Adding a NSButton to a CALayer in OS X Cocoa - xcode

I have a layer hosting view containing a CAlayer, displaying in this case a nice blue opaque rectangle. What I want to do is to add a NSButton on top of the layer, so that it sits above and moves with the blue rectangle when it is animated.
My attempt so far is as follows:
in #interface
IBOutlet NSButton* firstButton;
in #implementation
[layer addSublayer:[firstButton layer]];
firstButton.layer.position=NSMakePoint(0, 80.);
This successfully moves the location of the button on screen, but it doesn't move the 'hit target' of the button.
According to the similar question asked here on Apple Mailing Lists the solution seems to be to move the NSButton with a setFrameOrigin: on the button. This doesn't seem to work for me as it changes the position of the displayed button as well as the 'hit target'. I can't seem to move the hit target independently.
Alternatively: Am I going about this all the wrong way? Is there a better way of doing this?

Unfortunately you cannot move buttons (including the hit target) by manipulating their layers. This is highly unfortunate, but you're going to have to use the animator proxy on the frame of the button itself, and not try to modify the layer directly.

Related

NSButtons leave artefacts when used as subviews of a custom toolbar view

I'm placing a few buttons in a simple rectangular NSview which acts as a custom toolbar. On first render the buttons/views come out as expected, but every time a button is pressed (and sometimes with no mouse interaction at all) artefacts start appearing.
Before
After
I can eliminate the artefacts by calling a [self.toolbarView setNeedsDisplay:YES] in all the action and focus methods but this seems like a hack, is there any clean way to deal with this?
It was a beginner's problem. In the drawRect method
- (void)drawRect:(NSRect)dirtyRect
I was using the param dirtyRect for drawing an outline of my view, assuming it was the view's bounds, where in fact it was only the area around the buttons that became dirty when they were pressed. The 'artefacts' were actually my outline being drawn in the wrong place.
By correctly using the bounds of the view
NSRect drawingRect = [self bounds];
the 'artefacts' no longer appeared.
You just try to set focus ring for a buttons to 'none' in IB.

iOS. How Do Enable a Transparent Image to Pass Touches to a UIButton Below it?

For an iPad app I am writing I have a container UIView with two subview that are UIView subclasses:
A UIImageView whose image has a portion of it cut away to reveal what is below it.
A UIButton below the UIImageView that is revealed through the cut away portion of the UIImageView.
Since the UIImageView overlaps the UIButton spatially it is preventing touches from reaching the UIButton even though the UIButon is fully visible due to the alpha matte cutout in the UIImageView. How do I allow the UIImageView to pass touches to it's sibling UIButton?
Thanks,
Doug
UIImageView usually won't block touches, UIViews do.
You can set the userInteractionEnabled property on the overlapping views to NO, then touches should go through them.
An other approach would be writing a custom hitTest that redirects the thouches to the button.
In addition to Bastian's answer it was also necessary for me to uncheck the Opaque drawing attribute in interface builder for my UIImageView
Even with user interaction enabled, which is the default value when placing a UIImageView in Interface Builder, the touches should pass through to your button underneath, even if your image view has a solid background. Something else must be going on like a UIView sitting on top of the button.
If you are trying to do something more complex to get touches to pass through to underlying views or a separate view controller whose view is underneath, I created this simple open source library:
https://github.com/natrosoft/NATouchThroughView
The REAMDE and demo show how to use it.

