Model Widget Controller (MWC) aka: Apple "MVC" is not MVC

I probably should have taken more notice that time that after my question about why a specific piece of the UI code had been structured in a particular way, one of my colleagues at 6wunderkinder informed me that Model View Controller meant the View must not talk to the model, and instead the Controller is responsible for mediating all interaction between the View and the Model. It certainly didn't match the definition of MVC that I knew, so I checked the Wikipedia page on MVC just in case I had gone completely senile, but it checked out with that I remembered:

1. the controller updates the model,
2. the model notifies the view that it has changed, and finally
3. the view updates itself by talking to the model

(The labeling on the graphic on the Wikipedia is a bit misleading, as it suggests that the model updates the view, but the text is correct).

What I should have done, of course, is keep asking "Why?", but I didn't, my excuse being that we were under pressure to get the Wunderlist 3.0 release out the door. Anyway, I later followed up some of my confusion about both React.native and ReactiveCocoa (more on those in a later post) and found the following incorrect diagram in a Ray Wenderlich tutorial on ReactiveCocooa and MVVC.

Hmm...that's the same confusion that my colleague had. The plot thickens as I re-check Wikipedia just to be sure. Then I had a look at the original MVC papers by Trygve Reenskaug, and yes:

A view is a (visual) representation of its model. It would ordinarily highlight certain attributes of the model and suppress others. It is thus acting as a presentation filter. A view is attached to its model (or model part) and gets the data necessary for the presentation from the model by asking questions.

The 1988 JOOP article "MVC Cookbook" also confirms:

So where is this incorrect version of MVC coming from? It turns out, it's in the Apple documentation, in the overview section!

I have to admit that I hadn't looked at this at least in a while, maybe ever, so you can imagine my surprise and shock when I stumbled upon it. As far as I can tell, this architectural style comes from having self-contained widgets that encapsulate very small pieces of information such as simple strings, booleans or numbers. The MVC architecture was not intended for these kinds of small widgets:

MVC was conceived as a general solution to the problem of users controlling a large and complex data set.

If you look at the examples, the views are large both in size and in scope, and they talk to a complex model. With a widget, there is no complex model, not filtering being done by the view. The widget contains its own data, for example a string or a number. An advantage of widgets is that you can meaningfully assemble them in a tool like Interface Builder, with a more MVC-like large view, all you have in IB is a large blank space labeled 'Custom View'. On the other hand, I've had very good experiences with "real" (large view) MVC in creating high performance, highly responsive user interfaces.

Model Widget Controller (MWC) as I like to call it, is more tuned for forms and database programming, and has problems with more reactive scenarios. As Josh Abernathy wrote:

Right now we write UIs by poking at them, manually mutating their properties when something changes, adding and removing views, etc. This is fragile and error-prone. Some tools exist to lessen the pain, but they can only go so far. UIs are big, messy, mutable, stateful bags of sadness.

To me, this sadness is almost entirely a result of using MWC rather than MVC. In MVC, the "V" is essentially a function of the model, you don't push or poke at it, you just tell it "something changed" and it redraws itself.

And so the question looms: is react.native just a result of (Apple's) misunderstanding (of) MVC?

As always, your comments are welcome here or on HN.

Switching contact from SMS to iMessage

So my girlfriend finally got an iMessage capable phone, but Messages on my phone still insisted on sending SMSes. Even after starting to receive iMessages in the same conversation. Even after a message sent from the Messages app on OS X was duly noted as being an iMessage!

Various attempts to fix this state of affairs had no effect: changing the contact number to iPhone, deleting the conversation(s), twiddling with Messsages settings on both phones, including the "Send as SMS" preference.

What did work was performing a reset of the Network Settings.

Should you use CoreData?

The answer, of course, is "it depends".

Now that we have that out of the way, I want to have a look at Drew Crawford's You should use Core Data, which manages to come up with a less nuanced answer in its 2943 words. It's an older article (2012), but recently came to my attention via Drew McCormack (@drewmccormack): "Great post", he wrote, and after reading the article I not just disagreed, but found that Twitter wasn't really adequate for writing up all the things wrong with that article.

Where to start? Maybe at the beginning, right in the first paragraph the following is called out as a "myth":

Among them, Core Data is designed for something–not really sure what–but whatever it is, it’s a lot more complicated than what I need to do in my project.

First here is a categorical mistake, because unless Drew knows the exact requirements and engineering trade-offs in every iOS application, he can't know whether this is true or false, fact or myth.

