Is there any way to obtain a flash screen effect like the one produced when a screenshot is taken, on demand, for a certain NSView? My question is not a duplicate of flashing screen programatically with Swift (on 'screenshot taken') , since I need a solution for osx, not ios and the methods are different.
Something like this might work
func showScreenshotEffect() {
let snapshotView = UIView()
snapshotView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(snapshotView)
// Activate full screen constraints
let constraints:[NSLayoutConstraint] = [
snapshotView.topAnchor.constraint(equalTo: view.topAnchor),
snapshotView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
snapshotView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
snapshotView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
]
NSLayoutConstraint.activate(constraints)
// White because it's the brightest color
snapshotView.backgroundColor = UIColor.white
// Animate the alpha to 0 to simulate flash
UIView.animate(withDuration: 0.2, animations: {
snapshotView.alpha = 0
}) { _ in
// Once animation completed, remove it from view.
snapshotView.removeFromSuperview()
}
}
The way to achieve this is to create a new UIView that is the same size of the screen, and black in color, add it a subview of your view then animate the alpha to zero( play around with the duration to achieve the desired effect) after completion remove the view from superview.
I have used this technique in many of my projects and it works like a charm. You can play around with the background color of the view to customize the look of the flash.
Related
Hi this is a more general question on how to approach this.
As you can see in the image below I have 4 textLabels in a stack view, and behind the stack view is a red UIVew.
When the UIView slides over the next text, I would like the text to change color whenever the view is over the text.
I don't want an abrupt change, but rather a masking/sliding color effect, driven by the red UIView.
Currently its only changing colours once the transition is done.
How would you approach this?
on request the basic sliding code:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if isScrolling {
let factor = (scrollView.contentOffset.x/UIScreen.main.bounds.width) * (margin.left/2)
self.navigationBar.indicatorConstraint.constant = (scrollView.contentOffset.x / 4) - factor
}
}
It is possible to achieve but it is not straight forward.
You would have to add white and black text UILabels. These labels contained on a view, for example the WhiteLabelsView and the BlackLabelsView. The red view should mask the WhiteLabelsView, and the BlackLabelsView should be behind them.
Your view should look like this (RedView is the top most view):
[ RedView ]
[ WhiteLabelsView ]
[ BlackLabelsView ]
I know it may sound a little bit of a drag to ask this question but I am curious if anything like this is available.
I am building a app in which the background image (covers full view with a blur effect) of each view controller changes dynamically. This background image will be in all the view controllers, each one having a different set of UIControls (Labels, Buttons, Table Views, Collection Views, containers, tabs, etc).
Sometimes when the background image is very light, the foreground texts (labels, buttons) with white text colour are not visible at all. Also the vice versa is a problem too.
So I would like to know if there is any way to change the foreground text colour dynamically based on its background.
Recently I faced the same problem, And I think what you looking for is either image is bright or dark so that you can set property accordingly Hope this will help.
Create observer, everytime image change it will check if its a dark image or bright and based on that will call the function UIForDarkImage and UIForBrightImage
//ImageView observer to observe the image change and perform the UI action based on the image colour
//Your imageView you are using to set image
var imageView: UIImageView {
didSet {
if imageView.isDark(image.bounds) { //dont pass the full image bounds pass the rect where your buttons or label places it will save your hell lot of time
setUIForDarkImage() // here you set buttons and labels color to white or whatever changes you want to perform based dark image
}
else {
setUIForBrightImage() // here you set buttons and labels color to black or whatever changes you want to perform based bright image
}
}
}
UIImageViewExtension for checking if Image is a dark image or bright Image.
What happening is, It will go through image pixel-by-pixel and check if the pixel is bright or dark and if we get dark pixels more than the threshold we have set, we will assuming that its a dark image else it's a bright image.
