Magenta overlays are caused by subpixel misalignment, while yellow overlays are caused by stretching. Prior to iOS 4, Instruments used magenta for both.

I am a bit confused. There seem to be two different kind of Python packages, source distributions (setup.py sdist) and egg distributions (setup.py bdist_egg).

Both seem to be just archives with the same data, the python source files. One difference is that `pip`, the most recommended package manager, is not able to install eggs.

What is the difference between the two and what is &#39;the&#39; way to do distribute my packages?


(Note, I am not wanting to distribute my packages through PyPI, but I want to use a package manager that fetches my dependencies from PyPI)

What is the difference between an &#39;sdist&#39; .tar.gz distribution and an python egg?

I&#39;m trying to write some code that sets a property on a struct (important that it&#39;s a property on a struct) and it&#39;s failing:

    System.Drawing.Rectangle rectangle = new System.Drawing.Rectangle();
    PropertyInfo propertyInfo = typeof(System.Drawing.Rectangle).GetProperty(&quot;Height&quot;);
    propertyInfo.SetValue(rectangle, 5, null);

The Height value (as reported by the debugger) never gets set to anything - it stays at the default value of 0.

I have done plenty of reflection on classes before and this has worked fine.  Also, I know that when dealing with structs, you need to use FieldInfo.SetValueDirect if setting a field, but I don&#39;t know of an equivalent for PropertyInfo.

Is there a way to set properties on struct instances using reflection?

so--i switched on &quot;color misaligned images&quot; to improve drawing performance in our app. The documentation states: 

&gt; Puts a magenta overlay over images
&gt; whose source pixels aren&#39;t aligned to
&gt; destination pixels

I don&#39;t know what the yellow means however. (There is a &quot;Color Offscreen-Rendered&quot; option that uses yellow... does &quot;Color Misaligned Images&quot; also turn on this option?)

Anybody know?

TIA

What does yellow tinting represent when using &quot;color misaligned images&quot; on iPhone/iOS

so--i switched on "color misaligned images" to improve drawing performance in our app. The documentation states:
> Puts a magenta overlay over images
> whose source pixels aren't aligned to
> destination pixels
I don't know what the yellow means however. (There is a "Color Offscreen-Rendered" option that uses yellow... does "Color Misaligned Images" also turn on this option?)
Anybody know?
TIA

What is the maximum length of the alert text of an iOS push notification?

The [documentation][1] states that [the notification payload has to be under 256 bytes in total][2], but surely there must be a specific character limit for the alert text.

  [1]: https://developer.apple.com/go/?id=push-notifications
  [2]: https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/LegacyNotificationFormat.html#//apple_ref/doc/uid/TP40008194-CH14-SW1

What is the maximum length of a Push Notification alert text?

As a beginning iPhone programmer, what is the best practice for writing apps to be used either with iOS 5 or older versions? Specifically, should I continue using the release/retain of data, or should I ignore that? Does it matter?

iOS 5 Best Practice (Release/retain?)

I want to get the user name.  A simple text input dialog box.  Any simple way to do this?

What&#39;s a simple way to get a text input popup dialog box on an iPhone

I have a simple PHP webpage, and would like to return different content depending if it&#39;s accessed from an iPhone/iPad or from a web brower. How can I do that?

Check if PHP-page is accessed from an iOS device

This should be simple enough. 

I have an iPhone app with a TableView. How do I add the little classic arrow to the righthand side of each cell?

Adding the little arrow to the right side of a cell in an iPhone TableView Cell

I need to create a CGSize to compute text height of an arbitrary text with arbitrary length. UIKit has this nice method -sizeWithFont:constrainedToSize: and my text is only constrained in width, but not in height.

For this, I need to set the maximum possible CGFloat for the height.

Is there a constant like &quot;CGFloatMax&quot;?

Is there a constant for the maximum CGFloat value?

I&#39;m developing a web app that apparently is having problems in iOS devices. The problem is that I don&#39;t own an iOS device and I develop in Linux Ubuntu. I&#39;m looking for a way to emulate/simulate this OS in Linux (especially the browser), but haven&#39;t found anything.

So far, what I&#39;ve found is the iOS SDK&#39;s Simulator, but that is meant for the Mac. And also some emulator for Windows. Has anyone done this before?

Emulate/Simulate iOS in Linux

I just created a singleton method, and I would like to know what the function `@synchronized()` does, as I use it frequently, but do not know the meaning.

What does @synchronized() do as a singleton method in objective C?

