After I overlay an application over my previous application, I go back to previous application and encounter a few errors:
certain components have disappeared
only way to make the components visible is to resize the window
that seems to redraw the whole canvas.
Weird thing is that there are only a couple of components and drawn images that are missing
It doesn't always happen but only a couple of times
I haven't found a solid way to reproduce the problem.
Anybody have an Idea why this is happening?
I experienced exactly the same issue (view was updated correctly only after resizing), except that I've used OpenGL drawing in OSX game.
My problem was solved by adding this:
GLint vblSynch = 1;
[[self openGLContext] setValues:&vblSynch forParameter:NSOpenGLCPSwapInterval];
in my custom NSOpenGLView init method.
Then I've implemented:
- (void)drawRect:(NSRect)rect
{
[self destroyFramebuffer]; // glDeleteFramebuffers..
[self createFramebuffer]; // [super prepareOpenGl], glGenFrame(Render)Buffers, bind buffers, etc
[self drawView]; // [[self openGLContext] makeCurrentContext], make some drawing, [[self openGLContext] flushBuffer]..
}
like this.
After these changes, when window gets focus it redraws itself (without any resizing stuff :) ).
Hope this helps!
Related
Having tried many methods I still haven't found a good and full-proof way of preventing the usual "maps" from being shown behind custom map tiles that I am using. Ultimately I want my app to have a map page consisting only of a custom map.
I am really looking for a solution that is pure iOS and doesn't require any 3rd party software but it would appear difficult.
I have tried 3 methods already:
Number 1, hiding the background map via it's view:
NSArray *views = [[[self.mapView subviews] objectAtIndex:0] subviews];
[[views objectAtIndex:0] setHidden:YES];
this however doesn't work on a certain new operating system coming out very soon! The whole screen goes blank. The Apple Developer Forum hasn't provided a solution either
Number 2, Using another blank overlay (e.g. MKCircle) to cover the background map. This works however when scrolling or zooming out quickly, sometimes the overlay flickers off and you can briefly see the background map behind so not ideal.
Number 3, and this is what I have been working on for a few days now is to simply prevent the user from zooming out. Most documented methods tend to use regionDidChangeAnimated or regionWillChangeAnimated, however these do not seem to suddenly stop the map zooming out when pinching - they wait until the pinch movement has finished before taking effect so again it means the background map can be viewed briefly.
So now I am stumped, unless of course I have missed something with these other two methods.
So any help would be much appreciated!
Add this:
-(void)viewDidAppear:(BOOL)animated
{
MKTileOverlay *overlay = [[MKTileOverlay alloc] init];// initWithURLTemplate:tileTemplate];
overlay.canReplaceMapContent = YES;
[map addOverlay:overlay];
overlay = nil;
}
-(void)loadTileAtPath:(MKTileOverlayPath)path result:(void (^)(NSData *, NSError *))result
{
NSData *tile =nil;
}
-(MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay: (id<MKOverlay>)overlay
{
if ([overlay isKindOfClass:[MKTileOverlay class]])
{
MKTileOverlayRenderer *renderer = [[MKTileOverlayRenderer alloc] initWithOverlay:overlay];
[renderer setAlpha:0.5];
return renderer;
}
}
It will replace the map content from the background. It worked very well in my case where I am adding an overlay on the whole map and hiding the real map from the user.
You can't do this in current releases without a third-party library like MapBox. However, the future OS release that you speak of lets you do this.
I'm using the iCarousel library to show a coverflow-like UI. Animating the iCarousel subviews directly tends to blow up, so I create a wrapper for my animation and stick a subview inside of it which looks like the tapped cover. Then I hide the actual iCarousel view, and animate the fake cover on top of it.
I'm using UIView's transitionWithView:duration:options:animations:completion: method, but I'm running into some trouble. When animating another view onscreen for the first time, the view appears without any animation. When animating out, the view correctly flips and hides.