The second mistake is that the basic statement "CoreData was designed for something else" is actually true. CoreData's design dates back to NeXT's Enterprise Object Framework or EOF for short, and EOF was designed as an ORM for talking to corporate relational database servers, with a variety of alternate back-ends for non-relational DBs (including the way cool 3270 adapter!).

Obviously the implementation is different and the design has diverged by now, but that is the basic design, and yes, that does do something that is more complicated than what some (many?) developers need.

Details.

Next sentence, next problem:

I just want to save some entities to disk.

I may well be reading too much into this, but using the word entities already bakes so many assumptions into the problem statement. When I actually do want to save entities, databases in general and CoreData in particular are somewhat higher on my list of technologies, but quite often I don't start with ERM, and therefore just have objects, XML or other data. While these could be ER-modeled with varying degrees of difficulty/success, they certainly don't have to be, and it's often not the best choice.

In the enterprise system described in REST: Advanced Research Topics and Practical Applications, we removed the database from the rewrite, because the variety of the data meant converting the DB into a key-value store one way or another, or having a schema that's about an A0 page in small print (a standards body had developed such a schema and I think we even got a poster). We instead ended up converging on an EventPoster architecture that kept the original XML feed files around and parsed them into objects as necessary. No ERM here.

The next couple of paragraphs go off on an ad-hominem straw man tangent making WAG assumptions about the provenance of iOS developers and more WAGs about why that (assumed) provenance causes said developers to have these misconceptions. Those "misconceptions" that actually turn out to be true. Although largely irrelevant, it does contain some actual misinformation. For example the fact that categories don't get linked with static libraries is not an LLMV bug, it's a consequence of the combined semantics of static libraries and Objective-C categories irrespective of compiler/linker versions.

Details.

Joel

Then there's another tangent to Joel Spolsky's article on Things You Should Never Do (the link in Drew's article is dead), such as rewriting legacy code from scratch, which Joel describes categorically as "single worst strategic mistake" that any software company can make. In the words of the great Hans Bethe: "Ach, that isn't in wrong!":

1. Just because Joel wrote something makes it right or applicable why?
2. While Joel makes some good points and is right to counter a tendency to not want to deal with existing code, his claim is most certainly wrong in its absoluteness, both empirically (the system referenced above was a rewrite with tremendous benefits, then there's OS X vs. trying to keep fixing Classic Mac OS indefinitely etc.) and logically: it only holds true if all your accumulated complexity is of the essential kind, and none if of the accidental kind. That idea seems ludicrous to me, virtually all software is rushed, has shifting requirements that are only understood after the fact, has historical limitations (such as having to run in 128KB of RAM on a 7MHz CPU with no MMU) etc.

   Sometimes a rewrite is warranted, though you should obviously be wary and not undertake such a project lightly.

3. Of course the biggest non-sequitur in the whole tangent is "How on earth does the problem of reading source code and rewriting legacy systems apply to this situation?". Apart from "not at all"? We don't have access to CoreData source code and there is no question about us rewriting it. Well, actually, I used to have such access, but even though my remit would have allowed some rewrites, I don't think I could have done a better job for the technology constraints chosen. The question is whether to use it or not, including whether the technology constraints are appropriate.
4. And no, not every persistence solution ends up as effectively a rewrite of CoreData.

Details

After that ill-conceived tangent, the article goes right back to the next unsubstantiated ad-hominem:

Here are some things you probably haven’t thought about when architecting your so-called data stack:

Apart from the attitude somewhat unbefitting to someone who gets so much wrong, well, Nein, but lets's look at some of these in detail:

• Handling future changes to the data schema: this just isn't hard if you're not using a relational database. In fact high variability of the schema was one of the reasons for ditching the DB in you know...
• Bi-directional synchronization with servers...hah hah...!
• Bi-directional synchronization with peers...see above
• Undo support: gosh, I wish there were some sort of facility that would manage undo support on my model objects, if I had my way, Apple would add this and call it NSUndoManager. Without such a useful class, I'll just have to do complicated things like renaming old versions of my data file or storing deltas.
• Multithreading. Really? Multithreading?? If you think CoreData makes multithreading easier rather than harder, I have both a nice bridge and some oceanfront property in Nevada to sell you.
• Device/time constraints: the performance ca(na)rd. CoreData is slow and memory intensive. It makes up for this by adding the ability and the requirement for the developer to continuously tune the working set, if that is an option. If continuously minimizing/tuning the working set is not an option (i.e. you have some large datasets), you're hosed.