NSTextView overlay causes oddities with first responder status

I have an NSTextView in an NSScrollView, and I am programmatically inserting an NSView subclass as a subview of the NSTextView. This NSView acts as an overlay, superimposing graphical information about the text beneath it.
I thought it was working quite well until I noticed that the text view does not respond to right clicks. Other operations (editing, selection) seem to work just fine.
Also, if the first responder is changed to a sibling of the scroll view (an outline view, for example) the text view does not regain first responder status from clicking on it. The selection will change in response to clicking, but the selection highlight is gray instead of blue (indicating that the text view is not the first responder).
If I offset the frame of the overlay subview, the text view behaves 100% normally in the area not overlapped by the overlay, but the overlapped area behaves incorrectly, as outlined above.
Steps To Replicate This Behavior on Mac OS X 10.6.4:
Create a plain old non-document-based Cocoa app.
Add an `NSTextView' IBOutlet to the app delegate .h.
Add an NSTextView to the window in MainMenu.xib. Connect the textView outlet.
Type in a bit of code:
In applicationDidFinishLaunching:
NSView *overlay = [[NSView alloc] initWithFrame:textView.bounds];
[textView addSubview:overlay];
[overlay release];
Run the app, observe that right click in the text area does not work as it should, yet you can still otherwise interact with the text view.
Next, add an NSOutlineView to the window in the xib. Observe that once focus leaves the text area (if you click on the outline view) with the overlay in place, you cannot set the focus back to the text view (it will not become first responder again).
Is there some way I can enable the NSTextView to receive all of its events, even though my NSView overlay does not accept first responder or mouse events? I suspect this might be related to the field editor – perhaps it is ignoring events it thinks are destined to the overlay view?
You probably need to make your overlay an instance of a custom view class that forwards all events and accessibility messages to the text view. You may also need to convert any view-relative coordinates to the text view's coordinate system.
I don't have a lot of experience with it, but another possibility would be to use a Core Animation layer as an overlay.
A clean way to handle this is by making your overlay view a custom subclass of NSView, and then overriding the hitTest: method to always return nil. This will prevent the overlay view from participating in the responder chain. Instead, events will get sent automatically to it's superview or views higher up the view hierarchy. You might also want to override acceptsFirstResponder to return NO to be safe (in case it's accidentally set programatically).

NSTextField over NSOpenGLView

I have made a window with an NSOpenGLView that I am rendering openGL content into.
I want to add some buttons and text fields to the view: I can add NSTextFields and NSButtons using interface builder (or code) but they do not appear.
NSOpenGLView is documented as not being able to have sub views, so I then made my own CustomGLView by deriving directly from NSView and implementing the code to create and use a NSOpenGLContext in it. But the subviews are still not appearing :- the OpenGL context paints over them.
On Windows this problem does not exist:- Windows used to host OpenGL MUST have the WS_CLIPCHILDREN and WS_CHIPSIBLINGS styles set ensuring that any peer, or sub children (views) will not be obscured by the OpenGL surface.
How do I get subviews to display over a NSView thats drawing using OpenGL ?
You have 2 choices:
Create a window just for the text field. Add as a child window of the one hosting the OpenGL view. Major downside is you have to manage positioning it correctly if the Open GL view is moved.
Set up your view hierarchy like so:
Layer-backed view
Layer-hosting view whose layer contains an OpenGL layer
Text field
Simply call -setWantsLayer:YES on the subviews of the NSOpenGLView.
NSOpenGLView cannot have subviews according to the documentation. Even if you subclass the NSOpenGLView, that will change nothing.
What you can do is to create a NSView that will hold both the NSOpenGLView and the NSTextField. You then overlap them in the right order to make one draw atop the other.
I'm not heavily into OpenGL yet, but it's my understanding that you can accomplish the visual effect of subviews with Quartz Extreme using layer-backed views; however, those may be problematic. Since subviews are not supported directly, any solution is liable to be a hack.
Indeed, the solution in that link actually hacks a second window to appear over your OpenGL display, the second window displaying the Cocoa views you desire.
The following code (from the above link) is something I've not tested (again not being an OpenGL guy by nature -- yet), but appears like a fairly clever approach:
// This is the GL Window and view you already have
glWindow = [[GLWindow alloc] initWithContentRect:windowRect];
glView = [[[GLView alloc] initWithFrame:NSMakeRect(0, 0, windowRect.size.width, windowRect.size.height)] autorelease];
[glView translateOriginToPoint:NSMakePoint(glView.bounds.size.width/2, glView.bounds.size.height/2)];
[glWindow setContentView:glView];
// And here's your transparent UI window
uiWindow = [[TransparentWindow alloc] initWithContentRect:windowRect];
uiView = [[[NSView alloc] initWithFrame:NSMakeRect(0, 0, windowRect.size.width, windowRect.size.height)] autorelease];
[uiView translateOriginToPoint:NSMakePoint(uiView.bounds.size.width/2, uiView.bounds.size.height/2)];
uiView.wantsLayer = YES;
[uiWindow setContentView:uiView];
[glWindow addChildWindow:uiWindow ordered:NSWindowAbove];
Again, I've not tested this, but it looks like it will get you the visual effect you desire.
The text can be rendered into a texture -- I just used this for a project, did a lot of looking for sample code, and ultimately found Apple's GLString demo code, which was an absolute trove of how-to:
http://developer.apple.com/library/mac/#samplecode/CocoaGL/Listings/GLString_m.html
I haven't tried adding buttons, but you can, of course, draw your own and comparing the positions of click events with those of your buttons...
This was my solution:
1) Create a parent NSView (let's call it parentView).
2) Add an NSOpenGLView Child to parentView.
3) Add an additional NSView Child to parentView (make sure this is after the OpenGLView within the hierarchy). You can add additional TextFields, etc. to this view.
4) In the ViewController for the parent make sure you call [parentView setWantsLayer: TRUE]; I did this within -(void) viewWillAppear
1) The NSOpenGLView can have a subview. It can have plenty even.
2) The reason some views, controls and other elements are being bullied by NSOpenGLView is due to the loading process when the Application launches. I.e If you add a slider or textfield above and into the content view of the window where the NSOpenGLView also resides, upon Application-Launch that textfield will most likely wind up beneath the NSOpenGLView.
This is an Apple Bug. And they know about it.
You can solve it quite easily even without adding a subview to NSOpenGLView...
In Interface Builder drag i.e. a CustomView into the canvas (Not the view). And set it the way you want it with sliders, text and what not. Then create an outlet (Call it i.e topView) in your view controller. Then somewhere in your code... Perhaps (applicationDidFinishLaunching) add this line...
[_window.contentView addSubview:_topView];
(Do your positioning & layout)
This will do the exact same thing as if you had dragged it into the contentView yourself inside IB. Only it will draw the darn thing in the correct Z position.
You loose IB's constraints this way and have to it manually
One could also just subclass and CAOpenGLLayer and use that as a backing layer inside of a regular NSView. There too it is drawn correctly...
Here is Apple's way of wanting to do that. CALayers are a Godsend ;)
Enter following String ** NSOpenGLLayer** in search and hit enter to get to where it is...
NSOpenGLLayer
Hope this helps....

