its scroll view. If it were me, I'd try subclassing NSScrollView first.