Conflict with GPUImage library

[k06a]

I have crash while animation if simultaneously use GPUImage for another image filtering...
Details in this issue: BradLarson/GPUImage#761
What is my problem?

[Ciechan]

Could you provide a pet project showing the issue, or at least provide a list of steps to recreate it?

[k06a]

I've just started animation and starting to filter an image => app fails. Only animation works perfect. Only image filtering works perfect. But both them not works...

[k06a]

I found a problem... This is how animation invokes GPUImage filtering.
Why animation makes relayout?

* thread #1: tid = 0x1c03, 0x000767fd Pictography`-[GPUImagePicture initWithCGImage:smoothlyScaleOutput:] + 173 at GPUImagePicture.m:39, stop reason = breakpoint 4.1
    frame #0: 0x000767fd Pictography`-[GPUImagePicture initWithCGImage:smoothlyScaleOutput:] + 173 at GPUImagePicture.m:39
    frame #1: 0x0007662a Pictography`-[GPUImagePicture initWithCGImage:] + 90 at GPUImagePicture.m:20
    frame #2: 0x000637ad Pictography`-[GPUImageFilter newCGImageByFilteringCGImage:orientation:] + 93 at GPUImageFilter.m:235
    frame #3: 0x000639a7 Pictography`-[GPUImageFilter imageByFilteringImage:] + 135 at GPUImageFilter.m:255
    frame #4: 0x00018097 Pictography`-[HNPSepiaImageFilter processImage:] + 103 at HNPSepiaImageFilter.m:25
    frame #5: 0x00011cf4 Pictography`-[HNPEditorViewController tableView:cellForRowAtIndexPath:] + 6132 at HNPEditorViewController.m:370
    frame #6: 0x007bcf4b UIKit`-[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] + 412
    frame #7: 0x007bd01f UIKit`-[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] + 69
    frame #8: 0x007a580b UIKit`-[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] + 1863
    frame #9: 0x007b619b UIKit`-[UITableView layoutSubviews] + 241
    frame #10: 0x0075292d UIKit`-[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 279
    frame #11: 0x017ce6b0 libobjc.A.dylib`-[NSObject performSelector:withObject:] + 70
    frame #12: 0x00351fc0 QuartzCore`-[CALayer layoutSublayers] + 240
    frame #13: 0x0034633c QuartzCore`CA::Layer::layout_if_needed(CA::Transaction*) + 468
    frame #14: 0x00351eaf QuartzCore`-[CALayer layoutIfNeeded] + 166
    frame #15: 0x0034effe QuartzCore`-[CALayer renderInContext:] + 153
    frame #16: 0x00035b84 Pictography`-[UIView(Genie) renderSnapshotWithMarginForAxis:] + 420 at UIView+Genie.m:293
    frame #17: 0x0003312d Pictography`-[UIView(Genie) genieTransitionWithDuration:edge:destinationRect:reverse:completion:] + 413 at UIView+Genie.m:151
    frame #18: 0x00032f71 Pictography`-[UIView(Genie) genieOutTransitionWithDuration:startRect:startEdge:completion:] + 161 at UIView+Genie.m:128
    frame #19: 0x0001a932 Pictography`-[HNPHomeEditorSegue beginHomePushAnimation] + 2226 at HNPHomeEditorSegue.m:90
    frame #20: 0x0001ed42 Pictography`-[HNPHomeEditorSegue pushSegue] + 994 at HNPHomeEditorSegue.m:216
    frame #21: 0x0000a090 Pictography`-[HNPHomeViewController tableView:didSelectRowAtIndexPath:] + 2240 at HNPHomeViewController.m:435
    frame #22: 0x007b18d5 UIKit`-[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1194
    frame #23: 0x007b1b3d UIKit`-[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 201
    frame #24: 0x011b8e83 Foundation`__NSFireDelayedPerform + 380
    frame #25: 0x0233b376 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
    frame #26: 0x0233ae06 CoreFoundation`__CFRunLoopDoTimer + 534
    frame #27: 0x02322a82 CoreFoundation`__CFRunLoopRun + 1810
    frame #28: 0x02321f44 CoreFoundation`CFRunLoopRunSpecific + 276
    frame #29: 0x02321e1b CoreFoundation`CFRunLoopRunInMode + 123
    frame #30: 0x0270f7e3 GraphicsServices`GSEventRunModal + 88
    frame #31: 0x0270f668 GraphicsServices`GSEventRun + 104
    frame #32: 0x0070265c UIKit`UIApplicationMain + 1211
    frame #33: 0x00002de5 Pictography`main + 181 at main.m:16
    frame #34: 0x00002ce5 Pictography`start + 53

[Ciechan]

As you can see in the call stack it's not me who is calling [CALayer layoutIfNeeded], it's the Apple's implementation of [CALayer renderInContext:]. Unfortunately I can't do anything about this, this is just how CoreAnimation works.

One solution I can think of is to temporarily disable call to [HNPSepiaImageFilter processImage:] inside [HNPEditorViewController tableView:cellForRowAtIndexPath:] when you know you're just about to animate using genie effect.

[k06a]

@Ciechan, thank you! I've solved problem - my table delegate was unready to cell creation while this update...

[Ciechan]

I'm glad it works!