Mar 21, 2014
For my book I wanted to see if there is a way to see the performance impact of various settings. So I launched the Energy Diagnostics instrument for the first time. I was not able to conclusively demonstrate the impact of any capture setting, but I did see something odd. Even though my barcode scanner sample app does not have any need for audio data AV Foundation appears to insist on capturing and processing it.
As the energy diagnostics performance instrument indicates, this causes energy usage for “Audio Processing” even though for the purpose of scanning barcodes audio is not needed. In the least developers should be able to indicate to iOS that they have no use for audio processing so that the system can conserve this energy.
This bug report is filed as rdar://16389364 and on Open Radar.
Mar 18, 2014
There are 3 generators in Core Image for 2D barcodes, but only the one for creating QR codes is documented. So I filed a bug report suggesting that the documentation was “missing”. I also sent an email to the responsible Apple evangelist.
The response I got from Apple was that if something was not documented it is to be considered private. The bug report about adding the documentation for Aztec and PDF417 was closed.
Feb 05, 2014
While researching for my book “Barcodes and iOS” I was looking at the CoreImage generators for barcodes. iOS 7 supports generating QR, Aztec and PDF417 barcodes via CoreImage generators.
But for the latter two the documentation appears to be missing, making those – technically – private APIs. I believe this to be something that was simply overlooked, since those generators seem to work just fine.
Filed as rdar://15989297 and on Open Radar.
Update: An Apple evangelist responded to my inquiry and confirmed that those CI generators are indeed private API and should not be used.
Jan 16, 2014
While experimenting with PassKit I found some weird behavior which I believe might be a bug, or two.
Passes can have a date and locations where they are relevant. For event tickets – according to the documentation – the locations are optional. You expect to see passes to appear on the iOS lock screen from some time before the event until it starts.
Nov 15, 2013
This bug in iOS Simulator is interesting because it is the first bug we found where a crash in a simulated iOS app can be triggered by having a Mac app using Accessibility running outside of the simulator. I filed it and am reporting on this here because I’ve gotten this as issue on my project now two times.
Submitted as rdar://15478255 and to OpenRadar.
Oct 07, 2013
While working on unit tests for DTCoreText I stumbled upon an issue that has two aspects, one for how you set up unit tests and the other is a crash that is new as of Xcode 5.0.1.
Consider this simple unit test:
UIFont *font = [UIFont fontWithName:@"Helvetica"
STAssertNotNil(font, @"font should not be nil");
I consider it esoteric knowledge that you have to have a test host in place if you want to instantiate a UIFont inside a unit test. This is why I am filing it as a bug report, since it “might lead to developer confusion”.
In the least this should be documented somewhere. You will also find a description of a minimalistic workaround for both issues.
Oct 03, 2013
This bug has been causing me grief for the last month or so, as it was hard to pin down without a concrete use case that can reliably reproduce it. GitHub user brovador finally was able to narrow it down to be able to repro it every time.
There appears to be a bug in NSAttributedString that causes an EXC_BAD_ACCESS if you try to enumerate certain attributes over a longer range on two separate attributed strings from two background threads.
I filed it as rdar://15139980 and on Open Radar. The sample is the DTCoreTextExceptionExample on our Radar Samples GitHub repo.
Sep 26, 2013
The following issue is a head scratcher if you are trying to add unit tests to your project that both run on Mac and iOS. And if you like to use the new inline buttons for executing individual tests.
Filed as rdar://15085316 and Open Radar. The mentioned sample project is the UnitTestTest sample on our Radar Samples GitHub repo.
Sep 23, 2013
I’m seeing this issue on my main phone after having begun to use the iOS 7 GM on it.
Filed as rdar://15056186 and on Open Radar.