My view hierarchy is as follows:
main view, loaded from a nib
wrapper view
view to transition from
view to transition to
The view I'm transitioning to is a UINavigationController's view which contains a UITableViewController subclass. Instead of the initial animation, the UINavigationController appears and then the view grows upward a little, as if it's taking over the space otherwise occupied by a status bar.
Any idea why the table view might be animating like this? (I suspect containment APIs and/or wantsFullscreen, although I'm not explicitly using them. I simply install the views into the wrapper via addSubview:.)
Here's my "flip in" code, that animates every time but the first:
- (void) flipInWithCompletion:(MBTransitionCompletion)completion {
BOOL displayingPrimary = [self isDisplayingPrimaryView];
UIView *frontView = [self frontView];
UIView *backView = [self backView];
UIView *wrapperView = [self wrapperView];
[wrapperView addSubview:frontView];
[UIView transitionWithView:wrapperView
duration:0.8
options:UIViewAnimationOptionTransitionFlipFromRight
animations:^{
[wrapperView addSubview:backView];
[frontView removeFromSuperview];
}
completion:^(BOOL finished) {
[self setIsDisplayingPrimaryView:!displayingPrimary];
if (completion) {
completion();
}
}
];
}
What might cause the table view to grow instead of allowing the wrapper to flip?
Edit:
I've made a video demoing the exact problem.
Sounds like the view isn't properly loaded before it starts to animate in. I think I remember having a similar problem before. Try adding it to your view first, then remove it, and try to animate it into place to see if that fixes it.
That's not really a solution though, but it should give you a clue as to what might be wrong.
I'm experiencing a redraw problem on a CATiledLayer when the parent UIScrollView is zoomed in.
I'm rendering a PDF page in a CATiledLayer backed UIView. It has another UIImageView behind it, which contains a low-res image of the page that the CATiledLayer will draw. When I zoom in, it works as expected. The CATiledLayer will render a higher resolution image according to the zoom level.
The problem occurs after zooming. If I zoom in then just leave the iPad alone, the displayed image blurs then resharpens. It looks like the CATiledLayer is being removed, since I see the blurry low resolution image in the backing view, then the CATiledLayer gets redrawn, i.e. I see the tiling effect and the resharpening of the image. This happens if I just leave the app alone and wait about 30 to 40 seconds. I've only observed it on the iPad 3rd gen (New iPad, iPad3, whatever). I'm also testing on iPad2s and I have yet to encounter the issue.
Has anyone else encountered this problem? Any known cause and, possibly, solutions?
Edit:
My UIScrollViewDelegate methods are as follows:
// currentPage, previousPage, and nextPage are the pdf page views
// that are having the refresh problem
- (void)positionBufferedPages {
// performs math {code omitted}
// then sets the center of the views
[previousPage.view setCenter:...];
[nextPage.view setCenter:...];
}
- (void)hideBufferedPages {
if ([previousPage.view isDescendantOfView:scrollView]) {
[previousPage.view removeFromSuperview];
}
if ([nextPage.view isDescendantOfView:scrollView]) {
[nextPage.view removeFromSuperview];
}
}
- (void)showBufferedPages {
if (![previousPage.view isDescendantOfView:scrollView]) {
[scrollView addSubview:previousPage.view];
}
if (![nextPage.view isDescendantOfView:scrollView]) {
[scrollView addSubview:nextPage.view];
}
if (![currentPage.view isDescendantOfView:scrollView]) {
[scrollView addSubview:currentPage.view];
}
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return currentPage.view;
}
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view {
[self hideBufferedPages];
}
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollViewParam withView:(UIView *)view atScale:(float)scale {
[self positionBufferedPages];
[self showBufferedPages];
}
- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
// nothing relating to the pdf page view
// but does set the center of some other subviews on top of the pdf page views
}
Not sure how helpful this will be though, as the scrollview is not receiving input while the problem happens. As mentioned above, the pdf page is loaded to the CATiledLayer, then I leave the iPad alone (no input is received by the device), and the CATiledLayer will redraw by itself.