I can add a border to a CALayer in this way:

	[webView.layer setBorderColor: [[UIColor colorWithRed:0.6 green:0.7 blue:0.2 alpha:1] CGColor]];
	[webView.layer setBorderWidth: 2.75];	

But is it possible to add a border only at one side? I only need a border at the bottom. Or can I reach this with other properties, e.g. frame, bounds, mask, ...?

![enter image description here][1]

Thanks for your help!

---------

@Control-V

			UIWebView *webView = [[UIWebView alloc] init];
			CALayer *webViewLayer = webView.layer;
			
			// now you can do a lot of stuff like borders:
			[webViewLayer setBorderColor: [[UIColor greenColor] CGColor]];
			[webViewLayer setBorderWidth: 2.75];  	

		
			
Have a look at the CALayer documentation:
https://developer.apple.com/documentation/quartzcore/calayer

And have a look here:
http://iosdevelopertips.com/cocoa/add-rounded-corners-and-border-to-uiwebview.html

  [1]: https://i.stack.imgur.com/zn3eu.jpg

CALayer: add a border only at one side

I have an endlessly looping `CABasicAnimation` of a repeating image tile in my view: 

    a = [CABasicAnimation animationWithKeyPath:@&quot;position&quot;];
    a.timingFunction = [CAMediaTimingFunction 
                          functionWithName:kCAMediaTimingFunctionLinear];
    a.fromValue = [NSValue valueWithCGPoint:CGPointMake(0, 0)];
    a.toValue = [NSValue valueWithCGPoint:CGPointMake(image.size.width, 0)];
    a.repeatCount = HUGE_VALF;
    a.duration = 15.0;
    [a retain];


I have tried to &quot;pause and resume&quot; the layer animation as described in [Technical Q&amp;A QA1673](http://developer.apple.com/library/ios/#qa/qa1673/_index.html). 

When the app enters background, the animation gets removed from the layer. 
To compensate I listen to `UIApplicationDidEnterBackgroundNotification` and call `stopAnimation` and in response to `UIApplicationWillEnterForegroundNotification` call `startAnimation`.

    - (void)startAnimation 
    {
        if ([[self.layer animationKeys] count] == 0)
            [self.layer addAnimation:a forKey:@&quot;position&quot;];
        
        CFTimeInterval pausedTime = [self.layer timeOffset];
        self.layer.speed = 1.0;
        self.layer.timeOffset = 0.0;
        self.layer.beginTime = 0.0;
        CFTimeInterval timeSincePause = 
          [self.layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
        self.layer.beginTime = timeSincePause;
    }
    
    - (void)stopAnimation 
    {
        CFTimeInterval pausedTime = 
          [self.layer convertTime:CACurrentMediaTime() fromLayer:nil];
        self.layer.speed = 0.0;
        self.layer.timeOffset = pausedTime;    
    }

The problem is that it starts again at the beginning and there is ugly jump from last position, as seen on app snapshot the system took when application did enter background, back to the start of the animation loop.

I can not figure out how to make it start at last position, when I re-add the animation. Frankly, I just don&#39;t understand how that code from QA1673 works: in `resumeLayer` it sets the layer.beginTime twice, which seems redundant. But when I&#39;ve removed the first set-to-zero, it did not resume the animation where it was paused. This was tested with simple tap gesture recognizer, that did toggle the animation - this is not strictly related to my issues with restoring from background.

What state should I remember before the animation gets removed and how do I restore the animation from that state, when I re-add it later?

Restoring animation where it left off when app resumes from background 

I&#39;m porting a block of code from an iOS4 project to iOS5 and I&#39;m having some troubles with ARC.  The code generates a PDF from a screen capture.

PDF Generation Code
&lt;pre&gt;&lt;code&gt;UIView *captureView;
...
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, captureView.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[captureView.layer renderInContext:pdfContext];
UIGraphicsEndPDFContext();&lt;/code&gt;&lt;/pre&gt;

The renderInContext line
&lt;pre&gt;&lt;code&gt;[captureView.layer renderInContext:pdfContext];&lt;/code&gt;&lt;/pre&gt;
generates the following error.
&lt;pre&gt;&lt;code&gt;Automatic Reference Counting issue
Receiver type &#39;CALayer&#39; for instance message is a forward declaration&lt;/code&gt;&lt;/pre&gt;

Any ideas what is going on here?

What does &quot;Receiver type &#39;CALayer&#39; for instance message is a forward declaration&quot; mean here?

