How is the red rectangle drawn? I don't have any great insight right now other than the fact that the change you are talking about happens at a specific place. When the top aligns with the red rectangle. You might consider color space or something like that. Maybe (and I am most certainly guessing right now. pure conjecture) the problem has to do with mixing with the grey?
On Thu, Mar 22, 2012 at 6:59 AM, Markus Spoettl <ms_li...@shiftoption.com>wrote: > Hello all, > > I have a super-strange issue that I have debugged for hours without any > progress. I'm at a complete loss to explain what is going on and would > appreciate ideas on getting to the bottom of this. > > I have a custom layer-hosting view with a delegate-drawn hierarchy, there > are no filters involved. The hierarchy is like this: > > rootLayer > |-- moveableLayer > |-- stationaryLayer > > I can click-drag "movableLayer" around using the mouse. moveableLayer's > opacity is 0.5, stationaryLayer's is 1.0. > > My problem is that stationaryLayer is composited differently, sometimes > opaque, sometimes semi-transparent and I cannot explain why. It's > completely reproducible and happens 100% of the time, even after rebooting. > > During the mouse-drag, I'm only changing moveableLayer's position > property, wrapped in a CATransaction with +setDisableActions:YES). The > opacity properties of neither layer are changed after creating them. > > To make sure no code accidentally changes opacity, I've added an observer > to the opacity property of all layers involved, so I'm sure. I've also > checked the observation works. > > Here's a short video that illustrates the issue: > > http://www.shiftoption.com/**temp/magic-layer-transparency.**mov<http://www.shiftoption.com/temp/magic-layer-transparency.mov> > > rootLayer drawn gray with a red rectangle in the middle, moveableLayer > consists of the transparent white rectangle and a green-to-blue gradient. > stationaryLayer is drawn with a yellow-to-red gradient. As you can see, at > a certain point during the drag stationary switches from being composited > transparently to completely opaque (relative to moveableLayer). > > All colors used have an alpha of 1.0. Also, the layers are never re-drawn > during the drag, so it's not a painting issue. > > The problem goes away when setting moveableLayer's opacity to 1.0. Then > stationaryLayer is composited the same, independent of moveableLayer's > position. > > I'm on Lion 10.7.3 using the 10.7 SDK with Xcode 4.3.1. > > Any ideas greatly appreciated! > > Thanks > Markus > -- > ______________________________**____________ > Markus Spoettl > ______________________________**_________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at > cocoa-dev-admins(at)lists.**apple.com<http://lists.apple.com> > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/**mailman/options/cocoa-dev/** > griotspeak%40gmail.com<https://lists.apple.com/mailman/options/cocoa-dev/griotspeak%40gmail.com> > > This email sent to griotsp...@gmail.com > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