Details

Magic

Then we're back to the familiar ad-hominems/straw-men and non-sequitur analogies for a couple of paragraphs, nothing to see there. The whole analogy to Cocoa is useless: yes, Cocoa is good. How does this make CoreData good (it may or may not be, there simply is no connection) or appropriate for my tasks? Also, Cocoa in particular and Apple code in general is not "magic". I've been there, I've seen it and I fixed some of it. A lot of it is good, some excellent, but some not so much (sleep(5) anyone?).

The section entitled But, there are times not to use CoreData, right? could have been the saving grace, but alas the author blows it again. Having a "mark all as read" option in a NewsReader application is a "strange" "corner case"? Right. Let me turn this section around: there is a very narrow range of application areas where CoreData is or might be appropriate. Mostly read-only data, highly regular (table-like) structure, no need for bulk operations ever, preferably no trees either and no binary data. Fairly loose performance requirements.

What Apple says

The section on "what Apple says" is also gold, though I have to give credit to the Apple doc writers for managing to strongly suggest things without actually explicitly claiming them, strongly enough to fool this particular writer:

Apple’s high-level APIs can be much faster than ‘optimized’ code at lower levels.

This is obviously true, but completely meaningless. My tricycle can be faster than a Ferrari, for example if the Ferrari is out of gas or has a flat tire, or just parked. When we actually measured the performance of applications adopting CoreData at Apple we invariably got a significant performance regression. Then a lot of effort would be expended by all the teams involved in order to fix the regression, optimization effort that hadn't been expended on the original application, usually making up some of the shortfall.

I find the code reduction claim also specious, at least when stated as an unquestionable fact like this. In my experience, code size was reduced when removing CoreData and its predecessor EOF. Had we had exactly the requirements that CoreData/EOF were designed for (talking to existing relational enterprise databases), the result would almost certainly been different, but those were not our requirements, and I doubt that most iOS apps have those requirements (and in fact, CoreData didn't even support taking to external SQL databases, at all, a puzzling development for all the EOF veterans).

For managing small amounts of data inside in iOS application, CoreData is almost always overkill, because it effectively simulates an entire client/server enterprise application stack within your phone or desktop. The performance and complexity costs to pay for that overkill are substantial.

So Should You Use Core Data?

As I wrote: it depends.

The article in question at least adds no useful information to answering that question, only inappropriate analogies, repeated claims without any supporting evidence and lots of ad-hominems that are probably meant to be witty. If you believe its last section, the only reason developers don't use CoreData is because they are naive, lazy or ignorant.

This is evidently not true and ignores even the most basic concepts that one would apply to answering the question, such as, say, fitness for purpose. CoreData may well be the best implementation of an in-process-ORM simulating a client-server enterprise app there is, and there is good evidence that this is in fact true (certainly the people on it are top notch and some of the code is amazing). However, all that doesn't help if that's not what you need.

Considering the gleefully paraded ignorance of not just alternatives but various other programming aspects, I'd take the unconditional advice this article gives with a pinch of salt. Mountain-sized pinch, that is.

Root View Controller and Autorotation

Must have the former or the latter won't work.

For some reason my Mussel Wind application was running fine without a root view controller, but with the annoying "Applications are expected to have a root view controller at the end of application launch" message. I vaguely remember autorotation being somewhat tricky, but in the end it was working and all was good.

Until I got the request to add zoom to the large version of the web cam view (you get it when you tap the image). Put in the scroll view, set it to zoomable, added the tap gesture recognizer. All good. Except nor more autorotation. Put in all the debugging messages for rotation masks, and shouldRotate etc. All called, but only on creation, not when the device is rotated. Nada.

On a whim, decided to fix the missing root view controller message by adding the view controller manually. First, no joy because UIKit was sending a "viewControllers" message that wasn't being handled. This despite the fact that my class is a straight UIViewController subclass and rootViewController is documented as taking just that. Oh well, just implement that as returning an empty NSArray and presto: autorotation!

More Objective-C Drawing Context Pleasantries

It's been a little over half a year since I first made my pleasant Objective-C drawing contextpublic, and I haven't been idle. In the process of retrofitting my own code to use MPWDrawingContext and adding more and more graphics (for example, I now do my icons in code), I've discovered a lot about making drawing with code a more pleasant experience.