Cocoa: [statusItem setView:myView] makes a white bar menu item no matter what

In my small app for Mac OS X I display some info in system menubar. I use
statusItem = [
[[NSStatusBar systemStatusBar]
statusItemWithLength:NSVariableStatusItemLength]
retain
];
It works very nice and I can change the text with
[statusItem setTitle:[NSString stringWithString:#"Woo-hoo"]];
But it uses the default menu font which is too big for my relatively unimportant info. So I decided to reimplement it with a custom view. I created a view in Interface Builder.
Unfortunately, however, when I set it as a view for my menu item with
[statusItem setView:myView];
it just displays a white bar in the menu instead of my thing. I tried to
[statusItem
drawStatusBarBackgroundInRect:[myView frame]
withHighlight:NO];
with no success.
In trying to figure out whether a problem is with the view itself or with the way I assign it to the menubar, I created a window and did
[myTestWindow setContentView:myView];
This one worked seamlessly. This makes me think my view is OK :-)
So, what else can I try to make the menu item display my own view?
Thanks!
It happened to be some weird side-effects of window-view autosizing setup in Interface Builder (let’s call them size-effects). In the Inspector you can setup how subviews get resized upon superview sizing. And so it was somehow broken in my case, such that when window gets small enough (menuitem-high), my elements just got drawn outside of the window’s frame.
I re-configured the sizing in IB, eliminating all the automatics I don’t need, and now it works perfectly: the view from IB gets displayed inside a menu item.
What is the height of the frame of the view? Maybe your view is taller than the menubar and you are drawing outside of it. The current menubar is 22 pixels, but you should ask the systemStatusBar for it's thickness, just in case it ever changes.
Try drawing a frame around your view to see if you are getting anything.
[[NSColor blueColor] set];
NSBezierPath *path = [NSBezierPath bezierPathWithRect:self.bounds];
[path setLineWidth:4.0f];
[path stroke];
If you get just an 'L' shape (the bottom left corner) of blue then the view is too large. If you get a rectangle but still no text then you may not be drawing the text inside the view, look at the coordinates you are drawing the text at (and review View Geometry). Putting the view in a window may have worked because it is larger.
For an example of using text in a status menu view take a look at Matt Gemmell's NSStatusItemTest project.
EDIT:
Sorry, somehow I missed where you said you created the view in IB. I did a quick test and I can see the white box you mentioned.
The docs for NSStatusItem's setView: states
The custom view is responsible for
drawing itself and providing its own
behaviors, such as processing mouse
clicks and sending action messages.
And status item views go into a special (apple private) window called NSStatusBarWindow that may have different internal behavior than normal windows and certainly seems to not support views from IB.
So yes, I think you need to create a custom NSView subclass and do your own drawing in drawrect:.

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