I wish to create an animation. The best way I can explain this is if you can imagine drawing a circle. It starts at the top or 12 o clock and draws clockwise all the way around until it becomes a complete circle over the space of 10 or so seconds.

The closet I have come to this is to draw a point rotating around a center point using Core Animation (using the sample code [here][1]). But I am at a loss on how to draw the circle? Any suggestions are very welcome.

Many Thanks :)

  [1]: http://nachbaur.com/blog/core-animation-part-1

iPhone Core Animation - Drawing a Circle

I want to add a view under my tab bar analog in iOS and then show it with animation coming from behind it. But when I use my code, the view that must come from behind my tab bar  overlaps my tab bar for a while. 

![tab bar and a view that shows when tab bar button pressed][1]


  [1]: http://i.stack.imgur.com/72HWj.png

This is my code: 

    - (void)handlePressedButton {
    if (pressedButton.selected) {
        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:0.5];
        CGAffineTransform transform1 = CGAffineTransformMakeTranslation(-196.0, 0.0);
        CGAffineTransform transform2 = CGAffineTransformMakeTranslation(0.0, 0.0);
        [leftPanelView setTransform:transform1];
        [movedView setTransform:transform2];
        [UIView commitAnimations];
        pressedButton.selected = NO;
    }
    else {
        pressedButton.selected = YES;
        if (leftPanelView) {
            [leftPanelView removeFromSuperview];
            leftPanelView = nil;
        }
        CGRect viewFrame = CGRectMake(-196, 0, 236, 748);
        leftPanelView = [[UIView alloc] initWithFrame:viewFrame];
        leftPanelView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@&quot;left-nav-content.png&quot;]];
        
        // Code to populate leftPanelView according to what button is pressed.
        [self populateLeftPanelView];
        
        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:0.5];
        [self.view addSubview:leftPanelView];
        CGAffineTransform transform1 = CGAffineTransformMakeTranslation(236.0, 0.0);
        CGAffineTransform transform2 = CGAffineTransformMakeTranslation(112.0, 0.0);
        [leftPanelView setTransform:transform1];
        [movedView setTransform:transform2];
        [UIView commitAnimations];
    }
}

Here the leftPanelView is the view that must come under a tab bar. Moved view is another view, that is at the right of left panel (don&#39;t mind it)

How to add a view behind other view in iOS

in my iPad app, I&#39;d like to make a screenshot of a UIView taking a big part of the screen. Unfortunately, the subviews are pretty deeply nested, so it takes to long to make the screenshot and animate a page curling afterwards.

Is there a faster way than the &quot;usual&quot; one?

    UIGraphicsBeginImageContext(self.bounds.size);
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

If possible, I&#39;d like to avoid caching or restructuring my view.


iOS: what&#39;s the fastest, most performant way to make a screenshot programmatically?

I&#39;m trying to get `CIImage` from ImageView that display on the screen. 

    UIImage *image = myImageView.image;

convert image `UIImage` to `CIImage`.

    CIImage *cImage = [....];

How to do this? 

How to Convert UIImage to CIImage and vice versa

Hi i am searching a clean solution without overwriting `drawRect` or stuff like that to create a `UIView` with Rounded corners on the Top of the **View**. My main problem here is to create variable solution if the view is getting resized or something like that.
Is there a clean solution? **Apple** is this doing too on the first table item. it can&#39;t be so hard to do this.

Rounded Corners only on Top of a UIView

I was looking to be able to turn any UIColor into a gradient. The way I am intending to do this is by using Core Graphics to draw a gradient. What I am trying to do is to get a color, lets say:

    [UIColor colorWithRed:0.5 green:0.5 blue:0.5 alpha:1.0];
and get a UIColor which is a few shades darker and a few shades lighter. Does anyone know how to do this? Thank you.

Get Slightly Lighter and Darker Color from UIColor

We&#39;re making a user-space device driver for OS X that moves the cursor using Quartz Events, and we ran into a problem when games — especially ones that run in a windowed mode — can&#39;t properly capture the mouse pointer *(= contain/keep it within the boundaries of their windows)*. For example, it would go outside the game window and click on the desktop or nearby inactive applications.

We could fix this if only we could detect when an active application calls CGAssociateMouseAndMouseCursorPosition.

How would you do this? Any ideas are appreciated.