Blocks

Blocks seem to be a really wonderful match for a graphics context, and most of the changes involve blocks in some way.

Bracketing operations such as gsave/grestore now have block versions, so the Objective-C block structure reflects the nesting:

    [context ingsave:^(Drawable c ){
        [c translate:@[ @130 ,@140]];
        [c setFont:[context fontWithName:@"ArialMT" size:345]];
        [c setTextPosition:NSMakePoint(0, 0)];
        [c show:@"\u2766"];
    }];

This is somewhat more compact than the plain code, which for correctness should also have a @try/@finally block wrapped around the basic drawing so exceptions don't mess up the graphics state stack.

    [context gsave];
    [context translate:@[ @130 ,@140]];
    [context setFont:[context fontWithName:@"ArialMT" size:345]];
    [context setTextPosition:NSMakePoint(0, 0)];
    [context show:@"\u2766"];
    [context grestore];

Similar for drawing shadows:

    [context withShadowOffset:NSMakeSize(0, -8 * scale) blur:12 * scale  color:[context  colorGray:0 alpha: 0.75] draw:^(Drawable c ){
        [[[c setFillColorGray:0.9 alpha:1.0] ellipseInRect:ellipseRect] fill];
    }];

Again, this seems a little clearer than having to explicitly set and unset, makes it harder to miss the end of the bracket when moving code around and remains exception-safe.

    [context sethadowOffset:NSMakeSize(0, -8 * scale) blur:12 * scale  color:[context  colorGray:0 alpha: 0.75]];
    [[[context setFillColorGray:0.9 alpha:1.0] ellipseInRect:ellipseRect] fill];
    [context clearShadow];

Stored, delayed and repeated drawing

You can create an object for later drawing by sending the -laterWithSize:(NSSize)size content:(DrawingBlock)commands message. For example, here is a simple diamond shape:

    NSSize diamondSize=NSMakeSize(16,16);
        id diamond = [context laterWithSize:diamondSize
                              content:^(id  context){
            id red = [context colorRed:1.0 green:0.0 blue:0.0 alpha:1.0];
            [context setFillColor:red];
            [[context moveto:diamondSize.width/2 :2] 
				lineto:diamondSize.width-2 :diamondSize.height/2];
            [[context lineto:diamondSize.width/2 :diamondSize.height-2]
				lineto:2 :diamondSize.height/2];
            [[context closepath] fill];
        }];

We can now draw this anywhere we want, and at any scale or orientation, using the -drawImage: message.

    [context drawImage:diamond];

You also have layerWitSize:content: and bitmapWithSize:content: messages if you want to specifically use CGLayer or CGImage instead, but using laterWithSize:content: preserves maximum quality, and it will automatically switch to a CGLayer when rendering to a PDF context in order to minimize PDF file size.

Patterns

I talked about patterns earlier. What I didn't mention then was that this is just the ability to use a stored set of drawing commands (see previous section) as a color:

    [context setColor:diamond];

I am not going to post the comparison to plain CG here, you can read it in the original Apple documentation.

I should note that this currently works for colored patterns, not for uncolored patterns, due to the fact that I haven't yet exposed color spaces. The basic process will be very similar.

Polymorphic object arguments

Path construction and graphics state messages with point arguments are now available in a version that takes a single object argument, in addition to the format with anonymous float arguments (moveto:(float)x :(float)y).

• moveto:
• lineto:
• translate:
• scale:

The single argument can be an Objective-C array:

    [context moveto:@[ @10, @20]];

Alternatively, any custom object that responds to count and either objectAtIndex:, (float)realAtIndex: or getReals:(float*)buffer length:(int)maxLen can be used. The scale: message can also take a single NSNumber and will treat that as uniform x and y scale.

Linecap parameters

Linecap parameters can now be set using distinct message:

• setlinecapRound
• setlinecapButt
• setlinecapSquare

Having multiple messages rather than a single message with a parameter probably seems odd, but it actually reduces the number of names involved, and these names are nicely scoped to this context. The constant strings or enums that are typically used have global scope and therefore tend to need ugly and hard-to-remember prefixes:

    [context setlinecapRound];

vs.

    [context setLinecap: kCGContextLinecapRound];

Future

Another reason to be as purely message-based as possible is that it makes bridging to other languages easier, for example for interactive drawing environments: Creating a badge (youtube).