I've also tried catching calls to setNeedsDisplay, setNeedsDisplayInRect:, setNeedsLayout, and setNeedsDisplayOnBoundsChange: on both the view and the tiled layer, but the redraw happens without any of those functions getting called. drawLayer:inContext: gets called, of course, but the trace only shows some Quartz calls being started in a background thread (as expected, as tiled layers prepare the content in the background), so it is of no help either.
Thanks in advance!
How is your app's memory usage looking? CATiledLayer will discard its cache and redraw if a memory warning occurs. I've seen it do this even without memory warnings being sent to the app (just a higher than usual memory load). Use Instruments to see memory usage. You may need to use the OpenGL ES Driver instrument to see what's going on with graphics memory.
I spoke with an Apple engineer about this and the short answer is that iOS only has X amount of memory available for caching a CATiledLayer and on the Retina display of the iPad, there are just too many pixels to use more than one layer.
I had been using two CATileLayers to display a map view and a drawing view on top. I removed the second CATiledLayer and the problem went away.
I've had the exact same problem. In my case it was caused by using the UIGraphicsBeginImageContext() function; this function does not take scale into account, which gives problems on a retina display. The solution was to replace the call with UIGraphicsBeginImageContextWithOptions(), with the scale (=third) parameter set to 0.0.
If you based your code on the Zooming PDF Viewer sample code from Apple, like I did, chances are this will solve your problem too.
Longshot, any chance you are calling any methods on the views from the non-main thread? All sorts of unexpected funky stuff can happen if you do.
I am trying to add a UIButton to the view of a MPMoviePlayerController along with the standard controls. The button appears over the video and works as expected receiving touch events, but I would like to have it fade in and out with the standard controls in response to user touches.
I know I could accomplish this by rolling my own custom player controls, but it seems silly since I am just trying to add one button.
EDIT
If you recursively traverse the view hierarchy of the MPMoviePlayerController's view eventually you will come to a view class called MPInlineVideoOverlay. You can add any additional controls easily to this view to achieve the auto fade in/out behavior.
There are a few gotchas though, it can sometimes take awhile (up to a second in my experience) after you have created the MPMoviePlayerController and added it to a view before it has initialized fully and created it's MPInlineVideoOverlay layer. Because of this I had to create an instance variable called controlView in the code below because sometimes it doesn't exist when this code runs. This is why I have the last bit of code where the function calls itself again in 0.1 seconds if it isn't found. I couldn't notice any delay in the button appearing on my interface despite this delay.
-(void)setupAdditionalControls {
//Call after you have initialized your MPMoviePlayerController (probably viewDidLoad)
controlView = nil;
[self recursiveViewTraversal:movie.view counter:0];
//check to see if we found it, if we didn't we need to do it again in 0.1 seconds
if(controlView) {
UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
[controlView addSubview:backButton];
} else {
[self performSelector:#selector(setupAdditionalControls) withObject:nil afterDelay:0.1];
}
}
-(void)recursiveViewTraversal:(UIView*)view counter:(int)counter {
NSLog(#"Depth %d - %#", counter, view); //For debug
if([view isKindOfClass:NSClassFromString(#"MPInlineVideoOverlay")]) {
//Add any additional controls you want to have fade with the standard controls here
controlView = view;
} else {
for(UIView *child in [view subviews]) {
[self recursiveViewTraversal:child counter:counter+1];
}
}
}
It isn't the best solution, but I am posting it in case someone else is trying to do the same thing. If Apple was to change the view structure or class names internal to the control overlay it would break. I am also assuming you aren't playing the video full screen (although you can play it fullscreen with embeded controls). I also had to disable the fullscreen button using the technique described here because the MPInlineVideoOverlay view gets removed and released when it is pressed: iPad MPMoviePlayerController - Disable Fullscreen
Calling setupAdditionalControls when you receive the fullscreen notifications described above will re-add your additional controls to the UI.
