IOS Custom Swipe back gesture

/**

Just change to the following code in your custom navigation controller, and the custom gesture returns

*/

#define Key_window [[UIApplication sharedapplication] Keywindow]

#define KSCREENW KEY_WINDOW.bounds.size.width

#define Kanimateduration 0.3

#define KDEFAULTALAPA 0.5

#define Kdefaultscale 0.95

#define IOS7 ([Uidevice currentdevice].systemversion.floatvalue >= 7.0)

#import "CXNavigationController.h"

#import <QuartzCore/QuartzCore.h>

@interface Cxnavigationcontroller ()

{

Nsmutablearray *_images; // Image Array

UIView *_bgview; // Background Map

UIView *_blankmask; // Masks

Uiimageview *_imageview; // Image

cgpoint _startpoint; // start point of contact

}

@end

@implementation Cxnavigationcontroller

-(void) viewdidload{

[Superviewdidload];

_images = [nsmutablearrayarray];

if (! iOS7) {

uipangesturerecognizer *pan = [[uipangesturerecognizeralloc] initwithtarge T:selfAction:@selector(panmove:)];

[self. ViewAddgesturerecognizer:p an];

}

}

-(void) Panmove: ( Uipangesturerecognizer *) pan{

if (self.) viewcontrollers. Count <= 1) {

return;

}

cgrect Selff = self. View. frame;

cgpoint location = [Pan locationinview:Key_window];

if (pan. State == Uigesturerecognizerstatebegan) { // start dragging

_startpoint = location;

_imageview. Image = [_imageslastobject];

[key_windowinsertsubview:_bgviewbelowsubview:Self c13>. Tabbarcontroller . View ];

_imageview. Transform = Cgaffinetransformmakescale(kdefaultscale, kdefaultscale);

}Elseif(pan. State == Uigesturerecognizerstatechanged) { // drag in

cgfloat Marginx = location. x - _startpoint. x;

Marginx = marginx > kscreenw ? kscreenw : Marginx;

Marginx = Marginx < 0 ? 0 : Marginx;

Selff. Origin. x = Marginx;

Self. View. frame = Selff;

cgfloat scale = Kdefaultscale + marginx * 1.0 / 6400;

Scale = Marginx = = kscreenw ? 0.5 : scale;

Scale = Marginx = = 0 ? 0 : scale;

_imageview. Transform = Cgaffinetransformmakescale(scale, scale);

cgfloat alpha = Kdefaultalapa -(1 - kdefaultalapa) * Marginx * 1.0 / kscreenw;

Alpha = Marginx = = kscreenw ? Kdefaultalapa : Alpha;

Alpha = Marginx = = 0 ? 0 : Alpha;

_blankmask. Alpha = Alpha;

}Elseif(pan. State == uigesturerecognizerstateended) { // End

cgfloat Marginx = location. x - _startpoint. x;

if (Marginx > ) {

Marginx = marginx > kscreenw ? kscreenw : Marginx;

cgfloat dur = kanimateduration -Marginx * 1.0 / ;

[UIViewanimatewithduration:d ur animations: ^{

cgrect Selff = self. View. frame;

Selff. Origin. x = Key_window. bounds. size. width;

Self. View. frame = Selff;

_blankmask. Alpha = 0;

_imageview. Transform = Cgaffinetransformmakescale(1, 1);

} Completion: ^ (BOOL finished) {

[_images removelastobject];

[_bgview removefromsuperview];

cgrect rect = self. View. frame;

Rect.Origin. x = 0;

Self. View. frame = rect;

[Superpopviewcontrolleranimated:NO];

}];

}Else{

cgfloat Marginx = location. x - _startpoint. x;

Marginx = marginx > ? : Marginx;

Marginx = Marginx < 0 ? 0 : Marginx;

cgfloat dur = Marginx * 1.0 / ;

[UIViewanimatewithduration:0.1 + dur animations: ^ {

cgrect Selff = self. View. frame;

Selff. Origin. x = 0;

Self. View. frame = Selff;

}];

}

}

}

-(void) Pushviewcontroller: (uiviewcontroller *) Viewcontroller animated: (BOOL) animated{

if (self. Viewcontrollers. Count > 0 ) {

if (! iOS7) {

[ self createbg];

}

}

[Super pushviewcontroller: Viewcontroller animated: animated];

}

#pragma mark Create a background

-(void) createbg{

[_imagesaddobject: [self currentscreenimage]];

if (! _bgview) {

_bgview = [[UIView alloc] initwithframe:key_window. Bounds];

_bgview. BackgroundColor = [uicolorblackcolor];

_imageview = [[uiimageview alloc] initwithframe:key_window. Bounds];

_imageview. BackgroundColor = [uicolorclearcolor];

[_bgviewaddsubview:_imageview];

_blankmask = [[UIView alloc] initwithframe:key_window. Bounds];

_blankmask. BackgroundColor = [uicolorblackcolor];

_blankmask. Alpha = Kdefaultalapa;

[_bgviewaddsubview:_blankmask];

}

}

#pragma mark Gets the current screen

-(UIImage *) currentscreenimage{

uigraphicsbeginimagecontextwithoptions(key_window. bounds . size , Self . View . Opaque , 0.0 );

if (self. Topviewcontroller. Tabbarcontroller) {

[self. Topviewcontroller. Tabbarcontroller. View. Layerrenderincontext:uigraphicsgetcurrentcontext()];

}Else{

[self. View . layerrenderincontext:uigraphicsgetcurrentcontext()];

}

UIImage * img = uigraphicsgetimagefromcurrentimagecontext();

uigraphicsendimagecontext();

return img;

}