I've also started experimenting with other outputs, for example creating a version of the same badge composed of CALayer objects using the same drawing commands. Other output should follow, for example web with SVG or HTML 5 Canvas or direct OpenGL textures.

I also want to finally add image processing operations both stand-alone and as chained drawing contexts, as well as getting more complex text layout options in there.

p.s.: now on hacker news

CGLayer performance and quality

The CoreGraphics CGLayer object seems to keep causing confusion. I hope I can clear that up a bit.

The intent of CGLayer was to have some sort of object for optimized repeated drawing, similar to how you would call a drawing procedure multiple times, have multiple instances of a view or simply draw the same PDF or bitmap image multiple times. The difference was supposed to be that the drawing layer could do secret magic "stuff" to optimize the repeated instance drawings. Not giving away the specific representation or optimizations performed means that whatever is done can be adapted both to different contexts and with changing technology.

Currently, that primarily means a texture stored on the graphics card, and that is and was one of the possible optimizations. However, the reasoning for such an opaque optimized object goes back further, at least to NeXTStep/Rhapsody: DisplayPostscript was implemented as a server process, and despite Mach's fast memory-remapping messages, shipping images back and forth between the client and server was not an optimization, and so you couldn't use (client side) bitmaps for optimized drawing. Well you could, but it wouldn't be optimized.

With Quartz becoming a client-side drawing library in Mac OS X, some of the reasons for these distinctions disappeared, but the distinctions (such as NSBitmapImageRep vs. NSCachedImageRep) remained. I think there were plans for CGLayer to become a kind of NSCachedImageRep on steroids, for example maintaining OpenGL display lists, but as far as I could tell, those plans never really panned out: in my tests drawing a CGLayer always looked the same as drawing a cached bitmap, and also performed similarly.

In 10.5, most of the accumulated cruft was cleaned up, NSBitmapImageRep for examples is now only a fairly thin wrapper around its underlying CGImage, and NSCachedImageRep was deprecated completely in 10.6, as it no longer has any advantages. With these changes, drawing a CGImage or a NSBitmapImageRep became as fast as possible, with CGImages stored on the graphics card. At this point CGLayer was essentially abandoned, and for drawing to the screen, you can just as easily use a NSBitmapImageRep, CGImage, UIImage etc.

So is CGLayer now completely useless? Not quite! It turns out that when drawing to a PDF context, CGLayer will generate a PDF Form object, which stores the original drawing commands (vectors, text, images). This is obviously much better than drawing a bitmap, both in terms of quality and in terms of file size and performance.

So if your plans include printing or generating a PDF, then I would recommend taking a look at CGLayer for repeated drawing of (vector) content.

CoreGraphics, patterns and resolution independence (not just) for retina displays

In a recent post with followup, Mark Granoff demonstrates how to intelligently deal with the need for higher resolution backgrounds by using CoreGraphics pattern images, particularly using the [UIColor colorWithPatternImage:] method. However, he does wonder why he still has to deal with retina resolution issues at some points in the code, when "…the docs say that CoreGraphics handles scaling issues automatically."

That's a good question, and the answer lies in the fact that the example uses pattern images and mask images, rather than CoreGraphics patterns and geometric primitives. Once you explicitly ask for bitmap representations, you will be dealing with pixels and different resolution. The clue is to avoid going to pixels as much and as long as possible. The doughnut shape, for example, can easily be achieved using basic geometry and a little knowledge of the Postscript/PDF fill rules.

Using the standard "nonzero-winding-number" rule, a doughnut effect can be achieved by having the two arcs that are nested inside each other drawn in opposite directions. That's one of the reasons the extra "clockwise" parameter exists.

---

  NSPoint centerPoint = NSMakePoint([view frame].size.width/2, 150);
  [context arcWithCenter:centerPoint
           radius:50 
           startDegrees:0
           endDegrees:360  
           clockwise:YES];
  [context arcWithCenter:centerPoint
           radius:100
           startDegrees:0
           endDegrees:360  
           clockwise:NO];
  [context fill];

---

(The code examples here use MPWDrawingContext for convenience, pure CoreGraphics code tends to be two to three times more verbose). The second way to achieve the doughnut would be to just use the even/odd fill rule, in which case the direction doesn't matter. matter.

Patterns can also be specified geometrically, or rather with callbacks to draw the pattern shape. Objective-C Blocks are really a perfect fit for specifying these sorts of callbacks, but were only introduced much later than the CoreGraphics pattern callback API. The following code shows how to specify the diamond pattern via an Objective-C block, courtesy of some glue API provided by MPWDrawingContext.

