UIView+Image.h

//
//  UIView+Image.h
//  ViewImage
//
//  Created by hechen on 15/4/8.
//  Copyright (c) 2015年 hechen. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIView(Image)

- (UIImage *)image;

@end

UIView+Image.m

//
//  UIView+Image.m
//  ViewImage
//
//  Created by hechen on 15/4/8.
//  Copyright (c) 2015年 hechen. All rights reserved.
//

#import "UIView+Image.h"

@implementation UIView(Image)

- (UIImage *)image{
    CGSize imageSize = [self bounds].size;
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    // Iterate over every window from back to front
    for (UIWindow *window in [[UIApplication sharedApplication] windows]){
        if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen]){
            // -renderInContext: renders in the coordinate space of the layer,
            // so we must first apply the layer's geometry to the graphics context
            CGContextSaveGState(context);
            // Center the context around the window's anchor point
            CGContextTranslateCTM(context, [window center].x, [window center].y);
            // Apply the window's transform about the anchor point
            CGContextConcatCTM(context, [window transform]);
            // Offset by the portion of the bounds left of and above the anchor point
            CGContextTranslateCTM(context, -[window bounds].size.width *[[window layer] anchorPoint].x, -[window bounds].size.height *[[window layer] anchorPoint].y);
            
            // Render the layer hierarchy to the current context
            [[window layer] renderInContext:context];
            
            // Restore the context
            CGContextRestoreGState(context);
        }
    }
    
    // Retrieve the screenshot image
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

@end