Would love a more elegant solution if anyone can suggest something other than this hackery I have come up with.
My solution to the same problem was:
Add the button as a child of the MPMoviePlayerController's view;
fade the button in and out using animation of its alpha property, with the proper durations;
handle the player controller's touchesBegan, and use that to toggle the button's visibility (using its alpha);
use a timer to determine when to hide the button again.
By trial-and-error, I determined that the durations that matched the (current) iOS ones are:
fade in: 0.1s
fade out: 0.2s
duration on screen: 5.0s (extend that each time the view is touched)
Of course this is still fragile; if the built-in delays change, mine will look wrong, but the code will still run.
I have a CGContext, which I can turn into an NSGraphicsContext.
I have an NSWindow with a clipRect for the context.
I want to put a scrollview into the context and then some other view into the scrollview so I can put an image into it... However, I can't figure out how to attach the scrollview into the context.
Eventually the view will probably be coming from a nib, but I don't see how that would matter.
I've seen this thread, (http://lists.apple.com/archives/quartz-dev/2006/Nov/msg00010.html) But they seem to leave off the step of how to attach the view into the context, unless there's something obvious I'm missing.
EDIT:
The reason I'm in this situation is that I'm writing a Mozilla Plugin. The browser gives me a CGContext (Quartz) and a WindowRef (QuickDraw). I can turn the CGContext into an NSGraphicsContext, and I can turn the windowRef into an NSWindow. From another data structure I also have the clipping rectangle...
I'm trying to draw an image into that context, with scrollbars as needed, and buttons and other UI elements... so I need (want) an NSView...
You can't put a view into a graphics context. A view goes either into another view, or as the content view of a window.
You can draw a view into a context by setting that context as the current context and telling the view to draw. You might do this as a means of rendering the view to an image, but otherwise, I can't think of a reason to do it. (Edit: OK, being a Netscape plug-in is probably a good reason.)
Normally, a view gets its own graphics context in NSView's implementation of the lockFocus method, which is called for you by display, which is called for you by displayIfNeeded (only if the view needs display, obviously), which is called for you as part of the event loop.
You don't need to create a context for a view except in very rare circumstances, such as the export-to-an-image case I mentioned. Normally, you let the view take care of that itself.
A partial solution?
What I have done currently is create a nib with a button in an IKImageView inside an NSScrollView. I load this in my plugin.
Then, since I have the NSWindow, I can get the contentView of the window. Then, I add the scrollview as subview of contentView.
It appears, but there seems to be some coordinate confusion about where the origin is. (top vs bottom) and since I'm mucking with the contentview of the WHOLE WINDOW, I'm doing some stuff very globally that perhaps I should be doing more locally. Like, the view never disappears, even when you close the tab, or go to another tab. (it does close when you close the window of course)
So, does this sound like a reasonable way of doing this? it feels a bit ... kludgy...
For future generations (and me when I forget how I did this and Google leads me back to my own question) Here's how I'm doing this:
I have a NIB with all my views, I load this on start-up.
on SetWindow, I set the clip rect and actually do the attaching:
NP_CGContext* npContext = (NP_CGContext*) window->window;
NSWindow* browserWindow = [[[NSWindow alloc] initWithWindowRef:npContext->window] autorelease];
NSView* cView = [browserWindow contentView];
NSView* hitView = [cView hitTest:NSMakePoint(window->x + 1, clip.origin.y + 1)];
if (hitView == nil || ![[hitView className] isEqualToString:#"ChildView"])
{
return;
}
superView = [hitView retain];
[superView addSubview: topView];
[superView setNextResponder: topView];
[topView setNextResponder: nil];
[browserWindow makeFirstResponder: topView];
To make sure I only addSubView once, I have a flag...
And then in handleEvent, I actually draw, Because I'm using an IKImageView, I can use the undocumented method: [imageView setImage: image]; which takes an NSImage.
So far this seems to be working for me. Hopefully this helps someone else.