PS: For better efficiency not checking the whole image (for a high-resolution image it will slow down if we will check all pixels) so only checking the part of the image in which we need our button or label, you can set rect based on your requirement. And also scaling by 0.45 to check few pixels in that rect(you can increase or decrease for more/less accuracy).
extension UIImageView {
func isDark(_ rect:CGRect)->Bool {
let s=image?.cgImage?.cropping(to: rect);
let data=s?.dataProvider?.data;
if data == nil {return false;}
guard let ptr = CFDataGetBytePtr(data) else {return false;}
let threshold = Int(Double(rect.width * rect.height) * 0.45);
var dark = 0,len=CFDataGetLength(data);
for i in stride(from: 0, to: len, by: 4) {
let r = ptr[i], g = ptr[i+1], b = ptr[i+2];
if (0.299 * Double(r) + 0.587 * Double(g) + 0.114 * Double(b)) < 100 {dark += 1;}
if dark > threshold {return true;}
}
return false;
}
}
PS: If you also like to know what I am doing in setUIForBrightImage() and setUIForDarkImage do let me know
Here's what I would do: Create a struct that contains the name of the image view and a tint color to use for your labels, buttons, etc.
Add a property to your view controllers using this new struct. Let's call it backgroundImageSettings.
Add a didSet method to the property that calls another method useBackgroundImageSettings() that installs the image into the background of the view controller's content view, sets the tint color for the view controller's content view, and calls setNeedsDisplay() on the content view.. Also call useBackgroundImageSettings() in your viewDidLoad so that setting your backgroundImageSettings still works even if you view controller's view hasn't been loaded yet.
I like Duncan's answer! An additional step you can take is to set a slight overlay onto your background image.
For example, if you have a background image with really dark colors and you can't see your black text very well, then you can add a layer with a background color of white and an opacity less than 1. That way there's a bit of white to make your text more readable, and you can still see the background image.
let overlay = UIView(frame: yourSuperView.bounds)
overlay.backgroundColor = UIColor.white
overlay.layer.opacity = 0.5
yourSuperView.addSubview(overlay)
I am implementing a popover view using UIPopoverPresentationController.
The trouble with this, is that by default, I have a shadow with a large radius for the controller.
I want to disable this - the overlay.
I have tried:
to customise the layout shadow (using a UIPopoverBackgroundView):
layer.shadowColor = UIColor.white.withAlphaComponent(0.01).cgColor
layer.shadowOffset = .zero
layer.shadowRadius = 0
In view debugging - I can see behind the popup 4 image views with gray gradient background:
I am sure this is a default behaviour, of showing an overlay behind a popover.
How do disable this?
I found this and this. But those didn't helped.
If you take a closer look at the views hierarchy you will notice that the shadow layer _UIMirrorNinePatchView is a sublayer of UITransitionView same as UIPopoverView - both are on the same level.
views hierarchy picture
In this case you can try to hide this sublayer like so:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
if let shadowLayer = UIApplication.shared.windows.first?.layer.sublayers?[1].sublayers?[1] {
shadowLayer.isHidden = true
}
}
Make sure to hide it in viewDidLayoutSubviews to avoid exceptions related to missing sublayers or sublayer flickering.
I am wanting to make a round UIButton but with a light blur effect with vibrancy as it's background
So far I've got a rounded UIButton, but the code I have found online (I'm new to iOS development so don't really understand how the blur etc works) to add a blur just puts it as the entire button's frame, essentially making the button appear square again.
I've also tried adding a view, then the UIButton and then the blur effect and applied the cornerRadius code to that view but it also didn't work.
Here is what I've tried:
shortcutButton.layer.cornerRadius = 0.5 * shortcutButton.bounds.size.width // add the round corners in proportion to the button size
let blur = UIVisualEffectView(effect: UIBlurEffect(style:
UIBlurEffectStyle.Light))
blur.frame = shortcutButton.bounds
blur.userInteractionEnabled = false //This allows touches to forward to the button.
shortcutButton.insertSubview(blur, atIndex: 0)
Add the following two lines of code to your project, before you add the subview:
blur.layer.cornerRadius = 0.5 * shortcutButton.bounds.size.width
blur.clipsToBounds = true
Enjoy! :)
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.