Sam's random musings

CoreGraphics Log Jam

CoreGraphics Log Jam:

It’s been a while since I’ve complained about Apple in the context of an actual bug report, so here is a little diversion back into “Apple Bug Friday” land.

[Snip]

Sure enough, a few levels into the API, I spot an examination of the input colorspace, and an objection to the fact that it was only 24-bits per pixel. Great, I thought. If the API knows exactly what’s wrong, why doesn’t it let us know somehow, at least through a logging message or something. Then I spotted a call to “CGPostError.” Well, that’s interesting. A well-defined error reporting mechanism? The results of which the developer never sees? I traced along a while until discovered myself in a logging function, the parameter to which was this choice bit of text:

CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component;
    24 bits/pixel; 3-component colorspace; kCGImageAlphaNone.

Well! It doesn’t exactly point to the right solution, but it would have been nice to know! Thanks for not sharing, CoreGraphics. Why the heck does it go to all this work and not print out the result? I decided to dig deeper.

[snip]

1. Should CoreGraphics limit its logging functionality based on assumptions about “/dev/tty”?
2. Should debugging in Xcode impact a target application’s ability to open “/dev/tty”?

These questions are posed in Radar #4538344- “CoreGraphics logging doesn’t appear withing Xcode”.

(Via Red Sweater Blog.)