NSWindow redraws issues / flickers on resize
I recently noticed that some controls (NSTableView and NSOutlineView) in my application flicker when the application window is resized.
I can't figure out why this is happening. I have scaled down my application to the bare minimum: one document window controller with a window containing a schematic view and a button. No background processing, no loading document data, etc.
Here is a screenshot showing the UI snippets when the window is resized:
Notice the fragment of the diagram from above, on a white background and the shadow of the offset window.
There is also a baseline graph warning in the console (see below). Not sure if this is related to the problem.
The app runs on Mac OS X 10.10.1, the deployment target and base SDK are set to 10.9.
Console output (not crash):
<Warning>: void CGSUpdateManager::log() const: conn 0x22833 token 0x10dfffffffff3823
<Warning>: Backtrace (at 4250.73):
<Warning>: void CGSUpdateManager::log() const: 0 CoreGraphics 0x00007fff986f5215 CGSBacktraceCreate + 59
<Warning>: void CGSUpdateManager::log() const: 1 CoreGraphics 0x00007fff98714688 _ZN16CGSUpdateManager14disable_updateEv + 84
<Warning>: void CGSUpdateManager::log() const: 2 AppKit 0x00007fff8e4e2de5 -[NSWindow disableScreenUpdatesUntilFlush] + 127
<Warning>: void CGSUpdateManager::log() const: 3 AppKit 0x00007fff8e4a2250 -[NSView _gainedLayerTreeHostAncestor] + 385
<Warning>: void CGSUpdateManager::log() const: 4 AppKit 0x00007fff8e4a20ae -[NSView _recursiveGainedLayerTreeHostAncestor] + 27
<Warning>: void CGSUpdateManager::log() const: 5 AppKit 0x00007fff8e4a667a -[NSScroller _recursiveGainedLayerTreeHostAncestor] + 103
<Warning>: void CGSUpdateManager::log() const: 6 AppKit 0x00007fff8e70da56 -[NSScroller _setSurfaceBacked:] + 213
<Warning>: void CGSUpdateManager::log() const: 7 AppKit 0x00007fff8e67324f -[NSScrollView setScrollerStyle:] + 304
<Warning>: void CGSUpdateManager::log() const: 8 AppKit 0x00007fff8ed0af27 +[NSScrollerImpPair _updateAllScrollerImpPairsForNewRecommendedScrollerStyle:] + 426
<Warning>: void CGSUpdateManager::log() const: 9 CoreFoundation 0x00007fff8b36fcbc __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
<Warning>: void CGSUpdateManager::log() const: 10 CoreFoundation 0x00007fff8b2611b4 _CFXNotificationPost + 3140
<Warning>: void CGSUpdateManager::log() const: 11 Foundation 0x00007fff8b5f8ea1 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
<Warning>: void CGSUpdateManager::log() const: 12 CoreFoundation 0x00007fff8b2d154c __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
<Warning>: void CGSUpdateManager::log() const: 13 CoreFoundation 0x00007fff8b2c3655 __CFRunLoopDoBlocks + 341
<Warning>: void CGSUpdateManager::log() const: 14 CoreFoundation 0x00007fff8b2c2e0e __CFRunLoopRun + 910
<Warning>: void CGSUpdateManager::log() const: 15 CoreFoundation 0x00007fff8b2c2838 CFRunLoopRunSpecific + 296
<Warning>: void CGSUpdateManager::log() const: 16 HIToolbox 0x00007fff9980043f RunCurrentEventLoopInMode + 235
<Warning>: void CGSUpdateManager::log() const: 17 HIToolbox 0x00007fff998000be ReceiveNextEventCommon + 179
<Warning>: void CGSUpdateManager::log() const: 18 HIToolbox 0x00007fff997ffffb _BlockUntilNextEventMatchingListInModeWithFilter + 71
<Warning>: void CGSUpdateManager::log() const: 19 AppKit 0x00007fff8e4266d1 _DPSNextEvent + 964
<Warning>: void CGSUpdateManager::log() const: 20 AppKit 0x00007fff8e425e80 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 194
<Warning>: void CGSUpdateManager::log() const: 21 AppKit 0x00007fff8e419e23 -[NSApplication run] + 594
<Warning>: void CGSUpdateManager::log() const: 22 AppKit 0x00007fff8e4052d4 NSApplicationMain + 1832
<Warning>: void CGSUpdateManager::log() const: 23 MyApp 0x00000001000022eb main + 75
<Warning>: void CGSUpdateManager::log() const: 24 libdyld.dylib 0x00007fff97a025c9 start + 1
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For reference, I have found the root cause, although I cannot explain it.
In applicationDidFinishLaunching:
I initialized a generic window controller instance and showed its window by calling showWindow:nil
. This window contained NSTableView
. This kind of table caused flickering in another outline view (in an unlinked window).
Why? I honestly have no idea. I removed all controls from the window and added an empty table view directly from the Interface Builder palette -> a problem occurs. After deleting the table view, the problem went away.
The solution was to not immediately open the window in applicationDidFinishLaunching:
. Instead, I added a menu to open it later (it was the debug info window).
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My solution was to bring this window front after very little delay, i.e .:
- (void)awakeFromNib {
if (WSPreferences.currentApplication.showActivityWindow) {
// http://stackoverflow.com/questions/27794135/nswindow-redraw-issues-flickers-when-resized
//
[self performSelector:@selector(makeKeyAndOrderFront:) withObject:self afterDelay:0.1];
}
}
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