Detecting CGAssociateMouseAndMouseCursorPosition

Of all the Instruments Trace Templates, I love using:

* Zombies to detect where an object is getting over-released, great for debugging `EXEC_BAD_ACCESS` errors.
* Leaks to detect memory leaks.
* Core Animation w Color Blended Layers to detect frame rate &amp; translucent subviews, great for smoothing up `UITableView` scrolling.

I always hear people saying to profile my app&#39;s memory usage &amp; performance.

1. Why should I profile memory usage &amp; performance? My app runs fine.
2. How do I do it?

I&#39;ve used Allocations and see that my iPhone app starts at 1 MB total allocated memory and grows to 5 MB after normal usage. What is too high amount of memory usage on the iPhone? iPad? Mac?

How to profile memory usage &amp; performance with Instruments?

If I open Instruments and select a standard application (e.g. Mail or MS Word) it has no issue. 
If I am in Xcode and I go to **Product &gt; Profile** (or press &lt;kbd&gt;Cmd&lt;/kbd&gt; + &lt;kbd&gt;I&lt;/kbd&gt;), it launches Instruments, allows me to select a template, and loads the standard screen. Then the downward arrow starts tracing to the right as it should, and the iOS simulator launches the program. However, nothing is plotted in Instruments. It shows no changes to anything no matter what the app is doing. I can&#39;t click anything in Instruments: no menu&#39;s, can&#39;t stop recording, can&#39;t open tabs, etc. 

I randomly discovered that if I hit &lt;kbd&gt;Cmd&lt;/kbd&gt; + &lt;kbd&gt;Tab&lt;/kbd&gt;, Instruments will start behaving normally. This seems really strange to me. Either it&#39;s a bug or it&#39;s a hole in my knowledge about how to operate Instruments. 


Instruments 4.1 unresponsive to projects launched from Xcode 4.1 until pressing Cmd-Tab

I&#39;ve created a simple javascript for my `iOS` app that I&#39;d like to run simultaneously on multiple `iOSDevices` connected via USB to one host Mac machine. Launching instruments connected to an `iPhone` from the command line works fine but if I attempt to launch a second instruments connected to an `iPad`, the first instruments session hangs.  


----------


Upon terminating the first instruments session, I get one of more of the following lines printed:

&gt; Stopped: Script stopped due to device being disconnected

After extensive research on the subject, with no results on the phrase, I&#39;ve been trying to read into what is meant by Apple&#39;s Instruments Guide:

&gt; When you choose All Processes, Attach to Process, or Choose Target from the Target menu, Instruments sets the default target for all instruments to the program you choose. There are occasions, however, when you might want to set a different target for each instrument. You might want to sample two different programs at the same time, for example, using the Sampler instrument. If you have some instruments that are capable of tracing all processes, you might want them to do just that while single-process instruments sample just one process.

I&#39;m wondering if the `Automation.tracetemplate` is a single-process only instrument and that if another process is started with the same Automation trace then the first is usurped.

Any advice would be grateful as this is a major block for running our time intensive automation tests over multiple `iOSDevices`.


----------


**Update 27 Mar 2012**

The following is from an email received after submitting a bug to Apple on the matter (developer.apple.com/bugreporter):

&gt;I heard back from a UI Automation engineer. UI Automation is a single process Instrument. As such, you cannot use it simultaneously on multiple devices.


Instruments automation trace only allows one target connection?

Is it possible to track the allocation and deallocation of my Objective-C objects? For instance if I have a class Book, I want to track all the allocations and deallocations of the objects of Book type. I can track all the default SKD classes, such as UIViewController, UIWindow, UIView, NSDictionary and all that, but I want to track also the objects that are created from my defined classes.

Instruments Allocations track alloc and dealloc of objects of user defined classes

I have all my code signing entitlements set correctly. Running the app on my phone is fine, but launching it in instruments gives me an error message:

    Error Starting Recording
    At least one target failed to launch; aborting run

And then:

    Target failed to run. Permisson to debug [app name] was denied. The app must be signed with a development identity (i.e. iOS Developer)

Any ideas how I could stop this from happening? Doesn&#39;t happen on my iPad.

Content Type	Original Author	Original Content on Stackoverflow
Question	nielsbot	View Question on Stackoverflow
Solution 1 - Iphone	Wilbur Vandrsmith	View Answer on Stackoverflow

What does yellow tinting represent when using "color misaligned images" on iPhone/iOS

Iphone Problem Overview

Iphone Solutions

Solution 1 - Iphone

Is there a way to set properties on struct instances using reflection?

What is the difference between an 'sdist' .tar.gz distribution and an python egg?

Attributions