====== SHPinchEvent ======
---- dataentry extension ----
type            : extension
author_mail     : shilo86@gmail.com Shilo White
description     : A simple pinch event.
lastupdate_dt   : 2011-06-04
compatible      : v1.X
depends         : 
tags            : pinch, event, pinchevent
homepage_url    : https://gist.github.com/1346529
download_url    : https://gist.github.com/gists/1346529/download
min iOS version : 3.2
----

===== Description =====
SHPinchEvent class will allow you to easily listen to pinch events inside Sparrow. The event will hold the local touch location, scale, velocity, and number of touches. It also contains a method to get the location based on spaces that inherit SPDisplayObject. Note: SHPinchEvent will only bubble to display objects with bounds containing the touch location.

===== Sample =====
(Coming later)

===== Example =====
<code objc>
@implementation Game
- (id)initWithWidth:(float)width height:(float)height {
        if (self = [super initWithWidth:width height:height]) {
		//start pinch recognizer
		[self.stage startPinchRecognizer];
		
    		SPQuad *quad = [SPQuad quadWithWidth:50 height:50];

		//add a swipe event listener
		[quad addEventListener:@selector(onPinch:) atObject:self forType:SH_EVENT_TYPE_PINCH];

    		[self.stage addChild:quad];
        }
        return self;
}

- (void)onPinch:(SHPinchEvent *)event {
    	SPPoint *localLocation = event.location;
    	SPPoint *globalLocation = [event locationInSpace:self.stage];
    	float scale = event.scale;
    	float velocity = event.velocity;
   	uint numberOfTouches = event.numberOfTouches;
}

- (void)dealloc {
	//stop and remove pinch recognizer
	[self.stage stopPinchRecognizer];
	
	[self removeChild:mContainer];
	[super dealloc];
}
@end
</code>

===== Instructions =====
==== To add into your Sparrow project ====
  - Download the source files here: [[https://gist.github.com/gists/1346529/download]]
  - Open your desired Sparrow project
  - Drag and drop the files into the "Groups & Files" pane
  - Open "Game.h"
  - Include the extension: <code objc>#include "SHPinchEvent.h"</code>
  - Save "Game.h"
==== To add directly into Sparrow source ====
  - Download the source files here: [[https://gist.github.com/gists/1346529/download]]
  - Save the files into Sparrow's "/Classes/" directory
    * Example: "/sparrow/src/Classes/"
  - Navigate back one directory and open "Sparrow.xcodeproj"
    * Example: "/sparrow/src/Sparrow.xcodeproj"
  - Inside the "Groups & Files" pane, locate the "Events" group folder
    * Example: "Sparrow -> Classes -> Events"
  - Right click the "Display" group folder and click "Add -> Existing Files.."
  - Navigate into the "/Classes/" directory and select "SHPinchEvent.h" and "SHPinchEvent.m", then click "add"
  - On the next window, leave all options as default and click "add"
  - In the "Groups & Files" pane, Open "Sparrow.h"
    * Example "Sparrow -> Classes -> Sparrow.h"
  - At the bottom of the file, add: <code objc>#import "SHPinchEvent.h"</code>
  - Save "Sparrow.h"
  - Close "Sparrow.xcodeproj"
===== Troubleshooting =====
==== Why is it not recognizing Pinches? ====
Make sure you add this line before listening for a SHPinchEvent:
<code objc>[self.stage startPinchRecognizer];</code>

==== Why am I getting a runtime error/crash? ====
If you are encountering this runtime error:
<code objc>*** Terminating app due to uncaught exception 'NativeViewDoesNotExist', reason: 'nativeView not linked to stage yet.'</code>

Inside your ApplicationDelegate, I suggest you link your Game class to sparrowView (SPView) BEFORE initializing your Game class, like so:
<code objc>
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    SP_CREATE_POOL(pool);
 
    [SPStage setSupportHighResolutions:YES];
    [SPAudioEngine start];
 
    Game *game = [Game alloc];
    sparrowView.stage = game;
    game = [game init];
    [game release];
 
    [window makeKeyAndVisible];
    [sparrowView start];
 
    SP_RELEASE_POOL(pool);
 
    return YES;
}
</code>

//Warning: Although this method works fine in this situation, it might not be safe to get an instance of other Apple/Sparrow classes before initialization. The class might release and initialize a new instance of itself in the "init" method, which would make the old instance invalid.//

You could also call "startPinchRecognizer:" method after SPStage is linked to SPView.

===== Source Code =====
%gist(d22c35483be9d7a2b734)%

===== Changelog =====
  * //2011-06-04:// First version

===== Todo =====
  * (Empty)