---

        NSSize patternSize=NSMakeSize(16,16);
        id diamond = [context laterWithSize:patternSize
                              content:^(id  context){
            id red = [context colorRed:1.0 green:0.0 blue:0.0 alpha:1.0];
            [context setFillColor:red];
            [[context moveto:patternSize.width/2 :2] 
				lineto:patternSize.width-2 :patternSize.height/2];
            [[context lineto:patternSize.width/2 :patternSize.height-2]
				lineto:2 :patternSize.height/2];
            [[context closepath] fill];
        }];
        [context setFillColor:diamond];
        [[context nsrect:[[self view] frame]] fill];

---

The "laterWithSize:content:" message creates a callback object that not only encapsulates the block, but also implements a -CGColor method so the callback can be used directly as a color in -setFillColor:.

With all the graphics specified using pure geometry, CoreGraphics can now do its thing and automatically handle varying device resolutions, wether it's a retina display or a zoomable interface or even print, all without ever having to deal with the different resolutions in code. Although I haven't tested it, the code should also use less memory, because it doesn't create potentially large temporary bitmaps, and for the cherry on top it's also a fraction of the code. CoreGraphics rules!

Forked project on github.

Found another reason for code signing to fail

I usually only build in Release mode, even when developing, both because of potential differences between release and debug modes and because of difficulties with dependencies in Xcode. I was always a little worried that this would bite me, especially with iOS, because here Release means building for distribution, right?

Surprisingly, it never did, until I installed an Xcode upgrade just now. Suddenly, my in-development iPad app stopped building for my attached device (development mode). The error was

"warning: Application failed codesign verification. The signature was invalid, contains disallowed entitlements, or it was not signed with an iPhone Distribution Certificate. (-19011)"

After doing all the usual certificate song-and-dance routines, I finally figured out that a flag was (now?) set in the build settings: "Validate Build Product", which was set to "Yes" for "Release" and "No" for "Debug".

Never having seen it before, I can't say wether the setting itself had changed or something in the environment, but setting it to "No" for "Release" as well fixed the problem.

radr:10876615 Allow signed binaries on iOS

Summary: OS X 10.8 Mountain Lion has a setting to allow binaries to be installed that are signed by registered developers. Please add this feature to iOS.

Filed as 10876615

PhoneGeometry.h

One things that's been tripping me up a bit when writing code that's supposed to be portable between iOS and Cocoa is the removal of NSPoint, NSSize, NSRect and their associated functions from Foundation in iOS. This is a real shame, because otherwise the Foundations are highly compatible.

One way to rectify this situation would be to start using CG* structs and functions on the desktop as well. However, this introduces a dependency on CoreGraphics that shouldn't be there for Foundation-based code.

My alternative is to standardize on NSPoint and friends, and map those to their CG alternatives on iOS. That way, I have minimized my dependencies, with only a small header file to pay for it: PhoneGeomtry.h

This is now part of MPWFoundation (on github).

---

//
//  PhoneGeometry.h
//  MPWFoundation
//
//  Created by Marcel Weiher on 11/11/10.
//  Copyright 2010-2011 Marcel Weiher. All rights reserved.
//


#if TARGET_OS_IPHONE
#ifndef PHONE_GEOMETRY
#define PHONE_GEOMETRY
#import <CoreGraphics/CoreGraphics.h>
typedef CGRect NSRect;
typedef CGPoint NSPoint;
typedef CGSize NSSize;
#define NSMakeRect  CGRectMake
#define NSMakePoint CGPointMake
#define NSMakeSize  CGSizeMake
#define NSEqualPoints  CGPointEqualToPoint
#define NSEqualRects   CGRectEqualToRect
#define NSIntersectsRect  CGRectIntersectsRect
static inline NSString *NSStringFromRect( CGRect r ) { return [NSString stringWithFormat:@"(%g,%g - %g,%g)",r.origin.x,r.origin.y,r.size.width,r.size.height]; }
static inline NSString *NSStringFromPoint( CGPoint p ) { return [NSString stringWithFormat:@"(%g,%g)",p.x,p.y]; }
static inline NSString *NSStringFromSize( CGSize s ) { return [NSString stringWithFormat:@"(%g,%g)",s.width,s.height]; }



#endif
#endif