> In the meantime however, I found one (surprising) cause of the performance
> issue. After making the versions *more* equivalent the issue become
> apparent. I restructured the second version (using the C++ iterators) and
> will discuss this in more detail. The culprit is in the consumer part
... and more importantly I do not believe your code makes correct use of
dispatch_group_async. Your first call adds a producer block to the global
concurrent queue, which may start executing immediately. At some time soon
afterwards you add a consumer block to the global concurrent queue, which
Hi Andreas,
If I understand your post correctly, you are saying that you see a performance
drop of 3x when using an iterator in your inner loop as opposed to using
hand-written C code to do the iterating. Unfortunately you say you haven't
actually posted the code relating to the iterator... but
This is probably a very basic conceptual question but one I haven't been able
to find a clear answer to. It concerns the "retain" qualifier on a class
property. I can declare for example:
@property (nonatomic, readwrite, retain) id latestFrame
The objects are retained and released correctly if I
Thanks again for your replies. I tried your various suggestions and they did
not directly solve the problem, but trying them out gave me a lot more clues to
help understand what was going wrong. It was in fact your mention of
setNeedsDisplay that prompted me to look at the actual low-priority dr
Thanks very much for your reply Ken, very helpful indeed.
>> The problem can be summarised as: in spite of having a backlog of
>> notifications building up on the main thread, NSPostWhenIdle-qualified
>> notifications do seem to be making it through. This is causing me problems
>> because this
Hi folks,
This is inevitably a bit of a vague question, but I am hoping somebody may have
some words of wisdom to offer nonetheless. The problem can be summarised as: in
spite of having a backlog of notifications building up on the main thread,
NSPostWhenIdle-qualified notifications do seem to
Hi WT,
>> If I understand you correctly, what you're saying about your variable
>> "__block SomeObjType foo" is not true. Regardless of the __block qualifier,
>> foo is effectively a stack-based variable, so two simultaneously-executing
>> threads have their own independent instance of that var
I am afraid I am not completely sure what you mean by your first problem, but
hopefully my answer to your second one sidesteps your concern there. In answer
to your second (once I had parsed out the two different uses of the word
"block" in what you said!)...
> The second problem is that the pa
On 14 Apr 2011, at 13:45, Mike Abdullah wrote:
>
> Bindings will not do this for you. Instead, hook your controller up to the
> text field's action, which will be sent every time the user hits return.
Thanks very much, that's working nicely. Requires a few more outlets etc to be
set up, but I g
I haven't managed to work out how to get the behaviour I want from my
interface, and I'm hoping somebody can help me out. It may be that I am
misusing my interface elements, but any suggestions would be welcome.
What I believe I want is for the appropriate setXXX method to be called when I
pres
OK, after much wailing and gnashing of teeth I have worked out my mistake.
Where I wrote the following:
> NSImage *frameImage = [[NSImage alloc]
> initWithContentsOfFile:NSStringForFrameNumber(i)];
>
> // Temp code to debug serious memory leak
> NSAutoreleasePool * pool = [[NSA
I am battling a leak in my code and can't work out what I am doing wrong. I
have a loop which accesses the raw bitmap data from a series of TIFF files I
load from disk. My calls to [bitmapRep bitmapData] seem to (understandably)
allocate memory, but I cannot work out how to allow that memory to
On 7 Mar 2011, at 13:45, Graham Cox wrote:
>> I have another UI type question where I am not sure how best to achieve what
>> I want. I have a (non-modal) window in which the user interacts with
>> external peripherals. Under certain circumstances (such as the peripheral
>> not being turned on)
Hi all,
I have another UI type question where I am not sure how best to achieve what I
want. I have a (non-modal) window in which the user interacts with external
peripherals. Under certain circumstances (such as the peripheral not being
turned on) it is not possible to send commands to the dev
>> Question 2 - the method you have described seems to be very much tied to a
>> single NSObjectController for the entire window, and indeed IB just seems to
>> offer the option to bind to "Object Controller", without specifying "which
>> one". In that case, is there any way of achieving neat gr
> Question 2 - the method you have described seems to be very much tied to a
> single NSObjectController for the entire window, and indeed IB just seems to
> offer the option to bind to "Object Controller", without specifying "which
> one". In that case, is there any way of achieving neat group-
Thanks again for your help, and thanks in particular for your follow-up email,
which was a great help in working out the bindings (it was indeed the first
time I'd done anything like that!). I have a couple of follow-up questions if
you don't mind.
Question 1 - you state "Nothing in any of this
On 4 Mar 2011, at 19:09, Quincey Morris wrote:
> On Mar 4, 2011, at 03:40, Jonathan Taylor wrote:
>
>> I have a window with a large number of editable text fields, and a big "Go"
>> button. The text fields are bound to values in my class. At the moment if
>&
I have a window with a large number of editable text fields, and a big "Go"
button. The text fields are bound to values in my class. At the moment if there
is an edit of one of the values in progress and then I press "Go" then the
"old" value for that field is the one in my class variable that i
f fields, you could avoid creating outlets for all of them
> by using distinct tags to find and operate on them.
>
> You won't need a custom button to accomplish this behavior (though you may
> have another reason for subclassing it).
>
> wp
>
> Sent from my iPad
Is there an easy way of determining where the user has clicked in an image
displayed in an NSImageView? This strikes me as a reasonable thing to want to
do, but I can't work out how.
When I get the mouseDown event in my NSImageView subclass, I can call:
thisMousePoint = [self convertPoin
It seems that InterfaceBuilder won't let me wire up my custom control to send
an action to itself. This suggests to me that I am going the wrong way about
what I am trying to do, or missing something really obvious. Can anybody advise?
My window has a number of text fields. One represents the cu
On 21 Feb 2011, at 23:49, Ken Thomases wrote:
> What makes you think the data copy is "extra"?
>
> If you read that AppKit release note, you'll see that NSImage may not be
> decoding the file contents right off the bat. For example, it mentions that
> "[i]f you initialize a NSImage from a JPEG
> I too have ran into this issue recently, with an old project that is
> half-resurrected.
>
> Performance was good in 10.5, but now horrible in 10.6. I'm not sure
> what to do instead.
>
> The CIImage docs say "Core Image images are immutable", and indeed I
> don't see any method like bitmapDat
On 21 Feb 2011, at 21:29, Quincey Morris wrote:
> On Feb 21, 2011, at 13:19, Jonny Taylor wrote:
>
>> So do I understand it correctly that there is no way at all of peeking (read
>> only) at the pixels of a NSBitmapImageRep without triggering a copy? That's
>> a bit of a shame if so - guess I'll
I am looking at the performance of my code, and have found that rather a lot of
time is spent in [NSBitmapImageRep getBitmapDataPlanes]. This is rather
disappointing because I had assumed this was a 'trivial' way of getting a
pointer to the actual data store itself in the case of raster data.
I
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